Removing double values from matrices

I have two matrices, X and Y, which are essentially a set of coordinates. The problem is that some values in matrix Y have more than one value associated in the X matrix and these doubles appear without any order. Both matrices are approximately 5000 in length. I would like to add all the duplicate X values associated with one Y value together. Is there any way to do this?

Answer 1

[John D'Errico]

You can find consolidator on the file exchange. It is designed to do exactly that.

[jgillis16]

The problem is that it seems consolidator only removes the duplicates, and doesn't have the option to add them together.