<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Sat, Apr 2, 2016 at 7:15 AM, Rongliang Chen <span dir="ltr"><<a href="mailto:rl.chen@siat.ac.cn" target="_blank">rl.chen@siat.ac.cn</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
  <div bgcolor="#FFFFFF" text="#000000">
    <div>Hi Matt,<br>
      <br>
      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? <br></div></div></blockquote><div><br></div><div>Exactly that you get this error message, and it should be in the documentation.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000"><div>
      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. <br></div></div></blockquote><div><br></div><div>Then we need to put that check in the explicit method as well. You should never be changing the input guess.</div><div><br></div><div>  Thanks,</div><div><br></div><div>    Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000"><div>
      Best regards,<br>
      Rongliang<br>
      <br>
      <pre cols="72"></pre>
      On 04/02/2016 07:59 PM, Matthew Knepley wrote:<br>
    </div>
    <blockquote type="cite">
      <div dir="ltr">
        <div class="gmail_extra">
          <div class="gmail_quote">On Sat, Apr 2, 2016 at 6:49 AM,
            Rongliang Chen <span dir="ltr"><<a href="mailto:rl.chen@siat.ac.cn" target="_blank">rl.chen@siat.ac.cn</a>></span> wrote:<br>
            <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
              <div bgcolor="#FFFFFF" text="#000000">
                <div>Hi Dave,<br>
                  <br>
                  I did not call any VecGetArrary and VecGetArraryRead
                  in function FormMassTimeStepFunction().<br>
                </div>
              </div>
            </blockquote>
            <div><br>
            </div>
            <div>It looks like you have a function FormMassTimeStep()
              inside your FormFunction() method. This</div>
            <div>has an argument X, the solution guess, which is
              read-only. However, you are calling DMLocalToGlobal()</div>
            <div>using that X, which is illegal, since its read-only. Is
              this right?</div>
            <div><br>
            </div>
            <div>   Matt</div>
            <div> </div>
            <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
              <div bgcolor="#FFFFFF" text="#000000">
                <div> Best regards,<br>
                  Rongliang<br>
                  <br>
                  On 04/02/2016 06:20 PM, Dave May wrote:<br>
                </div>
                <blockquote type="cite">
                  <div dir="ltr"><br>
                    <div class="gmail_extra"><br>
                      <div class="gmail_quote">On 2 April 2016 at 11:18,
                        Rongliang Chen <span dir="ltr"><<a href="mailto:rl.chen@siat.ac.cn" target="_blank">rl.chen@siat.ac.cn</a>></span>
                        wrote:<br>
                        <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi Shri,<br>
                          <br>
                          Thanks for your reply.<br>
                          <br>
                          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()?<br>
                        </blockquote>
                        <div><br>
                        </div>
                        <div>No - you should change it in your function
                          FormMassTimeStepFunction().<br>
                        </div>
                        <div>The input vector x passed into
                          SNESComputeFunction() is read only.<br>
                        </div>
                        <div> <br>
                          <br>
                        </div>
                        <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> <br>
                          I tried it and I got a warning when I make the
                          petsc:<br>
                          <br>
                          /home/rlchen/soft/petsc-3.6.3/src/dm/interface/dm.c:
                          In function ‘DMLocalToGlobalBegin’:<br>
                          /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]<br>
                          In file included from
                          /home/rlchen/soft/petsc-3.6.3/include/petscmat.h:6:0,<br>
                          from
                          /home/rlchen/soft/petsc-3.6.3/include/petscdm.h:6,<br>
                          from
                          /home/rlchen/soft/petsc-3.6.3/include/petsc/private/dmimpl.h:6,<br>
                          from
                          /home/rlchen/soft/petsc-3.6.3/src/dm/interface/dm.c:1:<br>
                          /home/rlchen/soft/petsc-3.6.3/include/petscvec.h:420:29:

                          note: expected ‘const PetscScalar **’ but
                          argument is of type ‘PetscScalar **’<br>
                          <br>
                          Best regards,<br>
                          Rongliang<br>
                          <br>
                          ---------------------<br>
                          Rongliang Chen,   PhD<br>
                          Associate Professor<br>
                          <br>
                          Laboratory for Engineering and Scientific
                          Computing<br>
                          Shenzhen Institutes of Advanced Technology<br>
                          Chinese Academy of Sciences<br>
                          Address: 1068 Xueyuan Avenue, Shenzhen
                          University Town, Shenzhen, Guangdong (518055),
                          P. R. China<br>
                          E-mail:  <a href="mailto:rl.chen@siat.ac.cn" target="_blank">rl.chen@siat.ac.cn</a><br>
                          Phone: <a href="tel:%2B86-755-86392312" value="+8675586392312" target="_blank">+86-755-86392312</a>
                          <div>
                            <div><br>
                              <br>
                              On 04/02/2016 05:03 PM, Abhyankar,
                              Shrirang G. wrote:<br>
                              <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> Use
                                VecGetArrayRead instead of VecGetArray<br>
                                <br>
                                <a href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Vec/VecGetArray" rel="noreferrer" target="_blank">http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Vec/VecGetArray</a><br>
                                Read.html<br>
                                <br>
                                <br>
                                Shri<br>
                                <br>
                                -----Original Message-----<br>
                                From: Rongliang Chen <<a href="mailto:rl.chen@siat.ac.cn" target="_blank">rl.chen@siat.ac.cn</a>><br>
                                Date: Saturday, April 2, 2016 at 3:51 AM<br>
                                To: PETSc users list <<a href="mailto:petsc-users@mcs.anl.gov" target="_blank">petsc-users@mcs.anl.gov</a>>,
                                "<a href="mailto:rongliang.chan@gmail.com" target="_blank">rongliang.chan@gmail.com</a>"<br>
                                <<a href="mailto:rongliang.chan@gmail.com" target="_blank">rongliang.chan@gmail.com</a>><br>
                                Subject: [petsc-users] Vec is locked
                                read only<br>
                                <br>
                                <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
                                  Dear All,<br>
                                  <br>
                                  My code got the following error
                                  messages, but the code works well for<br>
                                  the petsc optimized version
                                  (--with-debugging=0). Anyone can tell
                                  me how<br>
                                  to fix this problem?<br>
                                  <br>
                                  Best regards,<br>
                                  Rongliang<br>
                                  <br>
                                  <br>
                                  [0]PETSC ERROR: ---------------------
                                  Error Message<br>
--------------------------------------------------------------<br>
                                  [0]PETSC ERROR: Object is in wrong
                                  state<br>
                                  [0]PETSC ERROR:  Vec is locked read
                                  only, argument # 1<br>
                                  [0]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html" rel="noreferrer" target="_blank">http://www.mcs.anl.gov/petsc/documentation/faq.html</a><br>
                                  for trouble shooting.<br>
                                  [0]PETSC ERROR: Petsc Release Version
                                  3.6.3, Dec, 03, 2015<br>
                                  [0]PETSC ERROR: ./Nwtun on a
                                  64bit-debug named rlchen by rlchen Sat
                                  Apr<br>
                                  2 15:40:32 2016<br>
                                  [0]PETSC ERROR: Configure options
                                  --download-blacs --download-scalapack<br>
                                  --download-metis --download-parmetis
                                  --download-exodusii<br>
                                  --download-netcdf --download-hdf5<br>
--with-mpi-dir=/home/rlchen/soft/Program/mpich2-shared<br>
                                  --with-debugging=1
                                  --download-fblaslapack
                                  --download-chaco<br>
                                  [0]PETSC ERROR: #1 VecGetArray() line
                                  1646 in<br>
/home/rlchen/soft/petsc-3.6.3/src/vec/vec/interface/rvector.c<br>
                                  [0]PETSC ERROR: #2
                                  DMLocalToGlobalBegin() line 1913 in<br>
/home/rlchen/soft/petsc-3.6.3/src/dm/interface/dm.c<br>
                                  [0]PETSC ERROR: #3
                                  FormMassTimeStepFunction() line 191 in<br>
/home/rlchen/soft/3D_fluid/FiniteVolumeMethod/PETScCodes/codefor3.6/SetupF<br>
                                  unctions.c<br>
                                  [0]PETSC ERROR: #4 FormFunction() line
                                  46 in<br>
/home/rlchen/soft/3D_fluid/FiniteVolumeMethod/PETScCodes/codefor3.6/SetupF<br>
                                  unctions.c<br>
                                  [0]PETSC ERROR: #5
                                  SNESComputeFunction() line 2067 in<br>
/home/rlchen/soft/petsc-3.6.3/src/snes/interface/snes.c<br>
                                  [0]PETSC ERROR: #6
                                  SNESSolve_NEWTONLS() line 184 in<br>
/home/rlchen/soft/petsc-3.6.3/src/snes/impls/ls/ls.c<br>
                                  [0]PETSC ERROR: #7 SNESSolve() line
                                  3906 in<br>
/home/rlchen/soft/petsc-3.6.3/src/snes/interface/snes.c<br>
                                  [0]PETSC ERROR: #8
                                  SolveTimeDependent() line 843 in<br>
/home/rlchen/soft/3D_fluid/FiniteVolumeMethod/PETScCodes/codefor3.6/Nwtun.<br>
                                  c<br>
                                  [0]PETSC ERROR: #9 main() line 452 in<br>
/home/rlchen/soft/3D_fluid/FiniteVolumeMethod/PETScCodes/codefor3.6/Nwtun.<br>
                                  c<br>
                                  <br>
                                  <br>
                                </blockquote>
                                <br>
                              </blockquote>
                              <br>
                              <br>
                            </div>
                          </div>
                        </blockquote>
                      </div>
                      <br>
                    </div>
                  </div>
                </blockquote>
                <br>
              </div>
            </blockquote>
          </div>
          <br>
          <br clear="all"><span class="HOEnZb"><font color="#888888">
          <div><br>
          </div>
          -- <br>
          <div>What most experimenters take for
            granted before they begin their experiments is infinitely
            more interesting than any results to which their experiments
            lead.<br>
            -- Norbert Wiener</div>
        </font></span></div>
      </div>
    </blockquote>
    <br>
  </div>

</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature">What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener</div>
</div></div>