[petsc-users] Vec is locked read only

Sat Apr 2 07:19:35 CDT 2016

On Sat, Apr 2, 2016 at 7:15 AM, Rongliang Chen <rl.chen at siat.ac.cn> wrote:

> Hi Matt,
>
> That's right. The FormMassTimeStep() is inside the FormFunction() and I
> call the FormFunction() in this way: SNESSetFunction(user->snes,
> algebra->f, FormFunction, (void*)user). How can I know the X is read-only
> or not?
>

Exactly that you get this error message, and it should be in the
documentation.

> If I do not use the SNESSolve, that is I use the explicit method with the
> same function FormMassTimeStep(), this error disappeared. So it seems that
> the SNESSolve locked the vector X.
>

Then we need to put that check in the explicit method as well. You should
never be changing the input guess.

  Thanks,

    Matt

> Best regards,
> Rongliang
>
> On 04/02/2016 07:59 PM, Matthew Knepley wrote:
>
> On Sat, Apr 2, 2016 at 6:49 AM, Rongliang Chen <rl.chen at siat.ac.cn> wrote:
>
>> Hi Dave,
>>
>> I did not call any VecGetArrary and VecGetArraryRead in function
>> FormMassTimeStepFunction().
>>
>
> It looks like you have a function FormMassTimeStep() inside your
> FormFunction() method. This
> has an argument X, the solution guess, which is read-only. However, you
> are calling DMLocalToGlobal()
> using that X, which is illegal, since its read-only. Is this right?
>
>    Matt
>
>
>> Best regards,
>> Rongliang
>>
>> On 04/02/2016 06:20 PM, Dave May wrote:
>>
>>
>>
>> On 2 April 2016 at 11:18, Rongliang Chen <rl.chen at siat.ac.cn> wrote:
>>
>>> Hi Shri,
>>>
>>> Thanks for your reply.
>>>
>>> Do you mean that I need to change the VecGetArrary() in
>>> /home/rlchen/soft/petsc-3.6.3/src/dm/interface/dm.c to VecGetArrayRead()?
>>>
>>
>> No - you should change it in your function FormMassTimeStepFunction().
>> The input vector x passed into SNESComputeFunction() is read only.
>>
>>
>>
>>> I tried it and I got a warning when I make the petsc:
>>>
>>> /home/rlchen/soft/petsc-3.6.3/src/dm/interface/dm.c: In function
>>> ‘DMLocalToGlobalBegin’:
>>> /home/rlchen/soft/petsc-3.6.3/src/dm/interface/dm.c:1913:5: warning:
>>> passing argument 2 of ‘VecGetArrayRead’ from incompatible pointer type
>>> [enabled by default]
>>> In file included from
>>> /home/rlchen/soft/petsc-3.6.3/include/petscmat.h:6:0,
>>> from /home/rlchen/soft/petsc-3.6.3/include/petscdm.h:6,
>>> from /home/rlchen/soft/petsc-3.6.3/include/petsc/private/dmimpl.h:6,
>>> from /home/rlchen/soft/petsc-3.6.3/src/dm/interface/dm.c:1:
>>> /home/rlchen/soft/petsc-3.6.3/include/petscvec.h:420:29: note: expected
>>> ‘const PetscScalar **’ but argument is of type ‘PetscScalar **’
>>>
>>> Best regards,
>>> Rongliang
>>>
>>> ---------------------
>>> Rongliang Chen,   PhD
>>> Associate Professor
>>>
>>> Laboratory for Engineering and Scientific Computing
>>> Shenzhen Institutes of Advanced Technology
>>> Chinese Academy of Sciences
>>> Address: 1068 Xueyuan Avenue, Shenzhen University Town, Shenzhen,
>>> Guangdong (518055), P. R. China
>>> E-mail:  rl.chen at siat.ac.cn
>>> Phone: +86-755-86392312
>>>
>>>
>>> On 04/02/2016 05:03 PM, Abhyankar, Shrirang G. wrote:
>>>
>>>> Use VecGetArrayRead instead of VecGetArray
>>>>
>>>>
>>>> http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Vec/VecGetArray
>>>> Read.html
>>>>
>>>>
>>>> Shri
>>>>
>>>> -----Original Message-----
>>>> From: Rongliang Chen <rl.chen at siat.ac.cn>
>>>> Date: Saturday, April 2, 2016 at 3:51 AM
>>>> To: PETSc users list <petsc-users at mcs.anl.gov>, "
>>>> rongliang.chan at gmail.com"
>>>> <rongliang.chan at gmail.com>
>>>> Subject: [petsc-users] Vec is locked read only
>>>>
>>>> Dear All,
>>>>>
>>>>> My code got the following error messages, but the code works well for
>>>>> the petsc optimized version (--with-debugging=0). Anyone can tell me
>>>>> how
>>>>> to fix this problem?
>>>>>
>>>>> Best regards,
>>>>> Rongliang
>>>>>
>>>>>
>>>>> [0]PETSC ERROR: --------------------- Error Message
>>>>> --------------------------------------------------------------
>>>>> [0]PETSC ERROR: Object is in wrong state
>>>>> [0]PETSC ERROR:  Vec is locked read only, argument # 1
>>>>> [0]PETSC ERROR: See
>>>>> http://www.mcs.anl.gov/petsc/documentation/faq.html
>>>>> for trouble shooting.
>>>>> [0]PETSC ERROR: Petsc Release Version 3.6.3, Dec, 03, 2015
>>>>> [0]PETSC ERROR: ./Nwtun on a 64bit-debug named rlchen by rlchen Sat Apr
>>>>> 2 15:40:32 2016
>>>>> [0]PETSC ERROR: Configure options --download-blacs --download-scalapack
>>>>> --download-metis --download-parmetis --download-exodusii
>>>>> --download-netcdf --download-hdf5
>>>>> --with-mpi-dir=/home/rlchen/soft/Program/mpich2-shared
>>>>> --with-debugging=1 --download-fblaslapack --download-chaco
>>>>> [0]PETSC ERROR: #1 VecGetArray() line 1646 in
>>>>> /home/rlchen/soft/petsc-3.6.3/src/vec/vec/interface/rvector.c
>>>>> [0]PETSC ERROR: #2 DMLocalToGlobalBegin() line 1913 in
>>>>> /home/rlchen/soft/petsc-3.6.3/src/dm/interface/dm.c
>>>>> [0]PETSC ERROR: #3 FormMassTimeStepFunction() line 191 in
>>>>>
>>>>> /home/rlchen/soft/3D_fluid/FiniteVolumeMethod/PETScCodes/codefor3.6/SetupF
>>>>> unctions.c
>>>>> [0]PETSC ERROR: #4 FormFunction() line 46 in
>>>>>
>>>>> /home/rlchen/soft/3D_fluid/FiniteVolumeMethod/PETScCodes/codefor3.6/SetupF
>>>>> unctions.c
>>>>> [0]PETSC ERROR: #5 SNESComputeFunction() line 2067 in
>>>>> /home/rlchen/soft/petsc-3.6.3/src/snes/interface/snes.c
>>>>> [0]PETSC ERROR: #6 SNESSolve_NEWTONLS() line 184 in
>>>>> /home/rlchen/soft/petsc-3.6.3/src/snes/impls/ls/ls.c
>>>>> [0]PETSC ERROR: #7 SNESSolve() line 3906 in
>>>>> /home/rlchen/soft/petsc-3.6.3/src/snes/interface/snes.c
>>>>> [0]PETSC ERROR: #8 SolveTimeDependent() line 843 in
>>>>>
>>>>> /home/rlchen/soft/3D_fluid/FiniteVolumeMethod/PETScCodes/codefor3.6/Nwtun.
>>>>> c
>>>>> [0]PETSC ERROR: #9 main() line 452 in
>>>>>
>>>>> /home/rlchen/soft/3D_fluid/FiniteVolumeMethod/PETScCodes/codefor3.6/Nwtun.
>>>>> 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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