1*c4762a1bSJed Brown ---------- Testing Jacobian ------------- 2*c4762a1bSJed Brown Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference 3*c4762a1bSJed Brown of hand-coded and finite difference Jacobian entries greater than <threshold>. 4*c4762a1bSJed Brown Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is 5*c4762a1bSJed Brown O(1.e-8), the hand-coded Jacobian is probably correct. 6*c4762a1bSJed Brown ||J - Jfd||_F/||J||_F = 1.98363e-12, ||J - Jfd||_F = 7.88431e-09 7