---- Minimum Surface Area Problem ----- mx: 10 my: 10 iter = 0, Function value 1.46076, Residual: 0.207785 iter = 0, Function value 1.43581, Residual: 0.187715 iter = 1, Function value 1.41867, Residual: 0.0159523 iter = 2, Function value 1.41847, Residual: 0.000148677 iter = 3, Function value 1.41847, Residual: < 1.0e-6 Tao Object: 2 MPI processes type: nls Newton steps: 3 BFGS steps: 0 Gradient steps: 0 TaoLineSearch Object: 2 MPI processes type: more-thuente maximum function evaluations=30 tolerances: ftol=0.0001, rtol=1e-10, gtol=0.9 total number of function evaluations=0 total number of gradient evaluations=0 total number of function/gradient evaluations=1 Termination reason: SUCCESS KSP Object: (tao_nls_) 2 MPI processes type: stcg maximum iterations=15, initial guess is zero tolerances: relative=1e-05, absolute=1e-50, divergence=10000. left preconditioning using UNPRECONDITIONED norm type for convergence test PC Object: (tao_nls_) 2 MPI processes type: bjacobi number of blocks = 2 Local solver information for first block is in the following KSP and PC objects on rank 0: Use -tao_nls_ksp_view ::ascii_info_detail to display information for all blocks KSP Object: (tao_nls_sub_) 1 MPI process type: preonly maximum iterations=10000, initial guess is zero tolerances: relative=1e-05, absolute=1e-50, divergence=10000. left preconditioning not checking for convergence PC Object: (tao_nls_sub_) 1 MPI process type: ilu out-of-place factorization 0 levels of fill tolerance for zero pivot 2.22045e-14 matrix ordering: natural factor fill ratio given 1., needed 1. Factored matrix: Mat Object: (tao_nls_sub_) 1 MPI process type: seqaij rows=50, cols=50 package used to perform factorization: petsc total: nonzeros=364, allocated nonzeros=364 not using I-node routines linear system matrix, which is also used to construct the preconditioner: Mat Object: (tao_nls_sub_) 1 MPI process type: seqaij rows=50, cols=50 total: nonzeros=364, allocated nonzeros=364 total number of mallocs used during MatSetValues calls=0 not using I-node routines linear system matrix, which is also used to construct the preconditioner: Mat Object: 2 MPI processes type: mpiaij rows=100, cols=100 total: nonzeros=784, allocated nonzeros=784 total number of mallocs used during MatSetValues calls=0 total KSP iterations: 36 convergence tolerances: gatol=0.0001, grtol=1e-05, steptol=0., gttol=0. Residual in Function/Gradient:=2.64235e-08 Objective value=1.41847 total number of iterations=3, (max: 50) total number of function evaluations=5, (max: unlimited) total number of function/gradient evaluations=5, (max: unlimited) total number of Hessian evaluations=4 Solution converged: ||g(X)|| <= gatol