<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Sat, Apr 2, 2016 at 8:18 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>On 04/02/2016 09:08 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 8:03 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>
                  Many thanks for your helps. I will change the way that
                  I used for the boundary condition setup.<br>
                </div>
              </div>
            </blockquote>
            <div><br>
            </div>
            <div>I will note that we (Barry, Jed, Mark, and I at least)
              have adopted the view that by and large</div>
            <div><br>
            </div>
            <div>  a) global vectors are for solvers</div>
            <div><br>
            </div>
            <div>  b) local vectors are for assembly</div>
            <div><br>
            </div>
            <div>For me, that means local vectors have ghost values and
              boundary conditions, but global vectors</div>
            <div>have them removed. This is how SNES ex12 and ex62 are
              organized.</div>
            <div><br>
            </div>
          </div>
        </div>
      </div>
    </blockquote>
    Does this means that if I want to use the local vector (obtained by
    DMGlobalToLocalBegin and DMGlobalToLocalEnd), I need to reset the
    boundary conditions for the local vector before I use it?<br></div></blockquote><div><br></div><div>Yes, that is how PETSc is setup internally.</div><div><br></div><div>  1) The solver generates a new initial guess</div><div><br></div><div>  2) PETSc calls DMGlobalToLocal(). In Plex, this adds in ghosts and BC</div><div><br></div><div>  3) The local guess is passed to FormFunctionLocal()</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">
    Best regards,<br>
    Rongliang<br>
    <br>
    <blockquote type="cite">
      <div dir="ltr">
        <div class="gmail_extra">
          <div class="gmail_quote">
            <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
                  <div>
                    <div><br>
                      <br>
                      <br>
                      On 04/02/2016 08:49 PM, Matthew Knepley wrote:<br>
                    </div>
                  </div>
                </div>
                <div>
                  <div>
                    <blockquote type="cite">
                      <div dir="ltr">
                        <div class="gmail_extra">
                          <div class="gmail_quote">On Sat, Apr 2, 2016
                            at 7:46 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>But I need to setup the boundary
                                  conditions for the solution vector X,
                                  which is in FormMassTimeStep(). <br>
                                </div>
                              </div>
                            </blockquote>
                            <div><br>
                            </div>
                            <div>Make a copy. The solution vector is
                              used in the solver, and you have no idea
                              exactly what it is doing with it.</div>
                            <div>Or put your boundary conditions in the
                              initial guess to SNESSolve().</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>
                                  <br>
                                  On 04/02/2016 08:37 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 7:37 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:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
                                          <div bgcolor="#FFFFFF" text="#000000">
                                            <div>Hi Matt,<br>
                                              <br>
                                              How to check in the
                                              explicit method? This kind
                                              of errors does come out in
                                              the explicit method. <br>
                                            </div>
                                          </div>
                                        </blockquote>
                                        <div><br>
                                        </div>
                                        <div>You said "that is I use the
                                          explicit method with the same
                                          function FormMassTimeStep(),
                                          this error disappeared"</div>
                                        <div> </div>
                                        <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
                                          <div bgcolor="#FFFFFF" text="#000000">
                                            <div> 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?<br>
                                            </div>
                                          </div>
                                        </blockquote>
                                        <div><br>
                                        </div>
                                        <div>Yes.</div>
                                        <div><br>
                                        </div>
                                        <div>   Matt</div>
                                        <div> </div>
                                        <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
                                          <div bgcolor="#FFFFFF" text="#000000">
                                            <div> Best regards,<br>
                                              Rongliang<br>
                                              <br>
                                              On 04/02/2016 08:19 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
                                                    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:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style: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:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style: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:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
                                                      <div bgcolor="#FFFFFF" text="#000000">
                                                        <div> Best
                                                          regards,<br>
                                                          Rongliang<br>
                                                          <br>
                                                          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:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style: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:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style: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-width:1px;border-left-style:solid;border-left-color: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-width:1px;border-left-style:solid;border-left-color: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-width:1px;border-left-style:solid;border-left-color: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-width:1px;border-left-style:solid;border-left-color: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><font color="#888888">
                                                          <span><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></font></span></div>
                                                          <span><font color="#888888">
                                                          </font></span></div>
                                                          <span><font color="#888888">
                                                          </font></span></blockquote>
                                                        <span><font color="#888888">
                                                          <br>
                                                          </font></span></div>
                                                      <span><font color="#888888">
                                                        </font></span></blockquote>
                                                    <span><font color="#888888">
                                                      </font></span></div>
                                                  <span><font color="#888888"> <br>
                                                      <br clear="all">
                                                      <span><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></font></span></div>
                                                <span><font color="#888888"> </font></span></div>
                                              <span><font color="#888888"> </font></span></blockquote>
                                            <span><font color="#888888">
                                                <br>
                                              </font></span></div>
                                          <span><font color="#888888"> </font></span></blockquote>
                                        <span><font color="#888888"> </font></span></div>
                                      <span><font color="#888888"> <br>
                                          <br clear="all">
                                          <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"><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><span class="HOEnZb"><font color="#888888">
                      </font></span></div><span class="HOEnZb"><font color="#888888">
                    </font></span></blockquote><span class="HOEnZb"><font color="#888888">
                    <br>
                  </font></span></div><span class="HOEnZb"><font color="#888888">
                </font></span></div><span class="HOEnZb"><font color="#888888">
              </font></span></div><span class="HOEnZb"><font color="#888888">
            </font></span></blockquote><span class="HOEnZb"><font color="#888888">
          </font></span></div><span class="HOEnZb"><font color="#888888">
          <br>
          <br clear="all">
          <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>