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I have a FEA problem that I am trying to solve with GAMG. The
problem solves<br>
just fine with direct solvers (mumps, superlu) and iterative solvers
(gmres, ml, hypre-boomer) etc.<br>
<br>
However with GAMG I am getting a divide by zero that I am having
trouble tracking down. Below<br>
is the gdb stack trace and the source lines going up the stack. <br>
<br>
When I run in valgrind the problem runs fine (and gets the correct
answer).<br>
Valgrind reports nothing of note (just lots of indirectly lost
blocks related to PMP_INIT).<br>
<br>
I'm only running on one processor.<br>
<br>
Any suggestions on where to start to trace the problem?<br>
<br>
-sanjay<br>
<br>
<blockquote>#0 0x00007fb262dc5be1 in ieeeck_ () from
/lib64/liblapack.so.3<br>
#1 0x00007fb262dc5332 in ilaenv_ () from /lib64/liblapack.so.3<br>
#2 0x00007fb262dbbcef in dlasq2_ () from /lib64/liblapack.so.3<br>
#3 0x00007fb262dbb78c in dlasq1_ () from /lib64/liblapack.so.3<br>
#4 0x00007fb262da1e2e in dbdsqr_ () from /lib64/liblapack.so.3<br>
#5 0x00007fb262960110 in dgesvd_ () from /lib64/liblapack.so.3<br>
#6 0x00007fb264e74b66 in KSPComputeExtremeSingularValues_GMRES
(ksp=0x1816560, emax=0x7ffc5010e7c8, emin=0x7ffc5010e7d0) at
/home/sg/petsc-3.13.2/src/ksp/ksp/impls/gmres/gmreig.c:32<br>
#7 0x00007fb264dfe69a in KSPComputeExtremeSingularValues
(ksp=0x1816560, emax=0x7ffc5010e7c8, emin=0x7ffc5010e7d0) at
/home/sg/petsc-3.13.2/src/ksp/ksp/interface/itfunc.c:64<br>
#8 0x00007fb264b44a1f in PCGAMGOptProlongator_AGG (pc=0x12f3d30,
Amat=0x11a2630, a_P=0x7ffc5010ebe0) at
/home/sg/petsc-3.13.2/src/ksp/pc/impls/gamg/agg.c:1145<br>
#9 0x00007fb264b248a1 in PCSetUp_GAMG (pc=0x12f3d30) at
/home/sg/petsc-3.13.2/src/ksp/pc/impls/gamg/gamg.c:557<br>
#10 0x00007fb264d8535b in PCSetUp (pc=0x12f3d30) at
/home/sg/petsc-3.13.2/src/ksp/pc/interface/precon.c:898<br>
#11 0x00007fb264e01a93 in KSPSetUp (ksp=0x128dd80) at
/home/sg/petsc-3.13.2/src/ksp/ksp/interface/itfunc.c:376<br>
#12 0x00007fb264e057af in KSPSolve_Private (ksp=0x128dd80,
b=0x1259f30, x=0x125d910) at
/home/sg/petsc-3.13.2/src/ksp/ksp/interface/itfunc.c:633<br>
#13 0x00007fb264e086b9 in KSPSolve (ksp=0x128dd80, b=0x1259f30,
x=0x125d910) at
/home/sg/petsc-3.13.2/src/ksp/ksp/interface/itfunc.c:853<br>
#14 0x00007fb264e46216 in kspsolve_ (ksp=0x832670
<__pfeapc_MOD_kspsol>, b=0x832698 <__pfeapc_MOD_rhs>,
x=0x8326a0 <__pfeapc_MOD_sol>, __ierr=0x7ffc5010f358)<br>
at
/home/sg/petsc-3.13.2/src/ksp/ksp/interface/ftn-auto/itfuncf.c:266<br>
#15 0x000000000043298d in usolve (flags=..., b=...) at
usolve.F:313<br>
#16 0x000000000044afba in psolve (stype=-3, b=..., fp=...,
factor=.TRUE., solve=.TRUE., cfr=.FALSE., prnt=.TRUE.) at
psolve.f:212<br>
#17 0x00000000006b7393 in pmacr1 (lct=..., ct=..., j=3,
_lct=_lct@entry=15) at pmacr1.f:578<br>
#18 0x00000000005c247b in pmacr (initf=.FALSE.) at pmacr.f:578<br>
#19 0x000000000044ff20 in pcontr () at pcontr.f:1307<br>
#20 0x0000000000404d9b in feap () at feap86.f:162<br>
#21 main (argc=<optimized out>, argv=<optimized out>)
at feap86.f:168<br>
#22 0x00007fb261aaef43 in __libc_start_main () from
/lib64/libc.so.6<br>
#23 0x0000000000404dde in _start ()<br>
<br>
(gdb) list<br>
1 <built-in>: No such file or directory.<br>
(gdb) up<br>
#1 0x00007fb262dc5332 in ilaenv_ () from /lib64/liblapack.so.3<br>
(gdb) up<br>
#2 0x00007fb262dbbcef in dlasq2_ () from /lib64/liblapack.so.3<br>
(gdb) up<br>
#3 0x00007fb262dbb78c in dlasq1_ () from /lib64/liblapack.so.3<br>
(gdb) up<br>
#4 0x00007fb262da1e2e in dbdsqr_ () from /lib64/liblapack.so.3<br>
(gdb) up<br>
#5 0x00007fb262960110 in dgesvd_ () from /lib64/liblapack.so.3<br>
(gdb) up<br>
#6 0x00007fb264e74b66 in KSPComputeExtremeSingularValues_GMRES
(ksp=0x1816560, emax=0x7ffc5010e7c8, emin=0x7ffc5010e7d0) at
/home/sg/petsc-3.13.2/src/ksp/ksp/impls/gmres/gmreig.c:32<br>
32
PetscStackCallBLAS("LAPACKgesvd",LAPACKgesvd_("N","N",&bn,&bn,R,&bN,realpart,&sdummy,&idummy,&sdummy,&idummy,work,&lwork,&lierr));<br>
(gdb) up<br>
#7 0x00007fb264dfe69a in KSPComputeExtremeSingularValues
(ksp=0x1816560, emax=0x7ffc5010e7c8, emin=0x7ffc5010e7d0) at
/home/sg/petsc-3.13.2/src/ksp/ksp/interface/itfunc.c:64<br>
64 ierr =
(*ksp->ops->computeextremesingularvalues)(ksp,emax,emin);CHKERRQ(ierr);<br>
(gdb) up<br>
#8 0x00007fb264b44a1f in PCGAMGOptProlongator_AGG (pc=0x12f3d30,
Amat=0x11a2630, a_P=0x7ffc5010ebe0) at
/home/sg/petsc-3.13.2/src/ksp/pc/impls/gamg/agg.c:1145<br>
1145 ierr = KSPComputeExtremeSingularValues(eksp,
&emax, &emin);CHKERRQ(ierr);<br>
(gdb) up<br>
#9 0x00007fb264b248a1 in PCSetUp_GAMG (pc=0x12f3d30) at
/home/sg/petsc-3.13.2/src/ksp/pc/impls/gamg/gamg.c:557<br>
557 ierr = pc_gamg->ops->optprolongator(pc,
Aarr[level], &Prol11);CHKERRQ(ierr);<br>
(gdb) up<br>
#10 0x00007fb264d8535b in PCSetUp (pc=0x12f3d30) at
/home/sg/petsc-3.13.2/src/ksp/pc/interface/precon.c:898<br>
898 ierr = (*pc->ops->setup)(pc);CHKERRQ(ierr);<br>
(gdb) up<br>
#11 0x00007fb264e01a93 in KSPSetUp (ksp=0x128dd80) at
/home/sg/petsc-3.13.2/src/ksp/ksp/interface/itfunc.c:376<br>
376 ierr = PCSetUp(ksp->pc);CHKERRQ(ierr);<br>
(gdb) up<br>
#12 0x00007fb264e057af in KSPSolve_Private (ksp=0x128dd80,
b=0x1259f30, x=0x125d910) at
/home/sg/petsc-3.13.2/src/ksp/ksp/interface/itfunc.c:633<br>
633 ierr = KSPSetUp(ksp);CHKERRQ(ierr);<br>
(gdb) up<br>
#13 0x00007fb264e086b9 in KSPSolve (ksp=0x128dd80, b=0x1259f30,
x=0x125d910) at
/home/sg/petsc-3.13.2/src/ksp/ksp/interface/itfunc.c:853<br>
853 ierr = KSPSolve_Private(ksp,b,x);CHKERRQ(ierr);<br>
(gdb) up<br>
#14 0x00007fb264e46216 in kspsolve_ (ksp=0x832670
<__pfeapc_MOD_kspsol>, b=0x832698 <__pfeapc_MOD_rhs>,
x=0x8326a0 <__pfeapc_MOD_sol>, __ierr=0x7ffc5010f358)<br>
at
/home/sg/petsc-3.13.2/src/ksp/ksp/interface/ftn-auto/itfuncf.c:266<br>
266 *__ierr = KSPSolve(<br>
(gdb) up<br>
#15 0x000000000043298d in usolve (flags=..., b=...) at
usolve.F:313<br>
313 call KSPSolve (kspsol, rhs, sol, ierr)<br>
</blockquote>
<br>
<br>
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