text:
User:Eml4500.f08.Lulz.Layton.Eric/Hw1

=Homework 1= University of Florida

Department of Mechanical and Aerospace Engineering

Fall 2008

EML4500: Finite Element Analysis and Design

Team Name: Lulz

Group Members:
 * Aaron Fisher
 * Eric Layton (Group Coordinator)
 * Sam Miorelli
 * Ben Mitchell
 * John Saxon
 * Andrew Strack

Submitted: Friday, September 12, 2008

Part 1: Accessing MATLAB
The first step is to open MATLAB by selecting the MATLAB icon. This is done by installing MATLAB on the local drive.

Part 2: Entering matrices
MATLAB works with rectangular matrices. Matrices can be entered into MATLAB using several different methods. Below is one method in which a matrix can be entered:

>> A = [1 2 3; 4 5 6; 7 8 9]

A =

1    2     3     4     5     6     7     8     9

Below is another method in which a matrix can be entered:

>> A = [1 2 3 4 5 6       7 8 9]

A =

1    2     3     4     5     6     7     8     9

The elements of a matrix can be separated by a comma or a space. When entering a number in exponential format spaces should be avoided (e.g. 2.34e-9). Complex numbers can also be entered into MATLAB. Blank spaces should also be avoided when entering complex numbers, and either i or j can be entered as the imaginary number.

When entering large matrices, it is often easier to enter these numbers in a text editing program. Several built-in functions exist in MATLAB such as rand(n) which allows the user to create an n x n matrix with randomly generated entries that distributed between 0 and 1. Individual entries can be referenced with parentheses. Using an example A(2,3) means the entry in the second row, third column of matrix A. Another example would be x(3), which denotes the third coordinate of vector x.

Part 3: Matrix operations, array operations
MATLAB is capable of addition, subtraction, multiplication, powers, conjugate transposes, left division, and right division. These operations apply to scalars as well. An error message will occur if the sizes of the matrices do not match up. Division is a special case. When matrix A is an invertible square matrix and b is a compatible column, resp. row, vector, then the following is true:

x = A\b is the solution of A * x = b and x = b/A is the solution of x * A = b

Array operations are also relevant in MATLAB. Matrix operations, which include *, ^, \, and /, are made to operate by inserting a period directly afterwards. For example,

>> [1,2,3,4].* [1,2,3,4]

ans =

1    4     9    16

>> [1,2,3,4].^2

ans =

1    4     9    16

Part 4: Statements, expressions, variables; saving a session
MATLAB uses statements as you type since it is an expression language. This is in the form:

variable = expression, or just expression

Expressions are made of operators, functions, and variable names. Several statements can be placed on the command line if it is separated by commas or semicolons. Commands, functions, and variables are case sensitive. For example, solveUT is not the same as solveut. The command who or whos lists all the variables that are currently being used in the workspace. The command variablename can be issued to clear a variable from the workspace.

There is a permanent variable called eps (epsilon) that give a unit roundoff in MATLAB which is equal to about 10^-16 on most machines. A infinite loop can be stopped by CTRL-C on a laptop or CTRL-BREAK on a PC. When logging out or exiting MATLAB all variables are considered lost. A non-human-readable file can be created to save all variables written in the command window called matlab.mat. When restarting MATLAB, all variables saved before will automatically be loaded.

Part 5: Matrix building functions
There are many matrix building functions in MATLAB. These include eye, zeros, ones, diag, triu, tril, rand, hilb, magic, toeplitz.

Zeros(m,n) produces an m-by-n matrix of zeros and zeros(n) produces an n-by-n matrix.

>> zeros(5,4)

ans =

0    0     0     0     0     0     0     0     0     0     0     0     0     0     0     0     0     0     0     0

>> zeros(3)

ans =

0    0     0     0     0     0     0     0     0

Another example is if A is a matrix, then zeros(size(A)) will produce a matrix of zeros having the same size as A.

>> A = [1 2 3; 4 5 6; 7 8 9]

A =

1    2     3     4     5     6     7     8     9

>> zeros(size(A))

ans =

0    0     0     0     0     0     0     0     0

When x is a vector, the function diag(x) is a diagonal matrix with x down the diagonal of the matrix. When A is a square matrix, then the function diag(A) is vector that has A down the diagonal.

>> A = [ 1 2; 3 4]

A =

1    2     3     4

>> diag(diag(A))

ans =

1    0     0     4

In MATLAB, matrices can also be built from blocks. If A is a 3-by-3 matrix, then

B = [A, zeros(3,2); zeros(2,3), eye(2)]

should build a 5-by-5 matrix.

>> A = [1 2 3; 4 5 6; 7 8 9]

A =

1    2     3     4     5     6     7     8     9

>> B = [A, zeros(3,2); zeros(2,3), eye(2)]

B =

1    2     3     0     0     4     5     6     0     0     7     8     9     0     0     0     0     0     1     0     0     0     0     0     1

Part 6: For, while, if - and relations
MATLAB handles most common computer code concepts like any other modern computer programming language. This includes for and while loops, if statements, and relational conditions.

For
for loops can be used very effectively in MATLAB to create matrices.

Ex 1: If you wanted to create a series of vectors where each value in the vector is the square of the index value of the position of the value in the vector, you could use this for loop:  EDU>> x = []; for i = 1:3, x=[x,i^2], end x =

1 x =

1    4 x =

1    4     9 The expression x = []; i = 3:-1:1, x=[x,i^2], end will give the same thing, except in reverse.

Ex 2: for loops can also be used to produce the Hilbert matrix. (Coding note, the semicolon prevents an intermediate printing which would be undesirable and the final H tells MATLAB to print the resulting H matrix.)  for i = 1:3 for j = 1:3 H(i,j) = 1/(i+j-1); end end H H =

1.0000   0.5000    0.3333    0.5000    0.3333    0.2500    0.3333    0.2500    0.2000

While
A while loop executes some command repeatedly so long as the condition it checks remains true.

Ex: MATLAB can calculate for a given number a, the smallest value n such that 2^n is less than or equal to a:  n = 0; a = 12; while 2^n  if n<0 parity = 0; elseif rem(n,2) == 0 parity = 2; else parity = 1; end

Relations
MATLAB uses the following relational operators in its programming language: < less than > greater than <= less than or equal to >= greater than or equal to == equal ~= not equal & and ~ not
 * or

Part 7: Scalar functions
MATLAB functions that are designed to operate on scalars can also be applied to matrixes, they will simply do so element-wise on the matrix elements. These are some common MATLAB functions that work in such a manner: sin, cos, tan, asin, acos, atan, ex, log, rem, abs, sqrt, sign, round, floor, ceil

Part 8: Vector functions
MATLAB functions that are designed to operate on vectors can also be applied to M x N matrixes (M >= 2), they will simply do so column-by-column which will produce a row vector containing the results of their operation in each column. To get these functions to operate on a row-by-row basis, use the transpose of the matrix. Common MATLAB functions that work like this are: max, min, sort, sum, prod, median, mean, std, any, all

These functions can also be nested within each other. Ex: to get the maximum single value in matrix A, use max(max(A)).

Part 9: Matrix functions
MATLAB has many matrix functions automatically built in for ease of use. These dramatically simplify programming and creating useful results from the software. These are the most useful of the functions: eig - Eigenvalues and Eigenvectors chol - Cholesky factorization svd - single value decomposition inv - inverse lu - LU factorization qr - QR factorization hess - Hessenberg form schur - Schur decomposition rref - reduced row echelon form expm - matrix exponential sqrtm - matrix square root poly - characteristic polynomial det - determinant size - size norm - 1-norm, 2-norm, F-norm, infinity-norm cond - condition number in the 2-norm rank - rank

As in other MATLAB functions, these can be used several ways. Ex: y = eig(A) and simply inputting eig(A) produce the same results. The output can also go to another matrix, [U,D] = eig(A) will produce a matrix with columns as the eigenvalues of A and a diagonal matrix D with the eigenvalues on the diagonals. This all may seem elementary, the point is that if there is a desired form of an output in MATLAB for a function, it is likely possible given the proper syntax.

Part 10: Command line editing and recall
The command line in MATLAB can be edited like most other text editors (usin up and down arrows, home and end keys, etc.). Full details of how the command line can be edited will be printed from the help cedit command.

Previous commands can be accessed using the up and down arrows on the command line. This is frequently more efficient than producing a full M-file for small problems. Commands may also be placed sequentially on the same command line using semi-colons to separate the commands.

Part 11: Submatrices and colon notation
This section of the primer discusses more advanced matrix manipulation techniques.

 >> 0.2:0.2:1.2
 * The first example shows the use of non-integral increments and boundaries in matrix declaration:

ans =

0.2000   0.4000    0.6000    0.8000    1.0000    1.2000 >> 5:-1:1

ans =

5    4     3     2     1  >> x = [0.0:0.1:2.0]';
 * The next example employs a table of  values to demonstrate matrix generation from a set of vectors:

>> y = sin(x);

>> [x y]

ans =

0        0

0.1000   0.0998

0.2000   0.1987

0.3000   0.2955

0.4000   0.3894

0.5000   0.4794

0.6000   0.5646

0.7000   0.6442

0.8000   0.7174

0.9000   0.7833

1.0000   0.8415

1.1000   0.8912

1.2000   0.9320

1.3000   0.9636

1.4000   0.9854

1.5000   0.9975

1.6000   0.9996

1.7000   0.9917

1.8000   0.9738

1.9000   0.9463

2.0000   0.9093  >> A = rand(5)
 * The following set of examples display the various uses of the colon operator in MATLAB:

A =

0.8147   0.0975    0.1576    0.1419    0.6557

0.9058   0.2785    0.9706    0.4218    0.0357

0.1270   0.5469    0.9572    0.9157    0.8491

0.9134   0.9575    0.4854    0.7922    0.9340

0.6324   0.9649    0.8003    0.9595    0.6787

>> B = rand(5)

B =

0.7577   0.7060    0.8235    0.4387    0.4898

0.7431   0.0318    0.6948    0.3816    0.4456

0.3922   0.2769    0.3171    0.7655    0.6463

0.6555   0.0462    0.9502    0.7952    0.7094

0.1712   0.0971    0.0344    0.1869    0.7547 >> A(1:4,3)

ans =

0.1576

0.9706

0.9572

0.4854 >> A(:,3)

ans =

0.1576

0.9706

0.9572

0.4854

0.8003 >> A(1:4,:)

ans =

0.8147   0.0975    0.1576    0.1419    0.6557

0.9058   0.2785    0.9706    0.4218    0.0357

0.1270   0.5469    0.9572    0.9157    0.8491

0.9134   0.9575    0.4854    0.7922    0.9340 >> A(:,[2 4])

ans =

0.0975   0.1419

0.2785   0.4218

0.5469   0.9157

0.9575   0.7922

0.9649   0.9595 >> A(:,[2 4 5]) = B(:,1:3)

A =

0.8147   0.7577    0.1576    0.7060    0.8235

0.9058   0.7431    0.9706    0.0318    0.6948

0.1270   0.3922    0.9572    0.2769    0.3171

0.9134   0.6555    0.4854    0.0462    0.9502

0.6324   0.1712    0.8003    0.0971    0.0344 >> A(:,[2,4]) = A(:,[2,4])*[1 2;3 4]

A =

0.8147   0.5232    0.1576    0.7626    0.6557

0.9058   1.5438    0.9706    2.2440    0.0357

0.1270   3.2941    0.9572    4.7567    0.8491

0.9134   3.3341    0.4854    5.0838    0.9340

0.6324   3.8434    0.8003    5.7677    0.6787  >> x = A(:,1)
 * The final set of examples for this section explores reordering of vectors using both colon notation and the  and   commands.

x =

0.8147

0.9058

0.1270

0.9134

0.6324 >> x = x(5:-1:1)

x =

0.6324

0.9134

0.1270

0.9058

0.8147 >> y = fliplr(x)

y =

0.6324

0.9134

0.1270

0.9058

0.8147 > y = flipud(x')

y =

0.6324   0.9134    0.1270    0.9058    0.8147

Part 12: M-files: script files, function files
This section of the primer discusses MATLAB's M-file system for executing command sequences. MATLAB handles two types of M-files: scripts and functions.

Script files
 First, the MATLAB code saved as : A = [
 * The first example shows the use of a simple script for creating a matrix:

1234

5678

];

And then the execution of the script to create the matrix:

>> data

>> A

A =

1234

5678

Function files
 First, the MATLAB code saved as the function : function a = randint(m,n,a,b)
 * The next example employs a function to generate a n-by-m matrix of random numbers from 0 to 9:

%RANDINT Randomly generated integral matrix.

%   randint(m,n) returns and m-by-n such matrix with entries

%   between 0 and 9.

%   rand(m,n,a,b) return entries between integers a and b.

if nargin < 3, a = 0; b = 9; end

a = floor((b-a+1)*rand(m,n)) + a;

And the calling of the function to generate a 4-by-5 matrix: >> z = randint(4,5)

z =

2    1     5     5     5

6    4     2     6     1

6    9     7     8     1

1    3     2     9     2

 First, the MATLAB code saved as : function [mean, stdev] = stat(x)
 * The next function highlights the capability to have multiple outputs:

% STAT Mean and standard deviation

%   For a vector x, stat(x) returns the mean of x;

%   [mean, stdev] = stat(x) both the mean and standard deviation.

%   For a matrix x, stat(x) acts columnwise.

[m n] = size(x);

if m == 1

m = n; % handle case of a row vector

end

mean = sum(x)/m;

stdev = sqrt(sum(x.^2)/m - mean.^2); Next, two function calls are made to. The first displays the aforementioned multiple outputs: >> [xm, xd] = stat(x)

xm =

0.6786

xd =

0.2938 And the second displays a single output (no square bracket required): >> xm = stat(x)

xm =

0.6786 Lastly, the  command is used to display the header for  : >> help stat

STAT Mean and standard deviation

For a vector x, stat(x) returns the mean of x;

[mean, stdev] = stat(x) both the mean and standard deviation.

For a matrix x, stat(x) acts columnwise.
 * The last function examples highlight the use of the  command to pass functions to other functions:

First, the MATLAB code for the function, which finds the zero of a passed function via bisection method: function [b, steps] = bisect(fun, x, tol)

%BISECT Zero of a function of one variable via the bisection method

%   bisect(fun,x) returns a zero of the function. fun is a string

%   containing the name of a real-valued MATLAB function of a

%   single real variable; ordinarily functions are defined in

%   M-files. x is a starting guess. The value returned is near

%   a point where fun changes sign. For example,

%   bisect('sin',3) is pi. Note the quotes around sin.

%

%   An optimal third input argument sets a tolerance for the

%   relative accuracy of the result. The default is eps.

%   An optional section output argument gives a matrix containing a

%   trace of the steps; the rots are of form [c f(c)].

% Initialization

if nargin < 3, tol = eps; end

trace = (nargout == 2);

if x ~= 0, dx = x/20; else, dx = 1/20; end

a = x - dx; fa = feval(fun,a);

b = x + dx; fb = feval(fun,b);

% Find change of sign.

while (fa > 0) == (fb > 0)

dx = 2.0*dx;

a = x - dx; fa = feval(fun,a);

if (fa > 0) ~= (fb > 0), break, end

b = x + dx; fb = feval(fun,b);

end

if trace, steps = [a fa; b fb]; end

%Main loop

while abs(b - a) > 2.0*tol*max(abs(b),1.0)

c = a + .5*(b-a); fc = feval(fun,c);

if trace, steps = [steps; [c fc]]; end

if (fb > 0) == (fc > 0)

b = c; fb = fc;

else

a = c; fa = fc;

end

end

And the function call to find the zero of the sin function near x = 2: >> bisect('sin',2)

ans =

3.1416  >> type eig
 * Finally, the primer notes the usefulness of the  command to identify the nature of functions:

'eig' is a built-in function. >> type vander

function A = vander(v)

%VANDER Vandermonde matrix.

%  A = VANDER(V) returns the Vandermonde matrix whose columns

%  are powers of the vector V, that is A(i,j) = v(i)^(n-j).

%

%  Class support for input V:

%     float: double, single

%  Copyright 1984-2004 The MathWorks, Inc.

%  $Revision: 5.9.4.1 $  $Date: 2004/07/05 17:01:29 $

n = length(v);

v = v;

A = ones(n,class(v));

for j = n-1:-1:1

A(:,j) = v.*A(:,j+1);

end >> type rank

function r = rank(A,tol)

%RANK  Matrix rank.

%  RANK(A) provides an estimate of the number of linearly

%  independent rows or columns of a matrix A.

%  RANK(A,tol) is the number of singular values of A

%  that are larger than tol.

%  RANK(A) uses the default tol = max(size(A)) * eps(norm(A)).

%

%  Class support for input A:

%     float: double, single

%  Copyright 1984-2004 The MathWorks, Inc.

%  $Revision: 5.11.4.3 $  $Date: 2004/08/20 19:50:33 $

s = svd(A);

if nargin==1

tol = max(size(A)') * eps(max(s));

end

r = sum(s > tol);

Part 13: Text strings, error messages, input
This section of the primer discusses the various methods of handling text in MATLAB.

 >> s = 'This is a test'
 * The first example shows the necessity of single quotes for defining a simple text string:

s =

This is a test  >> disp('this message is hereby displayed')
 * The next example features use of the  and   commands:

this message is hereby displayed >> error('Sorry, the matrix must be symmetric')

??? Sorry, the matrix must be symmetric Note that when the  command is used, the resulting output is displayed in red. <blockquote style="background: white; border: 1px solid rgb(153, 153, 153); width: 500px; padding: 1em;"> >> iter = input('Enter the number of iterations:  ')
 * The final example features text-based input:

Enter the number of iterations:  12

iter =

12

Part 14: Managing M-files
This section of the primer explains how to manage M-files.

Creating an M-file is done in three ways.
 * 1) From the MATLAB menu bar, select File -> New -> M-File
 * 2) Pressing Ctrl + N from the keyboard
 * 3) Right clicking in the Current Directory window and selecting New -> M-File

Three sample M-files were created to test each method: mfile.m, petals.m, fact.m. The files petals.m and fact.m are a script file and a function file, respectively, taken from tutorials in MATLAB's Help section. The code below displays the data entered into the files.

% This is an M-file. % An M-file script to produce      % Comment lines % "flower petal" plots theta = -pi:0.01:pi;               % Computations rho(1,:) = 2 * sin(5 * theta) .^ 2; rho(2,:) = cos(10 * theta) .^ 3; rho(3,:) = sin(theta) .^ 2; rho(4,:) = 5 * cos(3.5 * theta) .^ 3; for k = 1:4 polar(theta, rho(k,:))         % Graphics output pause end function f = fact(n) % Compute a factorial value. % FACT(N) returns the factorial of N, % usually denoted by N!
 * mfile.m:
 * petals.m:
 * fact.m:

% Put simply, FACT(N) is PROD(1:N). f = prod(1:n);

In order to edit an M-file after it has been created, the primer uses non-current commands to call the editor from the command line. An example of the correct command edit is shown below.

>> edit mfile

After this command has run, MATLAB opens Editor and displays the current version of the file where it can now be edited.

To simply display the contents of the file in the current window, the type and dbtype commands are used.

Commands:
 * type mfile - displays entire M-file
 * dbtype mfile - displays entire M-file with line numbers
 * dbtype mfile #:# - displays lines # through # of the M-file

Examples: >> type mfile

% This is an M-file. >> dbtype petals

1    % An M-file script to produce       % Comment lines 2    % "flower petal" plots 3    theta = -pi:0.01:pi;                % Computations 4    rho(1,:) = 2 * sin(5 * theta) .^ 2; 5    rho(2,:) = cos(10 * theta) .^ 3; 6    rho(3,:) = sin(theta) .^ 2; 7    rho(4,:) = 5 * cos(3.5 * theta) .^ 3; 8    for k = 1:4 9        polar(theta, rho(k,:))          % Graphics output 10       pause 11   end >> dbtype fact 1:3

1    function f = fact(n) 2    % Compute a factorial value. 3    % FACT(N) returns the factorial of N,

Working with directories
The current directory is the folder location on the hard drive where current files are being initialized from. The current directory should be displayed in a window in MATLAB.

Commands:
 * pwd OR cd - displays the current directory
 * cd .. - navigates the current directory to the one above it
 * cd ( 'directory ') - navigate the current directory to the specified one
 * dir OR ls - lists the files in the current directory in an array
 * dir *.m OR what - lists the M-files in the current directory in an array
 * delete filename - deletes a file from the directory

Examples: >> pwd

ans =

C:\Documents and Settings\...

>> cd

C:\Documents and Settings\...

>> cd .. >> cd ('C:\Documents and Settings\...') After navigating back to the original directory... >> dir

.        ..        fact.m    mfile.m   petals.m

>> ls

.        ..        fact.m    mfile.m   petals.m

>> dir *.m

fact.m   mfile.m   petals.m

>> what

M-files in the current directory C:\Documents and Settings\...

fact     mfile     petals

>> delete mfile.m >> what

M-files in the current directory C:\Documents and Settings\...

fact     petals

Part 15: Comparing efficiency of algorithms: flops, tic, toc
The first section of this part discusses flops. However, MATLAB no longer supports the counting of flops. Therefore, no commands with flops are able to be performed. Below shows the script of the flop fuunction provided by MATLAB.

function f = flops(x) %FLOPS Obsolete floating point operation count. %  Earlier versions of MATLAB counted the number of floating point %  operations. With the incorporation of LAPACK in MATLAB 6, this %  is no longer practical.

%  Copyright 1984-2004 The MathWorks, Inc. %   $Revision: 5.12.4.1 $  $Date: 2004/01/24 09:21:21 $

if (nargin < 1) || (x ~= 0) warning('MATLAB:flops:UnavailableFunction', ...       'Flop counts are no longer available.') end if nargout > 0 f = 0; end

The command including tic and toc are used to measure the elapsed time of an execution. They are timers that start and stop the clock before and after a statement.

Command: tic, statement, toc - displays the time required to execute the statement

Example: >> A = 1

A =

1

>> B = 1

B =

1

>> tic, x = A / B, toc

x =

1

Elapsed time is 0.000038 seconds.

The last command was computed multiple times. Elapsed time varied and was never less than 0.000035 seconds. Measuring efficiency with tic and toc are not reliable measurement of efficiency because elapsed time depends on how busy the computer is during execution.

Part 16: Output format
Displaying variables can be done in many ways. Output depends on how precise the variable needs to be. The format command adjusts this setting. The commands and examples are as follows.

Commands:
 * format - changes the output format to the default type of short
 * format type - changes the output format to the type specified

MATLAB provides the following information in tables in Help for the different types of formatting:

For floating-point variables
 * short - scaled fixed point format with 5 digits (default)
 * long - scaled fixed point format with 15 digits for double; 7 digits for single
 * short e - floating point format with 5 digits
 * long e - floating point format with 15 digits for double; 7 digits for single
 * short g - best of fixed or floating point with 5 digits
 * long g - best of fixed or floating point with 15 digits for double; 7 digits for single
 * short eng - engineering format that has at least 5 digits and a power that is a multiple of three
 * long eng - engineering format that has exactly 16 significant digits and a power that is a multiple of three

For all numeric variables
 * + - +, -, blank
 * bank - fixed dollars and cents
 * hex - hexadecimal (hexadecimal representation of a binary double-precision number)
 * rat - ratio of small integers

For all variables
 * compact - suppresses excess line feeds to show more output in a single screen*loose - adds linefeeds to make output more readable

Examples: >> A = 1.2345678910111213

A =

1.2346

>> format long; A

A =

1.23456789101112

>> format; A

A =

1.2346

>> format short e; A

A =

1.2346e+000

>> format long e; A

A =

1.234567891011121e+000

>> format short g; A

A =

1.2346

>> format long g; A

A =

1.23456789101112

>> format short eng; A

A =

1.2346e+000

>> format long eng; A

A =

1.23456789101112e+000

>> format +; A

A =

+

>> format bank; A

A =

1.23

>> format hex; A

A =

3ff3c0ca42c959f1

>> format rat; A

A =

100/81

>> format compact; A A = 100/81   >> format loose; A

A =

100/81

Part 17: Hardcopy
In order to obtain a copy of the commands and output of a session in MATLAB, MATLAB has a function called diary that directly copies the information displayed in the Workspace window into a file.

Commands:
 * diary - creates a file named diary that stores the output of the Workspace if no file name was specified
 * diary filename - creates a file with the name filename that stores the output of the Workspace
 * diary off - stops recording the output

Example:

What MATLAB outputs to Workspace: >> ls

.             fact.m         petals.m       ..             homework1.txt

>> diary record >> A = 1

A =

1

>> ls

.             fact.m         petals.m       ..             homework1.txt  record

>> diary off >> B = 2

B =

2

What the file record saves: A = 1

A =

1

ls

.             fact.m         petals.m       ..             homework1.txt  record

diary off

Part 18: Graphics
MATLAB can creat multi-dimensioned plots of functions, points, and other forms of data. In order to display these plots, certain commands must be called in order to output the correct display. The plots allow for great versatility with different formats of plots in a variety of colors and from two to three dimensions.

Planar plots
Planar plots graph functions and point in the x-y plane. Below is the basic form of the command and an example of how to implement it.

Command:

plot(x,y,string) - graphs vector y against vector x; string is a string of characters

The string may be omitted from the command so that the plot is a solid black line (plot(x,y)). Incorporating a string allows for dotted, dashed, and other forms of lines available in many colors. By typing in the command below, MATLAB displays the available formats as shown.

>> help plot

Available string possibilities (one element from any or all three columns): b    blue. point             -     solid g    green         o     circle             :     dotted r    red           x     x-mark             -. dashdot c    cyan          +     plus               --    dashed m    magenta       *     star             (none)  no line y    yellow        s     square k    black         d     diamond v    triangle (down) ^    triangle (up) <    triangle (left) >    triangle (right) p    pentagram h    hexagram

Examples:

Graphed as plots: >> figure(1); x = -4:0.01:4; y = sin(x); plot(x,y) >> figure(2); x = -1.5:0.01:1.5; y = exp(-x.^2); plot(x,y)

Graphed as functions function y = expnormal(x) y = exp(-x.^2); >> fplot('expnormal', [-1.5,1.5])
 * Created an M-file titled expnormal.m
 * Entered the data as shown below
 * Entered the command as shown below

Changing plot title and axis names and adding text to spots >> t = 0:0.001:2*pi; x = cos(3*t); y = sin(2*t); plot(x,y) >> title('Best Least Squares Fit') >> xlabel('X-axis') >> ylabel('Y-axis') >> gtext('The Spot')

Adding gridlines and changing the scale (continued from previous section) >> grid >> axis([-2,2,-2,2])

Multiple plots on on graph >> x = 0:0.01:2*pi; y1 = sin(x); y2 = sin(2*x); y3 = sin(4*x); plot(x,y1,x,y2,x,y3)

OR

>> x = 0:0.01:2*pi; Y = [sin(x)', sin(2*x)', sin(4*x)']; plot(x,Y) EDU>

Other types of planar plots include polar, bar, hist, quiver, compass, feather, rose, stairs, and fill.

Graphics hardcopy
To obtain a hardcopy of the current graphic the command print is used. This command will send the image to the default printer using predefined settings. These settings can be changed by using the printopt command.

The command print followed by a name can be used to print and save the graphic. If the name following the print command does not include a post script the appropriate post script will be assigned to the file. Several graphics can be saved to a single file and printed using the print -append filename command. If the append command is not used on an existing file, the existing file will be overwritten with the new graphic.

Graphics other then the current graphic can be printed and saved by use of the command print -deps -graphic filename. An example of this command is print -deps -f4 Lulz. The previous command will save figure 4 in file Lulz.eps.

3-D line plots
Matlab will produce plots in 3 dimensions using the command plot3. If the X, Y and Z coordinates are the desired coordinates the the command would be as follows, plot3(X,Y,Z). An example of a plot using this command is as follows, t=.01:.01:20*pi; x=cos(t); y=sin(t); z=t.^3; plot3(x,y,z), which creates the following helix:

The axis limits can then be determined using the axis command:

EDU>> axis

ans =

-1          1          -1           1           0      250000

3-D mesh and surface plots
Mesh plots can be created using the meshcommand. For example the command mesh(x) will create a mesh plot of the predetermined matrix x. Surface plots are created in a similar fashion using the surf command. Just as before the surf(x) command will create a surface plot of the predetermined matrix x.

In order to draw a graph of a function z=f(x,y) it is important to first define xx and yy. These will give partitions of the sides of the rectangle in which the graph is on. Using the command [x,y] = meshgrid(xx,yy); a matrix x and a matrix y are created. Each row of matrix x is equal to xx and it has a column length equal to the length of yy. Each column of matrix y is equal to yy. For example if one wanted to graph z=e-x 2-y2 over the square [-2,2]X[-2,2] the code would be as follows: [x,y]=meshgrid(-2:.2:2,-2:.2:2); z=exp(-x.^2-y.^2); mesh(z)

The shading of the surface plot can be changed with the shading command. The three choices are shading faceted, shading interp, or shading flat. The following is an example of the shading flat command:

The color of the shading can also be changed using one of the following preset color scheme commands: hsv, hot, cool, jet, pink, copper, flag, grey, or bone. For example colormap(hot)  will color the surface plot with the hot color scheme.

The command view allows one to set how the plot is to be viewed.

Matlab has several preset functions that demonstrate the surface plot feature. I few examples are: peaks, sphere, and cylinder. The following is an example of peaks:

Handle graphics
To see the properties of figure 1 enter the command set(1)  and gca,set(ans) . These properties describe almost all aspects of the plots. This system is called the handle graphics and is further described in the matlab user’s manual.

Part 19: Sparse matrix computations
Matlab is set to assume that any number in a matrix may be a number other then zero. Unfortunately, this assumption cost memory and computing time when it comes to numbers in a matrix that are known to be zero. This is why Matlab has the function sparse available. This function only saves the nonzero components of the matrix saving computing time and memory. For example:

EDU>> f=eye(3)

f =

1    0     0     0     1     0     0     0     1

EDU>> sparse(f)

ans =

(1,1)       1   (2,2)        1   (3,3)        1

EDU>> full(f)

ans =

1    0     0     0     1     0     0     0     1

Notice how the sparse command only shows the nonzero components and the full command shows the entire matrix. One can check the mode of a matrix my entering the command issparse(matrixname) . Typically sparse matrix are generated directly rather then applying the command sparse. To do this one would use the command spdiags. For example:

EDU>> m =6; EDU>> n=6; EDU>> e=ones(n,1); EDU>> d=-2*e; EDU>> t=spdiags([e,d,e],[-1,0,1],m,n)

t =

(1,1)      -2   (2,1)        1   (1,2)        1   (2,2)       -2   (3,2)        1   (2,3)        1   (3,3)       -2   (4,3)        1   (3,4)        1   (4,4)       -2   (5,4)        1   (4,5)        1   (5,5)       -2   (6,5)        1   (5,6)        1   (6,6)       -2

The sparse commands for eye, zeros, one, and randn are speye, sparse, spones, and sprandn respectively. Here is an example of each of these commands:

EDU>> speye(3)

ans =

(1,1)       1   (2,2)        1   (3,3)        1

EDU>> sparse(3)

ans =

(1,1)       3

EDU>> spones(3)

ans =

(1,1)       1

EDU>> sprandn(3)

ans =

(1,1)     -0.4326

Using the sparse command one can create a matrix listing only the nonzero components. An example of this is as follows:

EDU>> i=[1 2 3 4 4 4]; EDU>> j=[1 2 3 1 2 3]; EDU>> s=[5 6 7 8 9 10]; EDU>> S=sparse(i,j,s,4,3), full(S)

S =

(1,1)       5   (4,1)        8   (2,2)        6   (4,2)        9   (3,3)        7   (4,3)       10

ans =

5    0     0     0     6     0     0     0     7     8     9    10

Notice that the matrix is displayed both in the sparse mode and the full mode. The following is another example displayed only in the sparse mode.

EDU>> n=6; EDU>> e=floor(10*rand(n-1,1)); EDU>> E=sparse(2:n,1:n-1,e,n,n)

E =

(2,1)       9   (3,2)        2   (4,3)        6   (5,4)        4   (6,5)        8

It is important to note that any operation done on a full matrix will create a full matrix result while any operation done on a sparse matrix will create a sparse matrix result.

Class Introduction
The first week of lecture was used as an introduction to the class. Dr. Loc Vu-Quoc introduced himself, his wiki page, the course website and the course syllabus.

The course is structured in a way to encourage a collaborative setting to prepare students for similar situations in industry by having the students form groups of 5 or 6. Dr. Loc Vu-Quoc has also stated that he believes that students learn better by teaching, so he has encouraged the group members to try to teach parts of the material to each other. The first assignment for each group was to turn in a paper listing the group name, which should be 4-6 characters in length; the names of the group members, their UFID numbers and their newly created wiki user names, as described in the course syllabus.

First Reading Assignment
The following was the first reading assignment, assigned on Sep. 5, 2008.

Ch 4 (Trusses, Beams, Frame) Ch 1 (Big Picture): 1.1 Discretization 1.1.1 Plane Truss elements 1.2 Assembly of Element equations (Ex: 1.4 Five-bar trusses) 1.4 Element solution of model ralidity 1.4.1 Plane Truss elemnets

Trusses, Matrix Method
Lecture material for the class began with chapter 4 of the book.

Notation:
 * Global Node Number - a number inside a circle; designates a node for the whole structure.
 * Local Node Number - a number inside a square; designates a node for a specific element.
 * Element Number - a number inside a triangle; designates a specific element of the entire structure.

Here we see a truss with 2 elastic, deformable bars

Here we see the global free body diagram for the truss system.

The R's represent unknown reaction forces. The P is a known applied force. This FBD has 4 unknowns and 3 equations of equilibrium which makes it statically indeterminate.

2 FBDs of 2 bar elements:

Notation: fi(e) Ex: f2(1) represents the 2nd internal force in the 1st element.
 * i - ith internal force
 * (e) - element number
 * displacements are written in the same manner: di(e)

Since corresponding forces and displacements act along the same line, they can be represented by the same arrow.

Ex: f1(2),d1(2)

The next big step was to come up with Force-Displacement (FD) relationships.

Below we see the FD relationship of a 1 dimensional spring element with one end fixed followed by the FD relationship for a 1 dimensional spring element with both ends free.

Note: An elastic bar inclined in a plane is a 2 dimensional spring.

The FD relationship for the system can be written in matrix form with forces and displacements arranged as column matrices. The k matrix is called the stiffness matrix.

$$\binom {f1}{f2}=\begin{vmatrix} k & -k\\ -k &k \end{vmatrix} \binom{d1}{d2}$$

Some special cases to consider:

Case 1: An observer sits on node 1.

The observer would move with node 1 and the spring would seem to stretch by d2-d1.

f2 = k(d1-d2)

Case 2: An observer sits on node 2.

The observer would move with node 2.

f1= -f2 = -k(d2-d1)

Steps to Solve a Simple Truss
1. The global picture (description); at structure level are divided into: (1) global dofs (disp. dofs); disp. unknowns, and (2) global forces which usually known except for reactions.

Disp. dofs are partitioned into (1) a known part; e.g. fixed dofs, constraints, and (2) an unknown part; solved using FEM.

similarly for global forces:
 * a known part; applied forces
 * an unknown part; reaction forces

2. element picture
 * element dofs (either local or global coordinates)
 * element forces (either local or global coordinates)

3. global force-displacement
 * element stiffness matrices in global coordinates
 * element force matrices in global coordinates
 * assembly of element stiffness matrices and element force matrices into global force-displacement relationship: kd=F
 * k is NxN;d is Nx1;F is Nx1
 * N = # of known and unknown displacement dofs
 * "free-free" system, unconstrained, singular, determinate is 0

4. elimination of known dops to reduce the global force-displacement relationship
 * stiffness matrix is non-singular; therefore invertible
 * can solve the system of equations - kd=F
 * only known dofs left
 * k is MxM; d is Mx1;F is Mx1
 * M = # of unknown displacement dofs
 * k is non-singular; therefore k-1 exists
 * therefore d=k-1F

5.compute element forces from now known d
 * gives element stresses

6.compute reactions (unknown forces)

Specific Example

Element Length:
 * L(1)=4
 * L(2)=2

Young's Modulus:
 * E(1)=3
 * E(2)=5

X-sectional Area:
 * A(1)=1
 * A(2)=2

Inclination Angle:
 * o (1)=30 deg
 * o (2)=-45 deg

1)Global Picture:

-global dofs

To number the disp. dofs and global forces:
 * follow order of nodes
 * for each node: label x then y

It is possible to arrange global forces and disp. dofs in matrix form:

$$\begin{Bmatrix} f1\\ \vdots\\ f2 \end{Bmatrix}=\begin{vmatrix} k \end{vmatrix}\begin{Bmatrix} d1\\ \vdots\\ d2 \end{Bmatrix}$$

In this case k is a 6x6 matrix and f and d are 6x1 matrices.

This problem was not completed as of Sep. 5, 2008.

Contributing Team Members
The following students contributed to this report:

Aaron Fisher - Eml4500.f08.Lulz.fisher 11:46, 12 September 2008 (UTC)

Eric Layton -

Sam Miorelli - Eml4500.f08.lulz.abcd 08:03, 19 September 2008 (UTC)

Ben Mitchell - Eml4500.f08.Lulz.mitchell.bm 12:15, 19 September 2008 (UTC)

John Saxon - Eml4500.f08.Lulz.js 03:36, 19 September 2008 (UTC)

Andrew Strack - Eml4500.f08.lulz.strack 07:57, 19 September 2008 (UTC)

title: User:Eml4500.f08.Lulz.Layton.Eric/Hw1


text:
User talk:Eml4500.f08.Lulz.Layton.Eric

 Hello Eml4500.f08.Lulz.Layton.Eric, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. To get started, you may

 * Take a guided tour and learn to edit.
 * Visit a (kind of) random random project.
 * Browse everything on Wikiversity, or visit a portal corresponding to your educational level: pre-school, primary, secondary, tertiary, non-formal education.
 * Find out about research activities on Wikiversity.

 * Read an introduction for teachers and find out how to write an educational resource for Wikiversity.
 * Give feedback about your initial observations
 * Discuss Wikiversity issues or ask questions at the colloquium.
 * Chat with other Wikiversitans on #wikiversity-en.

And don't forget to explore Wikiversity with the links to your left. Be bold to contribute and to experiment with the sandbox or your userpage, and see you around Wikiversity! --JWSchmidt 00:54, 10 September 2008 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: User talk:Eml4500.f08.Lulz.Layton.Eric


text:
BCP/Solidago bicolor

Solidago bicolor

title: BCP/Solidago bicolor


text:
BCP/Solidago bicolor/Logs

2008 Logs

 * (no archived logs yet)

Recent Logs

 * Jomegat 01:17, 10 September 2008 (UTC)
 * Jomegat 21:37, 18 September 2008 (UTC)

title: BCP/Solidago bicolor/Logs


text:
User:Eas4200c.f08.blue.a/Lecture 4

 Introduction to Aerospace structures

The goals of aerospace structures is to design aircraft that are very light yet also strong. this is accomplished through the use of materials that have a high stiffness, high strength, and lightweight.

The stiffness of a material is determined by  $$E$$  The young's modulus of the material which is relates the stress and strain on the material through hooke's law  $$\sigma=E*\epsilon$$  hooke's law is a linear equation and the Young's modulus is the slope of the equation. This means for the higher the Young's modulus the faster the stress will increase meaning little deformation will be able to occur in the material before the yield stress is reached.

The strength of a material is determined by  $$\sigma_y $$, $$ \sigma_u$$  which are the yield stress and the ultimate stress respectively.

The higher the stresses that the material is able to handle before yielding the stronger the material.

Toughness is also considered in materials because it is the ability of the material to resist fracturing. Which means that a material with a high toughness would be able to resist fracturing very well. An example of a very stiff material but has a very low toughness would be glass.

Two aspects of aircraft design are the geometry and materials used. The geometry for the aircraft body is constructed by a thin wall shell design instead of an internal truss design. Aerodynamics also play a larger role in the geometry of the aircraft. Materials that are used need to be used to their full capacity to avoid more weight than necessary in the design. Also when able replace aluminum and titanium with fiber reinforced composites which will reduce weight by approximately thirty to forty percent.

Book pg 1-3

title: User:Eas4200c.f08.blue.a/Lecture 4


text:
User:Eas4200c.f08.aeris.krammer

Homework 1 Homework 2 Homework 3 Homework 4 Homework 5 Homework 6 Homework 7

Lecture Notes - Homework Problem Assignments

Nov 17 - Whitaker - Incomplete

Nov 19 - Nelson Caceres - Incomplete

Nov 21 - Magic One - Incomplete

Nov 24 - Magic One - Incomplete

Dec 1 - Anett - Incomplete

Dec 5 - Whitaker - Incomplete

Dec 8 - Anett - Incomplete

wikiversity vs webCT (E-learning) - all

Software used for wiki reports - all

matlab assignment- Jin Guan (complete), josh (buckling analysis)

title: User:Eas4200c.f08.aeris.krammer


text:
User talk:Eas4200c.f08.aeris.krammer

 Hello Eas4200c.f08.aeris.krammer, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. To get started, you may

 * Take a guided tour and learn to edit.
 * Visit a (kind of) random random project.
 * Browse everything on Wikiversity, or visit a portal corresponding to your educational level: pre-school, primary, secondary, tertiary, non-formal education.
 * Find out about research activities on Wikiversity.

 * Read an introduction for teachers and find out how to write an educational resource for Wikiversity.
 * Give feedback about your initial observations
 * Discuss Wikiversity issues or ask questions at the colloquium.
 * Chat with other Wikiversitans on #wikiversity-en.

And don't forget to explore Wikiversity with the links to your left. Be bold to contribute and to experiment with the sandbox or your userpage, and see you around Wikiversity! --JWSchmidt 02:05, 10 September 2008 (UTC)

title: User talk:Eas4200c.f08.aeris.krammer


text:
User:Eml4500.f08.gravy.bje

This is my wikipedia page for the Fall 2008 semester for EML4500

MATLAB BJE

HW2 Notes BJE

HW3 Notes BJE

HW4 Notes BJE

HW5 Notes BJE

HW6 Notes BJE

HW7 Notes BJE

title: User:Eml4500.f08.gravy.bje


text:
User:Eml4500c.f08.gravy.bje

Accessing MATLAB
After MATLAB is installed to the computer, it may be accessed either by clicking on a icon on the desktop, or if that icon was not created, by selecting the icon in the start menu. An alternate method to access MATLAB is to enter it into the system command which can also be found in the start menu

For convenience, MATLAB, as well as the local editor should both remain open in separate windows for any computer system that allows for multiple processes. Any questions in this area should be directed towards the computer manufacturer.

Entering Matrices
Matrices are the method by which MATLAB represents all variables. Single variables or interpreted as a 1 x 1 matrix, with no indicated direction. This is also known as a scalar quantity. A vector is represented by any matrix consisting of one column, or one row. All matrices are two dimensional and must consist of numerical values.

There are multiple methods by which to introduce a matrix into MATLAB including loading the matrix from a disk or file, inserting the matrix manually, or using a matrix that has been generated by another mathematical equation. The following two statements are examples of the correct syntax to generate a 3 x 3 matrix:

A = [1 2 3; 4 5 6; 7 8 9]

A= [ 1 2 3 4 5 6 7 8 9] The first example separates the values by spaces and the rows by semi-colons while the second separates the rows by lines.

To indicate an exponent, values must be entered in without spaces (i.e. 2.34e-5) for proper syntax. MATLAB also has the ability to interpret imaginary numbers using i and j. These values are also entered without spaces (i.e. 3+4i). If the values of i and j are assigned prior to their use as an imaginary value, a new value can be used by first setting it equal to the square root of negative one.

If a matrix is too long and tedious to enter manually it should be entered via an ASCII file from the local editor to avoid possible error from input. To load files in MATLAB, use the load command followed by the name of the file.

For example: load filename.ext If a user wishes to experiment with matrices of random numbers the rand, magic, and hilb functions provide a solution. The rand function creates a matrix of randomly generated numbers for a matrix with the same number of rows as columns. The magic function creates a magic square matrix. This is a particular type of matrix where the rows, columns, and diagonals have a common sum. The hilb function creates a Hilbert matrix.

Matrix and Array Operations
MATLAB has a variety of operations available including addition (+), subtraction (-), multiplication (*), power (^), conjugate transpose (‘), left division (\), and right division (/) all of which can be applied to both scalars and vectors. Order of operations applies.

Scalar Functions
There are some functions in MATLAB that were designed and created for scalar functions. These functions can still operate element-wise on matrices. Some common examples are sin, cos, tan, asin, acos, atan, exp, log, ln, rem (remainder), abs (absolute value), sqrt (square root)

Vector Functions
Unlike scalar functions, vector functions are, as their name hints, used on vectors (i.e. matrices or size m x n). These functions when used yield answers which are also in vector form. Some common examples of vector functions are max (max value), min (min value), sort (sort values), median, mean, std (standard deviation), sum, prod (product)

Matrix Functions
As mentioned above, matrices are used as a representation of variables in MATLAB. This is what makes the program such a useful tool. Some common examples of matrix functions are eig (eigenvalues), chol (choleski factorization), inv (inverse), hess (hessenberg form), det (determinant)

title: User:Eml4500c.f08.gravy.bje


text:
User:Eas4200c.f08.blue.a/Lecture 3

The Vision for EAS 4200c
The Big Picture

Wikipedia is part of the Mediawiki software. The Mediawiki software is used in many different programs and websites and allows for collaboration from all users from any location in the world.

Confidentiality

Because some students have expressed concern over having their last names in the wikipedia usernames, groups have the option of using letters (i.e. a,b,c,d,e) to identify their individual userpages.

Method of Work

Old Approach

The old approach which didn't utilize the Mediawiki software had a different grading scale. The old system had homework worth 10%, and each of the exams are worth 30%. For now, we will try the new method, where homework is worth 31%, and each exam is worth 23%. If at any point during the year, a majority of students feel like the new method doesn't work, we can revert to the old method. We will give it, "the old college try."

E-Learning

Dr. Vu-Quoc has decided not to use the e-learning system provided by UF for this class. He is not familiar with the software and feels that the Mediawiki software is perfect for the course plan.

Collaboration

This class involves collaboration among several groups. The first is collaboration among the students in the group. Next, is the collaboration among the class groups. Lastly is collaboration among all of the groups and the professor. By making all the class notes availiable to everyone, it will enhance the learning experience.

title: User:Eas4200c.f08.blue.a/Lecture 3


text:
User talk:Eml4500.f08.gravy.bje

 Hello Eml4500.f08.gravy.bje, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. To get started, you may

 * Take a guided tour and learn to edit.
 * Visit a (kind of) random random project.
 * Browse everything on Wikiversity, or visit a portal corresponding to your educational level: pre-school, primary, secondary, tertiary, non-formal education.
 * Find out about research activities on Wikiversity.

 * Read an introduction for teachers and find out how to write an educational resource for Wikiversity.
 * Give feedback about your initial observations
 * Discuss Wikiversity issues or ask questions at the colloquium.
 * Chat with other Wikiversitans on #wikiversity-en.

And don't forget to explore Wikiversity with the links to your left. Be bold to contribute and to experiment with the sandbox or your userpage, and see you around Wikiversity! --JWSchmidt 04:00, 10 September 2008 (UTC)

title: User talk:Eml4500.f08.gravy.bje


text:
User:Eml4500.f08.group/Matlab

Link to MATLAB Primer: http://apollo.mae.ufl.edu/~vql/courses/feem/matlab_primer_3rd.pdf

MATLAB PRIMER IS OFFLINE - FOUND SECONDARY LOCATION! http://www.uib.no/med/avd/miapr/arvid/MOD3/Matlab/matlab_primer_3rd.pdf Eas4200c.f08.carbon.clausen 04:01, 12 September 2008 (UTC)

To enter source code use:

Eas4200c.f08.carbon.clausen 18:31, 12 September 2008 (UTC)

=MATLAB PRIMER NOTES=

1. Accessing MALAB.
MATLAB can be accessed in a variety of ways. For example, most systems can access MATLAB by using the “matlab” system command. Similarly, MATLAB can be shut down using the internal MATLAB command of “quit” or “exit”. Since a MS Windows operation system is being used, MATLAB is accessed through the Windows start menu and closed via the red “X” icon in the upper right corner of the open MATLAB window.

Again, since Windows is being used, it will be convenient to keep both MATLAB and a text editor open in separate windows. Reasons for this will be discussed in section 14 (Managing M-files).

2. Entering matrices.
MATLAB functions via the use of rectangular matrices. Numbers, vectors, and variables can all be represented as a matrix with numbers coming in the form of a 1x1 matrix, vectors as 1xN / Nx1, and variable as an NxN matrix (N = 1,2,3…). Matrices can be generation by built in MATLAB functions, loaded from document files or external data files, and be entered directly as a list of elements. For example, typing into MATLAB generates a 3x3 matrix of numbers assigned to variable A.

MATLAB also accommodates the use of imaginary numbers in calculations. Complex matrices can be entering in one of two ways. Entering will generate the same complex matrix. The variable i and j denote complex values in MATLAB. New complex variable may be generated by entering into MATLAB. This will assign the variable ii equal to an imaginary number thus allowing for its use as a complex variable.

Loading large arrays into MATLAB is best accomplished by utilizing as ASCII file from a text editor. This file should consist of a rectangular array of matrix values. This file can then be loaded into MATLAB with the command “load file.ext” where file is the name of the file and .ext if the file extension.

Three built in MATALB commands can be used to generate matrices. Entering rand(n) or rand (m,n) will create a (n x n) or (m x n) matrix of random numbers. The magic(n) command will create a (n xn ) matrix in which all columns, rows, and diagonals have the same sum. Finally hilb(n) will create a (n x n) Hilbert matrix.

Individual matrix numbers can be accessed by entering A(2,3)). This command will find the numerical value assigned to the second row of column three in matrix A.

3. Matrix operations, array operations.
There are several matrix operations that are available for use in MATALB and they apply to both matrix and scalar operations. Should there be incompatibilities in the size of the matrices to be operated on, an error message will result. The following are available matrix operators.

Some of the above matrix operations do not operate entry-wise. The ones that do not (*, ^, /, and \) can be made to operate entry-wise by preceding them with a period.

4. Statements, expressions, and variable; saving a session.
MATLAB is an expression based language where expressions are composed of operators, and variable names. These expression usually take the form of “variable = expression.” The resulting matrix is then displayed on the screen and assigned a variable. Should no variable be assigned by the used, a standard variable of ans (answer) is assigned to the matrix.

Statements usually terminate at the end of a single line. In the case that a longer statement is necessary, three periods (…) followed by pressing return will continue the statement onto the next line. Conversely, several statements can be placed on a single line of code provided that each expression is separated by commas or semicolons. By placing a semicolon at the end of a line, the expression is evaluated but not printed to the screen.

It is important to note that MATLAB is case sensitive i.e. the variable “A” is not the same as variable “a”. Should it be necessary, typing the command “who” will list are current variable in the workspace and any variable may be removed by typing “clear” followed by the variable name that the user wishes to clear. Infinite loops can be broken by pressing “ctrl-break” on the keyboard

All data and variable names are lost whenever MATLAB is exited unless the save command is used. Using this command will restore the workspace to its previous version the next time MATALB is opened.

For Loop
For loop syntax example, to produce a certain n-vector for a given n:

or can be written:

 * Note: x = [] creates an empty matrix

The for statement permits any matrix to be used instead of 1:n. The variable consecutively assumes the value of each column of the matrix. The following example shows this syntax as it sums all the entries of matrix A by adding its column sums.

While loop
General form:

The statements will be repeated continuously while the relation is true. Once the relation is no longer true the loop ends.

An example for a given number a, will compute and display the smallest nonnegative integer n, such that 2^n >= a:

 * Note: The semicolon after the statement keeps the values of n from printing on screen until after the loop is over and then the program calls to print n on the screen.

If statement
General form:

The statements are executed only if the relation is true.

Multiple branching is also possible as shown in the following example:

Relations
The relational operators in MATLAB are:

 * Note: = is used in an assignment statement while == is used in a relation

Relations may be connected or qualified by the following logical operators:

When applied to scalars a relation is just the scalar 1 (if true) or 0 (if false). Similarly for matrices of the same size a relation is a matrix of 1’s or 0’s. When a relation between matrices is interpreted by a while or if to be true each entry of the relation matrix must be nonzero.

Examples:
To execute statement 	when matrices A and B are equal:

To execute statement when A and B are not equal:

Or

 * Note: The above example does not work with the syntax:

This will not give the intended result because statement would only execute if each of the corresponding entries of A and B differ.

7. Scalar functions
A scalar function is one whose range is one dimensional and is made up of one or more variables. In MATLAB scalar functions generally operate on scalars, but will operate element-wise on matrices. some of the more common functions are:

8. Vector functions
A vector function is one whose range is three or n-dimensional. In MATLAB these functions generally operate on a vector. When applied to matrices in a column-by-column fashion to give you a row vector. If row-by-row action is desired it can be generated using the transpose. Some of the more common of these functions are:

10. Command line editing and recall
Editing the command line is very simple in MATLAB. Positioning of the cursor can be done with the left and right arrows. Backspace and Delete can be used to remove characters to the left and right of the cursor respectively. Edits can also be made to previous commands by using the up and down arrows to scroll through the commands to find the one you wish to edit and execute again. These edits work best for small projects and revisions.

11. Submatrices and colon notation
Colon notation is used to produce vectors and to reference submatrices. Colon Notation in addition to subscripting by key vectors are necessary to effectively manipulate matrices. They can also be used in place of loops to make the code more readable and simple. The formula for the colons is initial value: increment: terminating number. An example of this is: The Incrementing value can also be left out, causing the default of one o be used, such as: Colon Notation can be used to obtain submatrices of a matrix. An example of this is:

12 M-files: script files, function files
“M-files” are an integral part of MATLAB as they are files which can execute a sequence of statements stored in diskfiles – they are designated by the extension “.m” appended to the end of the filename. “M-files” can be broken down into two distinct forms: script files and function files.

Script files:

Script files are “M-files” which can contain a number MATLAB commands which can be executed by calling the script file by name. The advantage of a script file is evident; a single MATLAB command will actually execute a series of previously developed commands. Script files can be used to easily input data into a function, such as a matrix, which can help reduce entry errors. It is important to note that script file variables are global; and, the effect of the global variables contained in script files is that variables of the same name in the current MATLAB window will be altered by running the script command.

Function files:

Function files are another type of “M-file” similar to a script file, but allowing for (in certain ways) more control over how MATLAB handles an occurrence of this file type. Function files allow users to create their own functions in MATLAB, which can be used as any ordinary MATLAB function would (such as how “sqrt” is a MATLAB function that takes the square root of a number or of the value of a variable). A key difference between function files and script files is that variables in function files can be made either global or local – meaning that local variables can be created that pertain only to the function file (and thus a variable with the same name in a current MATLAB session would be unaffected by a call to the function file).

13 Text Strings, Error Messages and Input
Text strings are variables that contain a series, string, of characters. They are created by assigning text in single quotes to a variable name as exemplified below.

The function disp displays text strings.

However, the function error is better suited for displaying error messages as it also aborts execution of an M-file.

The user can be prompted to enter data during runtime of an M-file with the function input. This function assigns user input to it's return value. The return key denotes end of user input.

14 Managing M-Files
MATLAB has the ability to execute system commands without exiting MATLAB with the !-feature. Precede any system command with '!', for example.

This allows you to edit M-files without exiting MATLAB. For modern computers using a graphical user interface, simply opening the text editor in a new window is much simpler.

MATLAB also has a variety of debugging tools for M-files. Type help dbtype or see the last section for more details.

In MATLAB, the pwd command returns the name of the present working directory. dir or ls will list it's contents. If you only wish to see the M-files in the working directory use the what command. delete can be used to delete a file and type shows a M-file on the screen. These duplicate many common system commands while avoiding the use of the '!'.

Use the why command for entertainment

To use M-Files they must be in a directory accessible to MATLAB. M-Files in the current working directory are always accessible, as are M-file in a subdirectory of the home directory on most network installations. To see a list of directories currently in MATLAB's search path, or add and delete directories from the search path, use the path command.

15 Comparing efficiency of algorithms: Flops, tic and toc
MATLAB provides two method for measuring the efficiency of an algorithm. These are the number of floating point calculations (flops) and the elapse time it took to preform the algorithm. Note however that modern computers are time sharing machines and so elapse time may not be a reliable measure of efficiency. The computer may be busy performing another task in the middle of yours, adding to your task's time.

To measure elapse time, use the tic and toc commands. tic starts the time while toc returns the elapse time since tic was called. For example:

To measure the number of floating point calculations, use the flops and flops(0) commands. flops(0) resets the flop counter to zero and flops returns the current flop count. For example:

16 Output format
The precision of the displayed output can be controlled with the format command. This doesn't effect the computations themselves, which are always done in double precision. The format chosen from the table below remains in effect until changed.

additionally the command format compact will suppress blank lines while format loose will unsurpress blank lines. These do not effect which of the other format commands are active.

17 Hard copy
Command:  filename

This command pulls up the hardcopy and copies the content excluding graphics to that file, and will go to a default file if no filename is given. It continues to copy to the file until you command it to  or.

18 Graphics
MATLAB plots curves, 3D plots of curves , #D mesh surface plots , and 3D faceted surface plots. allows you to preview these features.

Planar plots
The command  creates an x-y plot as shown below the format for the range is 'lower rang:meshsize: upper range'.

Figures can be suppressed or exposed as the "current" figure by the command according to its figure number, and command   will give you the number of the current figure.

To make graphs, first put a function in an M-file then command it open with a domain:

Parametric graphs can also be defined as shown:

To enter text in the graph, follow these commands:

title of graph x-axis label y-axis label text on graph (placement defined by mouse) text position at specific coordinates places grid on the graph axis limits makes standard axis for all graphs auto-scaling shows current scaling for vector v puts same scale on both axes puts same scale and tic marks on both axes turns off both axis scaling and tic marks turns on both axis scaling and tic marks

Put the  commands after the   command.

To make multiple plots on a graph the format may be one of the two as follows

You can also command  to freeze the current plot and from there superimpose another plot on the same graph. This can be turned off with. To make line types use the codes: solid(-), dashed (--), dotted, dashdot (-.). To make marktypes, use the codes: point(.), plus (+), star (*), circle (o), x-mark (x). To make colors, use the codes: yellow(y), magent(m), cyan(c), red(r), green(g), blue(b), white(w), black(k). An example is a green dotted line:.

Several other features are:

Graphics hardcopy
To send the graphics to the printer, command, while   filename saves the figure to the specified format or to a default format if not specified.

3-D line plots
An example format of a 3-D line plot is as follows:

A 3-D graph has all the same commands plus.

3-D mesh and surface plots
3-D mesh plots shows a plots of matrix z with the command. A surface plot is controlled by. To obtain a mesh graph of a function over a rectangle, an example is as follows:

The shading can be  and are entered after the   command. Color profiles may be:.

Handle Graphics
To see a more complete list of the options to control a graph enter  and.

19 Sparse matrix computations
MATLAB generally assumes a matrix is dense, meaning that there is a possibility that any entry in the matrix could be non-zero. When a matrix has enough zero entries calculation time could be reduced and less memory will be needed to store the non-zero entries of the matrix. For this reason solutions to lager problems could be possible. MATLAB takes advantage of this by having two storage modes with the following functions: full and sparse.

The Following commands are used to create sparse matrices:

title: User:Eml4500.f08.group/Matlab


text:
Talk:Gender

September 2008 Boss’ Gender Impacts Employee Stress Levels

title: Talk:Gender


text:
Words of peace

 * A World of Peace, Love and Happiness
 * peaceflag

Some of the worlds languages with (between the brackets) an english way of writing the word, peace.

title: Words of peace


text:
Topic talk:Food science

http://www.eurekalert.org/pub_releases/2008-09/sfgm-fpb090808.php

http://www.eurekalert.org/pub_releases/2008-09/sfgm-fss090808.php

http://www.eurekalert.org/pub_releases/2008-09/sfgm-cgf090708.php

http://www.sciencedaily.com/releases/2008/09/080909204557.htm Emesee 02:41, 12 September 2008 (UTC)

title: Topic talk:Food science


text:
Topic talk:Synthetic biology

http://blog.wired.com/wiredscience/2008/09/biologists-on-t.html

title: Topic talk:Synthetic biology


text:
User talk:Synergy

Assistant teacher program
I had to revoke your changes to Assistant teacher course/Individual curriculum/Computer science, Assistant teacher course/Individual curriculum/Journalism and Assistant teacher course/Individual curriculum/Science; apparently you didn't notice they are included into Assistant teacher course/Individual curriculum/handout/Academic topics. It doesn't make sense for them to have their own reference lists. Thank's for trying to help. --fasten 06:38, 10 September 2008 (UTC)

title: User talk:Synergy


text:
How to use SPSS/Graphing

Removing background colour and borders
In SPSS output:
 * 1) Double-click the chart to go into the chart editor
 * 2) R.click - properties
 * 3) Click on fill - then the white box with a red line through it (to get rid of any background colour; this won't be actioned until Apply is clicked later)
 * 4) Click on border - then the white box with a red line through it
 * 5) Apply, then close out of the Chart Editor

title: How to use SPSS/Graphing


text: Category:Historical Subjects by Period

title: Category:Historical Subjects by Period


text: Category:Historical Subjects by Area

title: Category:Historical Subjects by Area


text: Category:North American History

title: Category:North American History


text: Category:19th Century History

title: Category:19th Century History


text: Category:History by country

title: Category:History by country


text: Category:United States History

title: Category:United States History


text: Category:20th Century History

title: Category:20th Century History


text: Category:Battles

title: Category:Battles


text: Category:History of Asia

title: Category:History of Asia


text: Category:14th Century History

title: Category:14th Century History


text: Category:Medieval History

title: Category:Medieval History


text:
User:Eml4500.f08.lulz.strack/hw1

Part 14: Managing M-files
This section of the primer explains how to manage M-files.

Creating an M-file is done in three ways.
 * 1) From the MATLAB menu bar, select File -> New -> M-File
 * 2) Pressing Ctrl + N from the keyboard
 * 3) Right clicking in the Current Directory window and selecting New -> M-File

Three sample M-files were created to test each method: mfile.m, petals.m, fact.m. The files petals.m and fact.m are a script file and a function file, respectively, taken from tutorials in MATLAB's Help section. The code below displays the data entered into the files.

% This is an M-file. % An M-file script to produce      % Comment lines % "flower petal" plots theta = -pi:0.01:pi;               % Computations rho(1,:) = 2 * sin(5 * theta) .^ 2; rho(2,:) = cos(10 * theta) .^ 3; rho(3,:) = sin(theta) .^ 2; rho(4,:) = 5 * cos(3.5 * theta) .^ 3; for k = 1:4 polar(theta, rho(k,:))         % Graphics output pause end function f = fact(n) % Compute a factorial value. % FACT(N) returns the factorial of N, % usually denoted by N!
 * mfile.m:
 * petals.m:
 * fact.m:

% Put simply, FACT(N) is PROD(1:N). f = prod(1:n);

In order to edit an M-file after it has been created, the primer uses non-current commands to call the editor from the command line. An example of the correct command edit is shown below.

>> edit mfile

After this command has run, MATLAB opens Editor and displays the current version of the file where it can now be edited.

To simply display the contents of the file in the current window, the type and dbtype commands are used.

Commands:
 * type mfile - displays entire M-file
 * dbtype mfile - displays entire M-file with line numbers
 * dbtype mfile #:# - displays lines # through # of the M-file

Examples: >> type mfile

% This is an M-file. >> dbtype petals

1    % An M-file script to produce       % Comment lines 2    % "flower petal" plots 3    theta = -pi:0.01:pi;                % Computations 4    rho(1,:) = 2 * sin(5 * theta) .^ 2; 5    rho(2,:) = cos(10 * theta) .^ 3; 6    rho(3,:) = sin(theta) .^ 2; 7    rho(4,:) = 5 * cos(3.5 * theta) .^ 3; 8    for k = 1:4 9        polar(theta, rho(k,:))          % Graphics output 10       pause 11   end >> dbtype fact 1:3

1    function f = fact(n) 2    % Compute a factorial value. 3    % FACT(N) returns the factorial of N,

Working with directories
The current directory is the folder location on the hard drive where current files are being initialized from. The current directory should be displayed in a window in MATLAB.

Commands:
 * pwd OR cd - displays the current directory
 * cd .. - navigates the current directory to the one above it
 * cd ( 'directory ') - navigate the current directory to the specified one
 * dir OR ls - lists the files in the current directory in an array
 * dir *.m OR what - lists the M-files in the current directory in an array
 * delete filename - deletes a file from the directory

Examples: >> pwd

ans =

C:\Documents and Settings\...

>> cd

C:\Documents and Settings\...

>> cd .. >> cd ('C:\Documents and Settings\...') After navigating back to the original directory... >> dir

.        ..        fact.m    mfile.m   petals.m

>> ls

.        ..        fact.m    mfile.m   petals.m

>> dir *.m

fact.m   mfile.m   petals.m

>> what

M-files in the current directory C:\Documents and Settings\...

fact     mfile     petals

>> delete mfile.m >> what

M-files in the current directory C:\Documents and Settings\...

fact     petals

Part 15: Comparing efficiency of algorithms: flops, tic, toc
The first section of this part discusses flops. However, MATLAB no longer supports the counting of flops. Therefore, no commands with flops are able to be performed. Below shows the script of the flop fuunction provided by MATLAB.

function f = flops(x) %FLOPS Obsolete floating point operation count. %  Earlier versions of MATLAB counted the number of floating point %  operations. With the incorporation of LAPACK in MATLAB 6, this %  is no longer practical.

%  Copyright 1984-2004 The MathWorks, Inc. %   $Revision: 5.12.4.1 $  $Date: 2004/01/24 09:21:21 $

if (nargin < 1) || (x ~= 0) warning('MATLAB:flops:UnavailableFunction', ...       'Flop counts are no longer available.') end if nargout > 0 f = 0; end

The command including tic and toc are used to measure the elapsed time of an execution. They are timers that start and stop the clock before and after a statement.

Command: tic, statement, toc - displays the time required to execute the statement

Example: >> A = 1

A =

1

>> B = 1

B =

1

>> tic, x = A / B, toc

x =

1

Elapsed time is 0.000038 seconds.

The last command was computed multiple times. Elapsed time varied and was never less than 0.000035 seconds. Measuring efficiency with tic and toc are not reliable measurement of efficiency because elapsed time depends on how busy the computer is during execution.

Part 16: Output format
Displaying variables can be done in many ways. Output depends on how precise the variable needs to be. The format command adjusts this setting. The commands and examples are as follows.

Commands:
 * format - changes the output format to the default type of short
 * format type - changes the output format to the type specified

MATLAB provides the following information in tables in Help for the different types of formatting:

For floating-point variables
 * short - scaled fixed point format with 5 digits (default)
 * long - scaled fixed point format with 15 digits for double; 7 digits for single
 * short e - floating point format with 5 digits
 * long e - floating point format with 15 digits for double; 7 digits for single
 * short g - best of fixed or floating point with 5 digits
 * long g - best of fixed or floating point with 15 digits for double; 7 digits for single
 * short eng - engineering format that has at least 5 digits and a power that is a multiple of three
 * long eng - engineering format that has exactly 16 significant digits and a power that is a multiple of three

For all numeric variables
 * + - +, -, blank
 * bank - fixed dollars and cents
 * hex - hexadecimal (hexadecimal representation of a binary double-precision number)
 * rat - ratio of small integers

For all variables
 * compact - suppresses excess line feeds to show more output in a single screen*loose - adds linefeeds to make output more readable

Examples: >> A = 1.2345678910111213

A =

1.2346

>> format long; A

A =

1.23456789101112

>> format; A

A =

1.2346

>> format short e; A

A =

1.2346e+000

>> format long e; A

A =

1.234567891011121e+000

>> format short g; A

A =

1.2346

>> format long g; A

A =

1.23456789101112

>> format short eng; A

A =

1.2346e+000

>> format long eng; A

A =

1.23456789101112e+000

>> format +; A

A =

+

>> format bank; A

A =

1.23

>> format hex; A

A =

3ff3c0ca42c959f1

>> format rat; A

A =

100/81

>> format compact; A A = 100/81   >> format loose; A

A =

100/81

Part 17: Hardcopy
In order to obtain a copy of the commands and output of a session in MATLAB, MATLAB has a function called diary that directly copies the information displayed in the Workspace window into a file.

Commands:
 * diary - creates a file named diary that stores the output of the Workspace if no file name was specified
 * diary filename - creates a file with the name filename that stores the output of the Workspace
 * diary off - stops recording the output

Example:

What MATLAB outputs to Workspace: >> ls

.             fact.m         petals.m       ..             homework1.txt

>> diary record >> A = 1

A =

1

>> ls

.             fact.m         petals.m       ..             homework1.txt  record

>> diary off >> B = 2

B =

2

What the file record saves: A = 1

A =

1

ls

.             fact.m         petals.m       ..             homework1.txt  record

diary off

Part 18: Graphics
MATLAB can creat multi-dimensioned plots of functions, points, and other forms of data. In order to display these plots, certain commands must be called in order to output the correct display. The plots allow for great versatility with different formats of plots in a variety of colors and from two to three dimensions.

Planar plots
Planar plots graph functions and point in the x-y plane. Below is the basic form of the command and an example of how to implement it.

Command:

plot(x,y,string) - graphs vector y against vector x; string is a string of characters

The string may be omitted from the command so that the plot is a solid black line (plot(x,y)). Incorporating a string allows for dotted, dashed, and other forms of lines available in many colors. By typing in the command below, MATLAB displays the available formats as shown.

>> help plot

Available string possibilities (one element from any or all three columns): b    blue. point             -     solid g    green         o     circle             :     dotted r    red           x     x-mark             -. dashdot c    cyan          +     plus               --    dashed m    magenta       *     star             (none)  no line y    yellow        s     square k    black         d     diamond v    triangle (down) ^    triangle (up) <    triangle (left) >    triangle (right) p    pentagram h    hexagram

Examples:

Graphed as plots: >> figure(1); x = -4:0.01:4; y = sin(x); plot(x,y) >> figure(2); x = -1.5:0.01:1.5; y = exp(-x.^2); plot(x,y)

Graphed as functions function y = expnormal(x) y = exp(-x.^2); >> fplot('expnormal', [-1.5,1.5])
 * Created an M-file titled expnormal.m
 * Entered the data as shown below
 * Entered the command as shown below

Changing plot title and axis names and adding text to spots >> t = 0:0.001:2*pi; x = cos(3*t); y = sin(2*t); plot(x,y) >> title('Best Least Squares Fit') >> xlabel('X-axis') >> ylabel('Y-axis') >> gtext('The Spot')

Adding gridlines and changing the scale (continued from previous section) >> grid >> axis([-2,2,-2,2])

Multiple plots on on graph >> x = 0:0.01:2*pi; y1 = sin(x); y2 = sin(2*x); y3 = sin(4*x); plot(x,y1,x,y2,x,y3)

OR

>> x = 0:0.01:2*pi; Y = [sin(x)', sin(2*x)', sin(4*x)']; plot(x,Y) EDU>

Other types of planar plots include polar, bar, hist, quiver, compass, feather, rose, stairs, and fill.

title: User:Eml4500.f08.lulz.strack/hw1


text: Category:Ancient History

title: Category:Ancient History


text: Category:History of Greece

title: Category:History of Greece


text:
Help:Starting to learn on wikiversity

We describe some Wikiversity learning flows for beginners.

 * You want to learn something with Wikiversity.
 * You come to http://wikiversity.org or http://en.wikiversity.org
 * You go to the search box on the upper left corner
 * You enter the topic/subject that you want to learn: the Mediawiki engine that powers Wikiversity would return either
 * a learning resource with the title (if it exists)
 * a list of resources which match your entry
 * You start participating in the community learning around the said resource(s), making use of the hyperlinks to find more resources; or you may create an alternative if you don't like it (in wikimedia, we often use simple and natural English title, so that it can be embedded in a sentence, e.g. use study guide for Shakespeare's tragedy of Hamlet instead of study guide:Hamlet (Shakespeare) - but that is up to your personal taste;  take some care to make sure that the title is sufficiently unambiguous)
 * You use Wikiversity to
 * collect on-line or on-paper resources, including text, images, pdf files, audio, etc
 * convene your learning community

title: Help:Starting to learn on wikiversity


text: Category:Meta Categories in History

title: Category:Meta Categories in History


text: Category:History of Africa

title: Category:History of Africa


text: Category:Historiography

title: Category:Historiography


text:
Category talk:Historiography

I'm placing this in category:History (instead of category:Historical Subjects by Topic) as I consider it particularly important to the subject. The Jade Knight 09:44, 10 September 2008 (UTC)

title: Category talk:Historiography


text: Category:History of Japan

title: Category:History of Japan


text:
Category:History of Philosophy

pt:Categoria:História da Filosofia

title: Category:History of Philosophy


text:
Wikiversity:Browse/By resource name

 You can browse all of Wikiversity's resources sorted by name, including pages not otherwise categorized.

title: Wikiversity:Browse/By resource name


text: Category:History of Ireland

title: Category:History of Ireland


text: Category:History of Nepal

title: Category:History of Nepal


text: Category:History of Physics

title: Category:History of Physics


text:
User talk:Vince~enwikiversity

You still working on this? The Jade Knight 10:29, 10 September 2008 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Vince. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Vince~enwikiversity that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 00:12, 18 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 06:24, 19 April 2015 (UTC)

title: User talk:Vince~enwikiversity


text:
User talk:Saberwing~enwikiversity

 Hello Saberwing, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. To get started, you may

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 * Chat with other Wikiversitans on #wikiversity-en.

And don't forget to explore Wikiversity with the links to your left. Be bold to contribute and to experiment with the sandbox or your userpage, and see you around Wikiversity! --The Jade Knight 10:34, 10 September 2008 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Saberwing. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Saberwing~enwikiversity that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:53, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 06:21, 19 April 2015 (UTC)

title: User talk:Saberwing~enwikiversity


text:
Assistant teacher course/Mentoring assistant teachers

A mentoring program for assistant teacher trainees
...


text:
University of Florida/Eml4500/f08.FEABBQ/9-5 Notes

In progress -Billy


text:
User:Eas4200c.f08.aero.kurth

William Kurth

title: User:Eas4200c.f08.aero.kurth


text:
MediaWiki talk:Longpagewarning

Looks good; thanks DarkLama
The heading says it all :). -- Jtneill - Talk - c 12:00, 10 September 2008 (UTC)

Longpagewarning is deprecated
See w:MediaWiki_talk:Longpagewarning and mw:Special:Code/MediaWiki/77148. --mikeu talk 20:06, 26 October 2019 (UTC)

title: MediaWiki talk:Longpagewarning


text:
Template talk:Rtlinks

What does this template do?
I'm curious about what this template does (and how it works). I found it used at Help:Lecture. -- Jtneill - Talk - c 12:08, 10 September 2008 (UTC)
 * I was curious too. So I looked at the history to see who created it. And found my answer. I'm kind of really slow today! --McCormack 12:14, 10 September 2008 (UTC)

title: Template talk:Rtlinks


text:
User talk:Eas4200c.f08.aero.kurth

 Hello Eas4200c.f08.aero.kurth, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. To get started, you may

 * Take a guided tour and learn to edit.
 * Visit a (kind of) random random project.
 * Browse everything on Wikiversity, or visit a portal corresponding to your educational level: pre-school, primary, secondary, tertiary, non-formal education.
 * Find out about research activities on Wikiversity.

 * Read an introduction for teachers and find out how to write an educational resource for Wikiversity.
 * Give feedback about your initial observations
 * Discuss Wikiversity issues or ask questions at the colloquium.
 * Chat with other Wikiversitans on #wikiversity-en.

And don't forget to explore Wikiversity with the links to your left. Be bold to contribute and to experiment with the sandbox or your userpage, and see you around Wikiversity! --JWSchmidt 12:13, 10 September 2008 (UTC)

title: User talk:Eas4200c.f08.aero.kurth


text:
User talk:Dreamsjoint

 Hello Dreamsjoint, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. To get started, you may

 * Take a guided tour and learn to edit.
 * Visit a (kind of) random random project.
 * Browse everything on Wikiversity, or visit a portal corresponding to your educational level: pre-school, primary, secondary, tertiary, non-formal education.
 * Find out about research activities on Wikiversity.

 * Read an introduction for teachers and find out how to write an educational resource for Wikiversity.
 * Give feedback about your initial observations
 * Discuss Wikiversity issues or ask questions at the colloquium.
 * Chat with other Wikiversitans on #wikiversity-en.

And don't forget to explore Wikiversity with the links to your left. Be bold to contribute and to experiment with the sandbox or your userpage, and see you around Wikiversity! --JWSchmidt 12:15, 10 September 2008 (UTC)

title: User talk:Dreamsjoint