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<div><span style="font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, "system-ui", Roboto, "Helvetica Neue", sans-serif; font-size: 15px; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">Pierre</span><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">,</span></div>
<div style="text-align: left; text-indent: 0px; margin: 0px;"><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">I can repeat your change in
</span><span style="font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, "system-ui", Roboto, "Helvetica Neue", sans-serif; font-size: 15px; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">ex27.c</span><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"> on
petsc-release. However, replacing </span></div>
<div style="text-align: left; text-indent: 0px; margin: 0px;"><span style="font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, "system-ui", Roboto, "Helvetica Neue", sans-serif; font-size: 15px; color: rgb(0, 0, 0);">+ Mat
D;</span></div>
<div style="text-align: left; text-indent: 0px; background-color: rgb(255, 255, 255); margin: 0px;">
<span style="font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, "system-ui", Roboto, "Helvetica Neue", sans-serif; font-size: 15px; color: rgb(0, 0, 0);">+ PetscCall(MatMatMult(C, C, MAT_INITIAL_MATRIX, PETSC_DECIDE, &D));</span></div>
<div style="text-align: left; text-indent: 0px; background-color: rgb(255, 255, 255); margin: 0px;">
<span style="font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, "system-ui", Roboto, "Helvetica Neue", sans-serif; font-size: 15px; color: rgb(0, 0, 0);">+ PetscCall(MatDestroy(&D));</span></div>
<div style="text-align: left; text-indent: 0px; background-color: rgb(255, 255, 255); margin: 0px;">
<span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">with</span></div>
<div style="text-align: left; text-indent: 0px; background-color: rgb(255, 255, 255); margin: 0px;">
<span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"> PetscCall(MatCreateNest(PETSC_COMM_WORLD, 2, NULL, 2, NULL, array, &C));</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">+ Mat D;</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">+ PetscCall(MatProductCreate(C, C, NULL, &D));</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">+ PetscCall(MatProductSetType(D, MATPRODUCT_AB));</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">+ PetscCall(MatProductSetFromOptions(D));</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">+ PetscCall(MatProductSymbolic(D));</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">+ PetscCall(MatProductNumeric(D));</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">+ PetscCall(MatDestroy(&D));</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">./ex27 -f farzad_B_rhs -truncate -solve_augmented</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">...</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">[0]PETSC ERROR: Petsc has generated inconsistent data</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">[0]PETSC ERROR: Unspecified symbolic phase for product AB with A nest, B nest. Call MatProductSetFromOptions()
first or the product is not supported</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">...</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">[0]PETSC ERROR: #1 MatProductSymbolic() at /Users/hongzhang-sun/soft/petsc/src/mat/interface/matproduct.c:807</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">[0]PETSC ERROR: #2 main() at ex27.c:250</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">i.e., same confusing error message as reported by Hana, because this calling process does not call MatProduct_Private()
with your fix. A fix to this is to modify the error message in </span><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 16px; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">MatProductSymbolic(</span><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">):</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">--- a/src/mat/interface/matproduct.c</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">+++ b/src/mat/interface/matproduct.c</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">@@ -804,7 +804,7 @@ PetscErrorCode MatProductSymbolic(Mat mat)</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"> ...</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">- PetscCheck(!missing, PetscObjectComm((PetscObject)mat), PETSC_ERR_PLIB, "Unspecified symbolic phase for
product %s. Call MatProductSetFromOptions() first", errstr);</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">+ PetscCheck(!missing, PetscObjectComm((PetscObject)mat), PETSC_ERR_PLIB, "Unspecified symbolic phase for
product %s. Call MatProductSetFromOptions() first </span><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(237, 92, 87);">or the product is not supported</span><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">",
errstr);</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">with this fix, I get </span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">./ex27 -f farzad_B_rhs -truncate -solve_augmented</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">...</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">[0]PETSC ERROR: Petsc has generated inconsistent data<br>
[0]PETSC ERROR: Unspecified symbolic phase for product AB with A nest, B nest. Call MatProductSetFromOptions() first or the product is not supported</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">If you agree with this fix, I'll create a MR for it.</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">Hong</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
</span></div>
<div style="text-align: left; text-indent: 0px; background-color: rgb(255, 255, 255); margin: 0px;">
<span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
</span></div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Pierre Jolivet <pierre@joliv.et><br>
<b>Sent:</b> Tuesday, February 13, 2024 12:08 AM<br>
<b>To:</b> Zhang, Hong <hzhang@mcs.anl.gov><br>
<b>Cc:</b> Hana Honnerová <hhornik@kma.zcu.cz>; petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov><br>
<b>Subject:</b> Re: [petsc-users] question on PCLSC with matrix blocks of type MATNEST</font>
<div> </div>
</div>
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<div><br>
<blockquote type="cite">
<div>On 13 Feb 2024, at 12:33 AM, Zhang, Hong <hzhang@mcs.anl.gov> wrote:</div>
<br class="x_Apple-interchange-newline">
<div>
<div class="x_elementToProof" style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none">
<span style="font-size:12px; background-color:rgb(255,255,255)">Pierre</span><span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">,</span></div>
<div class="x_elementToProof" style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none">
<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">I just modified the error message of MatProductSymbolic() and added a testing segment in src/mat/tests/ex195.c. I have not pushed my change yet.</span></div>
<div class="x_elementToProof" style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none">
<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt"><br>
</span></div>
<div class="x_elementToProof" style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none">
<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">Your fix<span class="x_Apple-converted-space"> </span></span><span style="font-size:12px; background-color:rgb(255,255,255)">at<span class="x_Apple-converted-space"> </span><a href="https://gitlab.com/petsc/petsc/-/commit/9dcea022de3b0309e5c16b8c554ad9c85dea29cf?merge_request_iid=7283" id="OWA6ac42782-786f-a866-5e9a-cd4b7e0eb6dc" class="x_OWAAutoLink" data-auth="NotApplicable" style="margin:0px; background-color:rgb(255,255,255); text-align:left">https://gitlab.com/petsc/petsc/-/commit/9dcea022de3b0309e5c16b8c554ad9c85dea29cf?merge_request_iid=7283</a></span><span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt"> is
more general. Has this fix merged to release and main? With latest main and release, I get same previous error message.</span></div>
</div>
</blockquote>
<div><br>
</div>
<div>I don’t (anymore, but could prior to my fix).</div>
<div>The trigger is MatMatMult() with MAT_INITIAL_MATRIX in PCSetUp_LSC().</div>
<div>Reproducible with:</div>
<div>
<div>diff --git a/src/ksp/ksp/tutorials/ex27.c b/src/ksp/ksp/tutorials/ex27.c</div>
<div>index 116b7df8522..9bdf4d7334a 100644</div>
<div>--- a/src/ksp/ksp/tutorials/ex27.c</div>
<div>+++ b/src/ksp/ksp/tutorials/ex27.c</div>
<div>@@ -245,2 +245,5 @@ int main(int argc, char **args)</div>
<div> PetscCall(MatCreateNest(PETSC_COMM_WORLD, 2, NULL, 2, NULL, array, &C));</div>
<div>+ Mat D;</div>
<div>+ PetscCall(MatMatMult(C, C, MAT_INITIAL_MATRIX, PETSC_DECIDE, &D));</div>
<div>+ PetscCall(MatDestroy(&D));</div>
<div> if (!sbaij) PetscCall(MatNestSetVecType(C, VECNEST));</div>
<div>Which now generates:</div>
<div>$ ./ex27 -f ${DATAFILESPATH}/matrices/farzad_B_rhs -truncate -solve_augmented </div>
<div>
<div>Failed to load RHS, so use a vector of all ones.</div>
<div>Failed to load initial guess, so use a vector of all zeros.</div>
<div>[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------</div>
<div>[0]PETSC ERROR: No support for this operation for this object type</div>
<div>[0]PETSC ERROR: MatProduct AB not supported for nest and nest</div>
<div>[0]PETSC ERROR: See https://petsc.org/release/faq/ for trouble shooting.</div>
<div><br>
</div>
</div>
<div>Thanks,</div>
<div>Pierre</div>
</div>
<br>
<blockquote type="cite">
<div>
<div class="x_elementToProof" style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none">
<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">Hong</span></div>
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<br>
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<span style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none; float:none; display:inline!important"></span>
<div id="x_divRplyFwdMsg" dir="ltr" style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none">
<span style="font-family:Calibri,sans-serif; font-size:11pt"><b>From:</b> Pierre Jolivet <pierre@joliv.et><br>
<b>Sent:</b> Sunday, February 11, 2024 7:43 AM<br>
<b>To:</b> Zhang, Hong <hzhang@mcs.anl.gov><br>
<b>Cc:</b> Hana Honnerová <hhornik@kma.zcu.cz>; petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov><br>
<b>Subject:</b> Re: [petsc-users] question on PCLSC with matrix blocks of type MATNEST</span>
<div> </div>
</div>
<div style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none">
<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt"><br>
</span></div>
<blockquote style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none">
<div><span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">On 8 Feb 2024, at 5:37 PM, Zhang, Hong via petsc-users <petsc-users@mcs.anl.gov> wrote:</span></div>
<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt"><br>
</span>
<div style="text-align:left; text-indent:0px; font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">
<span style="">Hana,</span></div>
<div style="text-align:left; text-indent:0px; font-family:Helvetica; font-size:12px">
<span style="font-size:15px; color:rgb(36,36,36); background-color:rgb(255,255,255)"><i>"product AB with A nest, B nest"</i></span><span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt"> is not supported
by PETSc. I do not know why PETSc does not display such an error message. I'll check it.</span></div>
</blockquote>
<div style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none">
<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt"><br>
</span></div>
<div style="font-family:Helvetica; font-size:12px; font-style:normal; font-variant-caps:normal; font-weight:400; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none">
<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">Did you?</span></div>
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<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">A naive fix is to simply add the missing PetscCheck() in MatProduct_Private() right after MatProductSetFromOptions()<a href="https://petsc.org/release/src/mat/interface/matrix.c.html#line10026" id="OWA467be896-3b4a-fcf1-068b-7c8059606479" class="x_OWAAutoLink" data-auth="NotApplicable">https://petsc.org/release/src/mat/interface/matrix.c.html#line10026</a> (notice
that it is there line 10048 in the other code branch)</span></div>
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<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">I have this at<span class="x_Apple-converted-space"> </span><a href="https://gitlab.com/petsc/petsc/-/commit/9dcea022de3b0309e5c16b8c554ad9c85dea29cf?merge_request_iid=7283" id="OWAbcb11c46-b85b-58bc-66c0-15ee4452eaf9" class="x_OWAAutoLink" data-auth="NotApplicable">https://gitlab.com/petsc/petsc/-/commit/9dcea022de3b0309e5c16b8c554ad9c85dea29cf?merge_request_iid=7283</a> (coupled
with code refactoring to avoid missing any other operations), but maybe we could do things more elegantly.</span></div>
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<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">Thanks,</span></div>
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<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">Pierre</span></div>
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<span style="font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif; font-size:12pt">Hong</span></div>
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<span style="font-family:Calibri,sans-serif; font-size:11pt"><b>From:</b> petsc-users <petsc-users-bounces@mcs.anl.gov> on behalf of Hana Honnerová <hhornik@kma.zcu.cz><br>
<b>Sent:</b> Thursday, February 8, 2024 4:45 AM<br>
<b>To:</b> petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov><br>
<b>Subject:</b> [petsc-users] question on PCLSC with matrix blocks of type MATNEST</span>
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<span style="font-family:Helvetica; font-size:12px">Hi all,</span></div>
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<span style="font-family:Helvetica; font-size:12px">I am trying to solve linear systems arising from isogeometric discretization (similar to FEM) of the Navier-Stokes equations in parallel using PETSc. The linear systems are of saddle-point type, so I would
like to use the PCFIELDSPLIT preconditioner with the -pc_fieldsplit_detect_saddle_point option, Schur complement factorization and the LSC Schur complement preconditioner. I do not provide any user-defined operators for PCLSC in my codes (at least for now).</span></div>
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<span style="font-family:Helvetica; font-size:12px">I store the matrix as a MATNEST consisting of 4 blocks (F for velocity-velocity part, Bt for velocity-pressure part, B for pressure-velocity part and NULL for pressure-pressure part). It is also convenient
for me to store the blocks F, Bt and B as another MATNEST consisting of blocks corresponding to individual velocity components. </span></div>
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However, in this setting, I get the following error message:</span></div>
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<span style="font-family:Helvetica; font-size:12px"><i>[0]PETSC ERROR: Petsc has generated inconsistent data<br>
[0]PETSC ERROR: Unspecified symbolic phase for product AB with A nest, B nest. Call MatProductSetFromOptions() first<br>
[0]PETSC ERROR: See<span class="x_Apple-converted-space"> </span><a href="https://petsc.org/release/faq/" id="OWA596b45ba-83bd-0021-639d-62eb4bf1bb47" class="x_x_x_moz-txt-link-freetext x_OWAAutoLink" data-auth="NotApplicable">https://petsc.org/release/faq/</a> for
trouble shooting.<br>
[0]PETSC ERROR: Petsc Release Version 3.20.4, unknown <br>
[0]PETSC ERROR: /home/hhornik/gismo/build-petsc-mpi/RelWithDebInfo/bin/gsINSSolverPETScTest on a arch-debug named ThinkPad-T14 by hhornik Thu Feb 8 11:04:17 2024<br>
[0]PETSC ERROR: Configure options PETSC_ARCH=arch-debug --with-debugging=1 --download-mumps --download-scalapack<br>
[0]PETSC ERROR: #1 MatProductSymbolic() at /home/hhornik/Software/PETSc/src/mat/interface/matproduct.c:807<br>
[0]PETSC ERROR: #2 MatProduct_Private() at /home/hhornik/Software/PETSc/src/mat/interface/matrix.c:10027<br>
[0]PETSC ERROR: #3 MatMatMult() at /home/hhornik/Software/PETSc/src/mat/interface/matrix.c:10103<br>
[0]PETSC ERROR: #4 PCSetUp_LSC() at /home/hhornik/Software/PETSc/src/ksp/pc/impls/lsc/lsc.c:79<br>
[0]PETSC ERROR: #5 PCSetUp() at /home/hhornik/Software/PETSc/src/ksp/pc/interface/precon.c:1080<br>
[0]PETSC ERROR: #6 KSPSetUp() at /home/hhornik/Software/PETSc/src/ksp/ksp/interface/itfunc.c:415<br>
[0]PETSC ERROR: #7 KSPSolve_Private() at /home/hhornik/Software/PETSc/src/ksp/ksp/interface/itfunc.c:832<br>
[0]PETSC ERROR: #8 KSPSolve() at /home/hhornik/Software/PETSc/src/ksp/ksp/interface/itfunc.c:1079<br>
[0]PETSC ERROR: #9 PCApply_FieldSplit_Schur() at /home/hhornik/Software/PETSc/src/ksp/pc/impls/fieldsplit/fieldsplit.c:1165<br>
[0]PETSC ERROR: #10 PCApply() at /home/hhornik/Software/PETSc/src/ksp/pc/interface/precon.c:498<br>
[0]PETSC ERROR: #11 KSP_PCApply() at /home/hhornik/Software/PETSc/include/petsc/private/kspimpl.h:383<br>
[0]PETSC ERROR: #12 KSPFGMRESCycle() at /home/hhornik/Software/PETSc/src/ksp/ksp/impls/gmres/fgmres/fgmres.c:123<br>
[0]PETSC ERROR: #13 KSPSolve_FGMRES() at /home/hhornik/Software/PETSc/src/ksp/ksp/impls/gmres/fgmres/fgmres.c:235<br>
[0]PETSC ERROR: #14 KSPSolve_Private() at /home/hhornik/Software/PETSc/src/ksp/ksp/interface/itfunc.c:906<br>
[0]PETSC ERROR: #15 KSPSolve() at /home/hhornik/Software/PETSc/src/ksp/ksp/interface/itfunc.c:1079<br>
[0]PETSC ERROR: #16 applySolver() at /home/hhornik/gismo/optional/gsIncompressibleFlow/src/gsINSSolver.hpp:531</i></span></div>
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</i>I could not find any solution for this so far. My question is: Is it possible to use the LSC preconditioner in such case, where the matrix blocks are of type MATNEST? And if so, how?</span></div>
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<span style="font-family:Helvetica; font-size:12px">Thank you,<br>
Hana Honnerova</span></div>
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