MATLAB: using the find function to get indices of a certain value in an array

Question

I have made an array of doubles and when I want to use the find command to search for the indices of specific values in the array, this yields an empty matrix which is not w

Answer 1

Testing for equality with floating-point numbers is almost always a bad idea. What you probably want to do is test to see which numbers are close enough to the target value:

peaks = find( abs( y - .8236 ) < .0001 );