Hello, I am trying to solve a linear system of vibroacoustic Problem with 12328 dimension.
When I use bcgs and ilu(1) with n=1 proc, I get: ---Norm of residual=4.58868e+17 ---Norm of error(u-x)=75.0051 ---Number of iteration=7 ---Solution Time=3.896039 second When I use bcgs and ilu(2) with n=1 proc, I get a different error message: ---[0]PETSC ERROR: MatLUFactorNumeric_SeqAIJ() line 537 in src/mat/impls/aij/seq/aijfact.c [0]PETSC ERROR: Detected zero pivot in LU factorization! [0]PETSC ERROR: Zero pivot row 10816 value 5.0874e+06 tolerance 1e-12 * rs 7.29416e+20! [0]PETSC ERROR: MatLUFactorNumeric() line 1831 in src/mat/interface/matrix.c .................... That system seems to converge immediately, at first, with 7 iters. But the norm of residual is increadibly high. Did you face with that situation? Can that be the result of divergence? Best Regards, Buket Benek
