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<p>Thanks, Barry.<br>
</p>
<p>Just to be sure, one should refer to the help of
<a class="moz-txt-link-freetext" href="https://urldefense.us/v3/__https://petsc.org/release/manualpages/DM/DMCreateInterpolationScale/__;!!G_uCfscf7eWS!c1PFRpf9jqVzaF3p98Od2T92U1LOgy4Q3oqZCcYrv2QsIO885A3iP7Lo3XpDveKwS7CMeHxzVseroufdL1mP8nbei0E_jEnpPsLtNQ$">https://petsc.org/release/manualpages/DM/DMCreateInterpolationScale/</a>
and the vec should be set to the point-wise inverse of
(INTERPOLATION)*(vector of ones) ?</p>
<div class="moz-cite-prefix">Matteo</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">On 10/12/2024 16:38, Barry Smith wrote:<br>
</div>
<blockquote type="cite" cite="mid:97C19201-BA91-4661-9E03-0CD1817AA663@petsc.dev">
<div><br>
</div>
It appears you are completely ignoring the vec argument? Take a
look at, for example, DMCreateInterpolation_DA() you will see you
need to provide an appropriate vec in the same way you need (and
do) provide an appropriate mat.
<div><br>
</div>
<div> Barry</div>
<div><br id="lineBreakAtBeginningOfMessage">
<div><br>
<blockquote type="cite">
<div>On Dec 10, 2024, at 7:02 AM, Matteo Semplice via
petsc-users <a class="moz-txt-link-rfc2396E" href="mailto:petsc-users@mcs.anl.gov"><petsc-users@mcs.anl.gov></a> wrote:</div>
<br class="Apple-interchange-newline">
<div>
<div>
<p>Dear petsc-users,</p>
<p> I am trying with a student to modify the MG
example 65 to use mat-shells instead of assembled
matrices. Our use case is for a method that will use
custom shell operators and shell
interpolation/restrictions.</p>
<p>To start we have modified ex65 and tried to replace
the standard restriction/interpolation with a shell
matrix that performs the same operations on the DMDA
grids.<br>
</p>
<p>I attach our modifications to ex65.</p>
<p>The problem is that the code sometimes completes
execution and sometimes errors out like<br>
</p>
<p><span style="font-family:monospace"><span style="background-color: rgb(255, 255, 255);">$
./ex65shell -ksp_monitor -pc_type mg -da_refine 2
-ksp_rtol 1e-1 </span><br>
>> Created DMshell 0x55bbc83c91a0
(0x55bbc8390a80) <br>
Calling KSPSolve from main <br>
computeRHS on grid 513 <br>
computeMatrix on grid 513 <br>
Inside Coarsen <br>
>> Created DMshell 0x55bbc84c5270
(0x55bbc84b2ff0) <br>
Inside Coarsen <br>
>> Created DMshell 0x55bbc84e0a30
(0x55bbc84bdb60) <br>
>> Create interpolation from
0x55bbc84c5270(0x55bbc84b2ff0) to
0x55bbc83c91a0(0x55bbc8390a80) <br>
<span style="font-weight:bold;color:#ff5454;background-color:#ffffff;">[0]PETSC
ERROR: --------------------- Error Message
--------------------------------------------------------------</span><span style="background-color: rgb(255, 255, 255);"> </span><br>
[0]PETSC ERROR: Invalid pointer <br>
[0]PETSC ERROR: Invalid Pointer to PetscObject:
Argument 'obj' (parameter # 1) <br>
[0]PETSC ERROR: See <a class="moz-txt-link-freetext" href="https://urldefense.us/v3/__https://petsc.org/release/faq/__;!!G_uCfscf7eWS!Y29qRoOD71oxcd-BQFTUohkIToMJNW3puZ3CerpZ6pBnecqhBQ8TBwhSnikLt4BYQTmsBgtKvoCFi-JuLXQAE_Oe_a_d2XOL8KvOmw$" moz-do-not-send="true">https://petsc.org/release/faq/</a>
for trouble shooting. <br>
[0]PETSC ERROR: Petsc Release Version 3.22.0,
unknown <br>
[0]PETSC ERROR: ./ex65shell with 1 MPI process(es)
and PETSC_ARCH on signalkuppe by matteo Tue Dec 10
12:55:12 2024 <br>
[0]PETSC ERROR: Configure options:
--prefix=/home/matteo/software/petscsaved/3.22-opt/
PETSC_DIR=/home/matteo/software/petsc
--PETSC_ARCH=dbg --with-debugging=1 --with-st<br>
rict-petscerrorcode --download-hdf5 --download-ml
--with-metis --with-parmetis --with-gmsh
--with-triangle --with-zlib
--with-p4est-dir=~/software/p4est/local/ <br>
[0]PETSC ERROR: #1 PetscObjectReference() at
/home/matteo/software/petsc/src/sys/objects/inherit.c:620
<br>
[0]PETSC ERROR: #2 PCMGSetRScale() at
/home/matteo/software/petsc/src/ksp/pc/impls/mg/mgfunc.c:394
<br>
[0]PETSC ERROR: #3 PCSetUp_MG() at
/home/matteo/software/petsc/src/ksp/pc/impls/mg/mg.c:998
<br>
[0]PETSC ERROR: #4 PCSetUp() at
/home/matteo/software/petsc/src/ksp/pc/interface/precon.c:1071
<br>
[0]PETSC ERROR: #5 KSPSetUp() at
/home/matteo/software/petsc/src/ksp/ksp/interface/itfunc.c:415
<br>
[0]PETSC ERROR: #6 KSPSolve_Private() at
/home/matteo/software/petsc/src/ksp/ksp/interface/itfunc.c:826
<br>
[0]PETSC ERROR: #7 KSPSolve() at
/home/matteo/software/petsc/src/ksp/ksp/interface/itfunc.c:1075
<br>
[0]PETSC ERROR: #8 main() at ../src/ex65shell.c:79 <br>
[0]PETSC ERROR: PETSc Option Table entries: <br>
[0]PETSC ERROR: -da_refine 2 (source: command line)
<br>
[0]PETSC ERROR: -ksp_monitor (source: command line)
<br>
[0]PETSC ERROR: -ksp_rtol 1e-1 (source: command
line) <br>
[0]PETSC ERROR: -pc_type mg (source: command line) <br>
<span style="font-weight:bold;color:#ff5454;background-color:#ffffff;">[0]PETSC
ERROR: ----------------End of Error Message
-------send entire error message to <a class="moz-txt-link-abbreviated moz-txt-link-freetext" href="mailto:petsc-maint@mcs.anl.gov" moz-do-not-send="true">petsc-maint@mcs.anl.gov</a>----------</span><br>
</span></p>
<p>In all cases valgrind complains like<br>
</p>
<p><span style="font-family:monospace"><span style="background-color: rgb(255, 255, 255);">$
valgrind ./ex65shell -ksp_monitor -pc_type mg
-da_refine 2 -ksp_rtol 1e-1 -int_view
ascii::ascii_info </span><br>
==2130767== Memcheck, a memory error detector <br>
==2130767== Copyright (C) 2002-2022, and GNU GPL'd,
by Julian Seward et al. <br>
==2130767== Using Valgrind-3.19.0 and LibVEX; rerun
with -h for copyright info <br>
==2130767== Command: ./ex65shell -ksp_monitor
-pc_type mg -da_refine 2 -ksp_rtol 1e-1 -int_view
ascii::ascii_info <br>
==2130767== <br>
hwloc x86 backend cannot work under Valgrind,
disabling. <br>
May be reenabled by dumping CPUIDs with
hwloc-gather-cpuid <br>
and reloading them under Valgrind with
HWLOC_CPUID_PATH. <br>
>> Created DMshell 0xfbf50f0 (0xfb49480) <br>
Calling KSPSolve from main <br>
computeRHS on grid 513 <br>
computeMatrix on grid 513 <br>
Inside Coarsen <br>
>> Created DMshell 0xff404a0 (0xff062d0) <br>
Inside Coarsen <br>
>> Created DMshell 0xff78ca0 (0xff4a530) <br>
>> Create interpolation from
0xff404a0(0xff062d0) to 0xfbf50f0(0xfb49480) <br>
Mat Object: 1 MPI process <br>
type: shell <br>
rows=513, cols=257 <br>
==2130767== Conditional jump or move depends on
uninitialised value(s) <br>
==2130767== at 0x83FDAAE: PCSetUp_MG (mg.c:998) <br>
==2130767== by 0x8620C04: PCSetUp (precon.c:1071)
<br>
==2130767== by 0x7DA78D5: KSPSetUp (itfunc.c:415)
<br>
==2130767== by 0x7DB2093: KSPSolve_Private
(itfunc.c:826) <br>
==2130767== by 0x7DB7A53: KSPSolve
(itfunc.c:1075) <br>
==2130767== by 0x10D2F7: main (ex65shell.c:79) <br>
==2130767== <br>
==2130767== Conditional jump or move depends on
uninitialised value(s) <br>
==2130767== at 0x5794061: VecDestroy
(vector.c:570) <br>
==2130767== by 0x83FDC36: PCSetUp_MG (mg.c:999) <br>
==2130767== by 0x8620C04: PCSetUp (precon.c:1071)
<br>
==2130767== by 0x7DA78D5: KSPSetUp (itfunc.c:415)
<br>
==2130767== by 0x7DB2093: KSPSolve_Private
(itfunc.c:826) <br>
==2130767== by 0x7DB7A53: KSPSolve
(itfunc.c:1075) <br>
==2130767== by 0x10D2F7: main (ex65shell.c:79) <br>
==2130767== <br>
</span></p>
<p>We are clearly doing something wrong since PCSetUp_MG
(mg.c:998) is an area of code where I wouldn't expect
we would enter.</p>
<p>Can you advise on the proper way to achieve our goal?<br>
</p>
<p>Best regards</p>
<p> Matteo<br>
</p>
</div>
<span id="cid:2ED6A6D4-97BD-49C4-B25B-EC46C444CE4F"><ex65.patch></span></div>
</blockquote>
</div>
<br>
</div>
</blockquote>
<pre class="moz-signature" cols="72">--
Prof. Matteo Semplice
Università degli Studi dell’Insubria
Dipartimento di Scienza e Alta Tecnologia – DiSAT
Professore Associato
Via Valleggio, 11 – 22100 Como (CO) – Italia
tel.: +39 031 2386316</pre>
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