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

[Song Gao]

Thank you. That's cool. Sorry, I'm not good at gdb.

I did that. They are the same. One gave
(gdb) p *alpha
$1 = 0.013169008988739605

and another gave
(gdb) p *alpha
$1 = 0.013169008988739673

2015-03-11 17:35 GMT-04:00 Matthew Knepley <knepley at gmail.com>:

> On Wed, Mar 11, 2015 at 3:39 PM, Song Gao <song.gao2 at mail.mcgill.ca>
> wrote:
>
>> Thanks.
>>
>> I run with two processes. When the code stop, I'm in      raise()     and
>> alpha is not in the current context.
>>
>
> Here you would use:
>
>   (gdb) up 4
>
>   (gdb) p *alpha
>
>    Matt
>
>
>> (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
>>>
>>
>>
>
>
> --
> 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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