[petsc-users] MatMult doesn't give the correct result

Dear all, I tried to use MatMult on a 2*2 matrix but could not get the right answer. With MatView I saw the Matrix was correctly defined as : row 0: (0, 0.707107) row 1: (1, 0.707107) The vector to be multiplied is 0 -0.0141421 But MatMult gave the result vector as 0 -0.01 Has anyone a clue to the problem? Thank you for you help in advance. Cheers, Longmin