On Wed, 21 Jul 2010 12:27:41 -0400, Verena Kuhlemann <vkuhlem at emory.edu> wrote: > Is there a Mat function that computes A+A^T? > I couldn't find one, but maybe I missed it. /* B = A + A^T */ MatTranspose(A,MAT_INITIAL_MATRIX,&B); MatAXPY(B,1.0,A,DIFFERENT_NONZERO_PATTERN); You can use SAME_NONZERO_PATTERN if the matrix is structurally symmetric. Jed