search for: idmatrix

I have a matrix that I want to turn into a transformed matrix that includes the indices from the original matrix and the value. The matrix is simply real-valued and is square (and large (8k x 8k)). I want something that looks like (for the 3x3 case): i j value 1 1 1.0 1 2 0.783432 1 3 -0.123482 2 1 0.783432 2 2 1.0 2 3 0.928374 and so on.... I can do this with for loops, but there is