implement iterations on MATLAB

sandy.bridge

Hello all,
I am trying to play around with MATLAB so I can become familiar with it. I have absolutely no programming experience, si it's a bit confusing for me. I have this formula:
[tex]v(t)=10(1-e^{-t})[/tex]
and I want to implement iterations on MATLAB for 0<=t<=5.

I understand that I need to start "for loop", but I'm not entirely sure how to go about it. I know to start it,
"for i=0:n"

Any suggestions and explanations?

Number Nine

Do you mean that you want to apply that function to each value of t from 1 to 5? There's no need to use a for loop.

t = 1:5;
v = 10*(1 - e.^(-t))

jhae2.718

Try this:

Code:

t = linspace(0, 5, 1000); % Produces 1000 data points linearly spaced on [0,5].
v = 10*(1 - exp(-t));

v will then be in your workspace and you can do anything with it. For plotting, the more points you use the better the plot will be.

In MATLAB, you should always prefer using vectors to for loops, e.g. use this:

Code:

x = 0:.01:100;
y = x .^ 2;

instead of:

Code:

% BAD !!!
x = 0:.01:100;
for i = 1:length(x);
    y(i) = x(i) .^ 2;
end

Here is a quick program that tests the speed of a for loop versus a vector operation:

Code:

t = cputime;
e = tic;
x = 0:.01:1000000;
for i = 1:length(x);
    y(i) = x(i) .^ 2;
end
fprintf('for: cputime: %f elapsed: %f \n', [cputime - t, toc(e)]);
t = cputime;
e = tic;
x = 0:.01:1000000;
y = x .^ 2;
fprintf('vec: cputime: %f elapsed: %f \n', [cputime - t, toc(e)]);

On my computer it outputs:

Code:

for: cputime: 12.850000 elapsed: 12.723039 
vec: cputime: 1.270000 elapsed: 1.395663

As you can see, even with the small example, MATLAB is more efficient using vectors than loops.

sandy.bridge

Can you guys recommend a good book for beginners? I was also attempting to implement Euler's method for differentials.

jhae2.718

I don't have any experience with MATLAB books, but the MathWorks documentation is invaluable: http://www.mathworks.com/help/techdoc/

To ask questions, try MATLAB Answers: http://www.mathworks.com/matlabcentral/answers/

Additionally, they have a series of MATLAB exercises you can try: http://www.mathworks.com/matlabcentral/cody

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Number Nine	Do you mean that you want to apply that function to each value of t from 1 to 5? There's no need to use a for loop. t = 1:5; v = 10*(1 - e.^(-t))

sandy.bridge	implement iterations on MATLAB Can you guys recommend a good book for beginners? I was also attempting to implement Euler's method for differentials.

jhae2.718 Blog Entries: 9 Recognitions: Gold Member	I don't have any experience with MATLAB books, but the MathWorks documentation is invaluable: http://www.mathworks.com/help/techdoc/ To ask questions, try MATLAB Answers: http://www.mathworks.com/matlabcentral/answers/ Additionally, they have a series of MATLAB exercises you can try: http://www.mathworks.com/matlabcentral/cody