Hello,
I have used the GMRES solver in PETSc successfully up to now, but on
installing the most recent release, 3.20.3, the solver fails by exiting
early. Output from the code is:
lt-nbi-solve-laplace: starting PETSc solver [23.0537]
0 KSP Residual norm < 1.e-11
Linear solve converged due to CONVERGED_ATOL iterations 0
lt-nbi-solve-laplace: 0 iterations [23.0542] (22.9678)
and tracing execution shows the norm returned by VecNorm to be 0.
If I modify the function by commenting out line 217 of
src/vec/vec/interface/rvector.c
/* if (flg) PetscFunctionReturn(PETSC_SUCCESS); */
the code executes correctly:
lt-nbi-solve-laplace: starting PETSc solver [22.9392]
0 KSP Residual norm 1.10836
1 KSP Residual norm 0.0778301
2 KSP Residual norm 0.0125121
3 KSP Residual norm 0.00165836
4 KSP Residual norm 0.000164066
5 KSP Residual norm 2.12824e-05
6 KSP Residual norm 4.50696e-06
7 KSP Residual norm 5.85082e-07
Linear solve converged due to CONVERGED_RTOL iterations 7
My compile options are:
PETSC_ARCH=linux-gnu-real ./configure --with-mpi=0
--with-scalar-type=real --with-threadsafety --with-debugging=0
--with-log=0 --with-openmp
uname -a returns:
5.15.80 #1 SMP PREEMPT Sun Nov 27 13:28:05 CST 2022 x86_64 Intel(R)
Core(TM) i5-6200U CPU @ 2.30GHz GenuineIntel GNU/Linux
