Hi, I'll start out by saying I'm a new user to PETSc. I'm actually using SLEPc which is a package for eigenvalue problems and is built on top of PETSc and I have a question about the MatTranspose function.
I have a very large, very sparse matrix with dimensions on the order of 3 million by 1 million. I created my matrix using MatCreateMPIAIJ and it seems to be evenly distributed across my machines. I've hit a bottleneck when running some code to compute the SVD of the matrix and the bottleneck seems to be using the MatTranspose operation on my matrix. This operation runs for a very long time. I ran a job over the weekend and it still seems to be in this function. (Running for on the order of 60 hours at this point.) It also seems to only being using one of the processors available to it. When MatTranspose runs does it go through every element and then send messages between the process? Or for sparse matrices does it only reorder the elements that are not zero? Or is there something else going on that explains this behavior? Thanks, Sarah Osentoski
