[petsc-users] The PETSC ERROR: VecMAXPY() when using GMRES

[Song Gao]

Thanks.

I run with two processes. When the code stop, I'm in      raise()     and
alpha is not in the current context.

(gdb)p alpha
No symbol "alpha" in current context.
(gdb)  bt
#0  0x0000003764432625 in raise () from /lib64/libc.so.6
#1  0x0000003764433e05 in abort () from /lib64/libc.so.6
#2  0x00000000015d02f5 in PetscAbortErrorHandler (comm=0x36e17a0,
line=1186,
    fun=0x279cad4 "VecMAXPY", file=0x279c404 "rvector.c",
    dir=0x279c1c8 "src/vec/vec/interface/", n=62, p=PETSC_ERROR_INITIAL,
    mess=0x7fff33ffa4c0 "Scalar value must be same on all processes,
argument # 3", ctx=0x0) at errabort.c:62
#3  0x000000000130cf44 in PetscError (comm=0x36e17a0, line=1186,
    func=0x279cad4 "VecMAXPY", file=0x279c404 "rvector.c",
    dir=0x279c1c8 "src/vec/vec/interface/", n=62, p=PETSC_ERROR_INITIAL,
    mess=0x279c720 "Scalar value must be same on all processes, argument #
%d")
    at err.c:356
#4  0x00000000013f8184 in VecMAXPY (y=0x3b35000, nv=20, alpha=0x3b31840,
    x=0x3b33080) at rvector.c:1186
#5  0x0000000001581062 in KSPGMRESBuildSoln (nrs=0x3b31840, vs=0x3ab2090,
    vdest=0x3ab2090, ksp=0x39a9700, it=19) at gmres.c:345


But I break at VecMAXPY. then print out alpha on both processes. For the
first few times that the breakpoint is hit , I checked the values on both
processes and they are the same.


(gdb) b VecMAXPY
Breakpoint 1 at 0x13f73e0: file rvector.c, line 1174.
(gdb) c
Continuing.
Breakpoint 1, VecMAXPY (y=0x3f2b790, nv=1, alpha=0x3f374e0, x=0x3f1fde0)
    at rvector.c:1174
1174      PetscFunctionBegin;
(gdb) p alpha
$1 = (const PetscScalar *) 0x3f374e0
(gdb) p *alpha
$2 = -0.54285016977140765
(gdb)

2015-03-11 15:52 GMT-04:00 Matthew Knepley <knepley at gmail.com>:

> On Wed, Mar 11, 2015 at 2:33 PM, Song Gao <song.gao2 at mail.mcgill.ca>
> wrote:
>
>> Hello,
>>
>> I'm solving Navier-Stokes equations by finite element method.  I use KSP
>> as the linear system solver. I run with 2 cpu. The code runs fine in
>> non-debug version. But when I switch to the debug version, the code gives
>> the following error.
>>
>> I output the matrix and rhs before calling KSPSolve to make sure no NAN
>> or INF in them. The condition number of matrix is ~2e4.  Seems okay.
>>
>> I also run the code with valgrind, but didn't find any other errors. The
>> valgrind output is attached. Any ideas of what I can do next?
>>
>
> Is there any chance you could spawn the debugger, -start_in_debugger, and
> when you get the error,
> print out the value of 'alpha' on each process?
>
> Otherwise the best thing to do is output your Mat and RHS in binary and
> send them so we can try to reproduce.
>
>     Matt
>
>   Thanks,
>
>      Matt
>
>
>> Thanks in advance.
>>
>>
>> [0]PETSC ERROR: --------------------- Error Message
>> ------------------------------------
>> [0]PETSC ERROR: Invalid argument!
>> [0]PETSC ERROR: Scalar value must be same on all processes, argument # 3!
>> [0]PETSC ERROR:
>> ------------------------------------------------------------------------
>> [0]PETSC ERROR: Petsc Release Version 3.3.0, Patch 7, Sat May 11 22:15:24
>> CDT 2013
>> [0]PETSC ERROR: See docs/changes/index.html for recent updates.
>> [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
>> [0]PETSC ERROR: See docs/index.html for manual pages.
>> [0]PETSC ERROR:
>> ------------------------------------------------------------------------
>> [0]PETSC ERROR:
>> /home/cfd/sgao/mycodes/fensap_new_edge_coefficient/fensapng-mf-newmuscl-overledg_org/bin/fensapMPI_LINUX64_DEBUG
>> on a linux named anakin by sgao Wed Mar 11 15:07:53 2015
>> [0]PETSC ERROR: Libraries linked from /tmp/PETSC33/petsc-3.3-p7/linux/lib
>> [0]PETSC ERROR: Configure run at Wed Jan 15 12:04:54 2014
>> [0]PETSC ERROR: Configure options
>> --with-mpi-dir=/usr/local.linux64/lib64/MPI-openmpi-1.4.5/
>> --with-shared-libraries=0 --COPTFLAGS=-g --FOPTFLAGS=-g --with-debugging=yes
>> [0]PETSC ERROR:
>> ------------------------------------------------------------------------
>> [0]PETSC ERROR: VecMAXPY() line 1186 in src/vec/vec/interface/rvector.c
>> [0]PETSC ERROR: KSPGMRESBuildSoln() line 345 in
>> src/ksp/ksp/impls/gmres/gmres.c
>> [0]PETSC ERROR: KSPGMRESCycle() line 206 in
>> src/ksp/ksp/impls/gmres/gmres.c
>> [0]PETSC ERROR: KSPSolve_GMRES() line 231 in
>> src/ksp/ksp/impls/gmres/gmres.c
>> [0]PETSC ERROR: KSPSolve() line 446 in src/ksp/ksp/interface/itfunc.c
>>
>>
>
>
> --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>
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