apply "IF" condition to a matrix whitout loop

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Jonathan Roy 2013-11-28

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评论： Roger Stafford 2013-11-28

Hi!

It is possible to use matrix operation power with "if" condition?? I want to apply "if" conditionto all value of the matrix how agree the condition with out creating a for loop or multi "if" condition

Ex: here an simple exemple I don't want to put it inside "for" loop

x = [1,2] y = [100,35]

if x>1 x = 0; else x = x .* y^2; end

In my original code "x" and "y" are huge and I try to optimize the speed

Thank you!!

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Roger Stafford 2013-11-28

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That won't work with 'if'. It won't come true unless all the elements are negative. Use logical indexing.

 t = x>1;
 x(t) = x(t).*y(t).^2;

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Jonathan Roy 2013-11-28

It's always a pleasure to see answers popping so fast! It work so fine!!

Thank you for your help!!

Roger Stafford 2013-11-28

Thanks, Jos. I guess I'm not fully awake yet.

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MATLAB Language Fundamentals Loops and Conditional Statements

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