[petsc-users] Vec is locked read only

[Matthew Knepley]

On Sat, Apr 2, 2016 at 7:37 AM, Rongliang Chen <rl.chen at siat.ac.cn> wrote:

> Hi Matt,
>
> How to check in the explicit method? This kind of errors does come out in
> the explicit method.
>

You said "that is I use the explicit method with the same function
FormMassTimeStep(), this error disappeared"


> What do you mean "You should never be changing the input guess"? Do you
> mean that the value of the solution vector X in FormFunction are not
> allowed to be changed by the user defined function?
>

Yes.

   Matt


> Best regards,
> Rongliang
>
> On 04/02/2016 08:19 PM, Matthew Knepley wrote:
>
> 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
>
>
>


-- 
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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