<div dir="ltr"><div dir="ltr"><div class="gmail_default" style="font-family:"comic sans ms",sans-serif">Thanks.</div><div class="gmail_default" style="font-family:"comic sans ms",sans-serif"><br></div><div class="gmail_default"><font face="comic sans ms, sans-serif">Now I can run up to </font><span style="font-family:Arial,Helvetica,sans-serif">n=10^7 with </span><span style="font-family:Arial,Helvetica,sans-serif">-pc_type cholesky as well as </span>-pc_type hypre -pc_hypre_type boomeramg</div><div class="gmail_default"><br></div><div class="gmail_default">Actually, I trying to find how much time and FLOPs count does it take to solve a problem using multigrid for different sizes of the problem.</div><div class="gmail_default"><br></div><div class="gmail_default">The problem I am trying to solve is attached herewith. I am not quiet sure whether the way I have set the boundary conditions are correct or not! </div><div class="gmail_default">(Because, BCs are given for x0 and xn. I am solving for x1 to x(n-1). But setting BCs of x0 and xn)</div><div class="gmail_default"><br></div><div class="gmail_default">This would be a great help for me if you can refer me some books so that I can go through to make my understanding more clear.</div><div class="gmail_default"><br></div><div class="gmail_default">Thanks.</div><div class="gmail_default">Sincerely,</div><div class="gmail_default">Huq</div><div class="gmail_default"> </div></div></div><br><div class="gmail_quote"><div dir="ltr">On Fri, Nov 30, 2018 at 10:46 AM Jed Brown <<a href="mailto:jed@jedbrown.org">jed@jedbrown.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">"Smith, Barry F. via petsc-users" <<a href="mailto:petsc-users@mcs.anl.gov" target="_blank">petsc-users@mcs.anl.gov</a>> writes:<br>
<br>
> You need to run it on more processors, this one processor doesn't have enough memory to fit the vectors (which by the way are huge 1,614,907,707,076)<br>
<br>
This is just a tridiagonal problem; I don't know why the vectors would<br>
be huge when the problem dimension is only a million.<br>
<br>
Fazlul, is this your target problem? The tridiagonal problem can be<br>
solved trivially using Cholesky (-pc_type cholesky; or LU) -- the n=10^7<br>
case takes perhaps a second in serial (and this can be made faster).<br>
The convergence is slow with local preconditioners because information<br>
travels only one element at a time. Note that I don't get any<br>
memory-related error messages with a 32-bit build of PETSc, but perhaps<br>
I'm not running the same way as you are.<br>
<br>
The errors reported by your code are wrong because your stated exact<br>
solution and RHS are not actually compatible.<br>
<br>
> Barry<br>
><br>
><br>
>> On Nov 29, 2018, at 8:26 PM, Fazlul Huq <<a href="mailto:huq2090@gmail.com" target="_blank">huq2090@gmail.com</a>> wrote:<br>
>> <br>
>> Thanks.<br>
>> <br>
>> I have configured with 64-bit and then when I run, I got the following error message:<br>
>> ***********************************************************************************************************************<br>
>> [0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------<br>
>> [0]PETSC ERROR: Out of memory. This could be due to allocating<br>
>> [0]PETSC ERROR: too large an object or bleeding by not properly<br>
>> [0]PETSC ERROR: destroying unneeded objects.<br>
>> [0]PETSC ERROR: Memory allocated 41632 Memory used by process 13361152<br>
>> [0]PETSC ERROR: Try running with -malloc_dump or -malloc_log for info.<br>
>> [0]PETSC ERROR: Memory requested 1614907707076<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> for trouble shooting.<br>
>> [0]PETSC ERROR: Petsc Release Version 3.10.2, Oct, 09, 2018 <br>
>> [0]PETSC ERROR: ./poisson_m on a arch-linux2-c-debug named huq2090-XPS-15-9570 by huq2090 Thu Nov 29 20:24:13 2018<br>
>> [0]PETSC ERROR: Configure options --download-hypre --download-mpich --with-64-bit-indices<br>
>> [0]PETSC ERROR: #1 VecCreate_Seq() line 35 in /home/huq2090/petsc-3.10.2/src/vec/vec/impls/seq/bvec3.c<br>
>> [0]PETSC ERROR: #2 PetscTrMallocDefault() line 183 in /home/huq2090/petsc-3.10.2/src/sys/memory/mtr.c<br>
>> [0]PETSC ERROR: #3 PetscMallocA() line 397 in /home/huq2090/petsc-3.10.2/src/sys/memory/mal.c<br>
>> [0]PETSC ERROR: #4 VecCreate_Seq() line 35 in /home/huq2090/petsc-3.10.2/src/vec/vec/impls/seq/bvec3.c<br>
>> [0]PETSC ERROR: #5 VecSetType() line 51 in /home/huq2090/petsc-3.10.2/src/vec/vec/interface/vecreg.c<br>
>> [0]PETSC ERROR: #6 VecSetTypeFromOptions_Private() line 1250 in /home/huq2090/petsc-3.10.2/src/vec/vec/interface/vector.c<br>
>> [0]PETSC ERROR: #7 VecSetFromOptions() line 1284 in /home/huq2090/petsc-3.10.2/src/vec/vec/interface/vector.c<br>
>> [0]PETSC ERROR: #8 main() line 57 in /home/huq2090/petsc-3.10.2/problems/ksp/poisson_m.c<br>
>> [0]PETSC ERROR: No PETSc Option Table entries<br>
>> [0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-maint@mcs.anl.gov----------<br>
>> application called MPI_Abort(MPI_COMM_WORLD, 55) - process 0<br>
>> [unset]: write_line error; fd=-1 buf=:cmd=abort exitcode=55<br>
>> :<br>
>> system msg for write_line failure : Bad file descriptor<br>
>> ************************************************************************************************************************************<br>
>> <br>
>> Thanks.<br>
>> Sincerely,<br>
>> Huq<br>
>> <br>
>> On Thu, Nov 29, 2018 at 1:51 PM Smith, Barry F. <<a href="mailto:bsmith@mcs.anl.gov" target="_blank">bsmith@mcs.anl.gov</a>> wrote:<br>
>> <br>
>> <br>
>> > On Nov 29, 2018, at 1:46 PM, Fazlul Huq via petsc-users <<a href="mailto:petsc-users@mcs.anl.gov" target="_blank">petsc-users@mcs.anl.gov</a>> wrote:<br>
>> > <br>
>> > Hello PETSc Developers,<br>
>> > <br>
>> > I am trying to run the code (attached herewith) with the following command and it works until the size of the matrix is 99999X99999. But when I try to run with 999999X999999 then I got weird result.<br>
>> <br>
>> What is that "weird result"? <br>
>> <br>
>> My guess is for problems that large you need to ./configure PETSc with the additional option --with-64-bit-indices since for such large problems 32 bit integers are not large enough to contain values needed for storing and accessing the sparse matrix.<br>
>> <br>
>> Barry<br>
>> <br>
>> > <br>
>> > The command is: <br>
>> > ./poisson_m -n 999999 -pc_type hypre -pc_hypre_type boomeramg -ksp_view_solution<br>
>> > Any suggestions is appreciated.<br>
>> > <br>
>> > Thanks.<br>
>> > Sincerely,<br>
>> > Huq<br>
>> > <br>
>> > <br>
>> > -- <br>
>> > <br>
>> > Fazlul Huq<br>
>> > Graduate Research Assistant<br>
>> > Department of Nuclear, Plasma & Radiological Engineering (NPRE)<br>
>> > University of Illinois at Urbana-Champaign (UIUC)<br>
>> > E-mail: <a href="mailto:huq2090@gmail.com" target="_blank">huq2090@gmail.com</a><br>
>> > <poisson_m.c><br>
>> <br>
>> <br>
>> <br>
>> -- <br>
>> <br>
>> Fazlul Huq<br>
>> Graduate Research Assistant<br>
>> Department of Nuclear, Plasma & Radiological Engineering (NPRE)<br>
>> University of Illinois at Urbana-Champaign (UIUC)<br>
>> E-mail: <a href="mailto:huq2090@gmail.com" target="_blank">huq2090@gmail.com</a><br>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><br><div><font face="comic sans ms, sans-serif">Fazlul Huq</font></div><div><font face="comic sans ms, sans-serif">Graduate Research Assistant</font></div><div><font face="comic sans ms, sans-serif">Department of Nuclear, Plasma & Radiological Engineering (NPRE)</font></div><div><font face="comic sans ms, sans-serif">University of Illinois at Urbana-Champaign (UIUC)</font></div><div><font face="comic sans ms, sans-serif">E-mail: <a href="mailto:huq2090@gmail.com" target="_blank">huq2090@gmail.com</a></font></div></div></div></div></div></div></div>