If Condition with array of elements

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Uday padidela on 26 Sep 2014
Answered: David Young on 28 Sep 2014
Can anyone help me how to write this condition
if (ra >= 1.12246*sigma)
uw=0.0;
end
Here my ra is any array of elements like and the condition should satisfy each element of an array.
So how should i write it

Guillaume on 26 Sep 2014
Edited: Guillaume on 26 Sep 2014
Use all (or any if you just want some elements to statisfy the condition)
if all(ra >= 1.12246*sigma)
%...
end
Note, this assume ra is a vector and sigma is scalar. If ra is a matrix:
if all(ra(:) >= 1.12246*sigma)
%...
end
Uday padidela on 28 Sep 2014
I have given the details of my code in the thread If condition is not working
My ra values are from 0 to 8.7345 with interval of 0.1066.
And my sigma have 3 values 32, 16.15 and 0.3.
I have used this condition in my potential.
My potential should decay and die off to zero on long run of my ra, but its not so.
Thank you

Stephen23 on 26 Sep 2014
Edited: Stephen23 on 26 Sep 2014
Actually you don't need to do anything. In MATLAB, the if function already is defined to be satisfied IFF every element of the conditional array is non-zero.
The documentation states this clearly "An evaluated expression is true when the result is nonempty and contains all nonzero elements (logical or real numeric). Otherwise, the expression is false."
So you example will calculate the code within the if, only if all of (ra >= 1.12246*sigma) are true.
If you only need some of them to be true, then you will need to use an any.
Uday padidela on 28 Sep 2014
But the condition is working.

David Young on 28 Sep 2014
You should try to state more clearly what is not working. Give an example set of initial values, say what you expect the result to be, and say what result you actually get. Without this, it's really hard to help you.
All the same, here's a guess. Maybe you need:
uw(ra >= 1.12246*sigma) = 0.0;
This applies the test to each element of ra and sets the corresponding element of uw to zero if the element of ra passes the test.