Problem: I have an m-by-n matrix of values, some positive and some negative, and I am only concerned with values greater than zero. I used logical operators to set all values in the original array that are less than zero to zero, and would like to then be able to do some operation on only those column values that are greater than zero, for instance, find the IRR of the column for all values >0.
I have found the row subscripts (and linear indices) for the first element and last non-zero element in each of the columns, but can't figure out how to use these to calculate the IRR/SUM/other operation on each column individually.
Attached is the variable I am referencing. I am trying to apply a function (IRR) to only positive rows and return the IRR for the positive elements in each column (so rows 1:317 for column 1).
Thanks in advance for your help!
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