<br><br><div class="gmail_quote">On 16 June 2010 11:38, Matthew Knepley <span dir="ltr"><<a href="mailto:knepley@gmail.com">knepley@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Barry,<div><br></div><div> You inserted a check in VecAXPY:563 (which Jed corrected)</div><div><br></div><div><span style="font-family:sans-serif;font-size:12px"><table style="padding-top:8px;padding-right:4px;padding-bottom:8px;padding-left:4px">
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<a href="http://petsc/petsc-dev/annotate/c5b7ef1f9e2d/src/vec/vec/interface/rvector.c#l563" title="c5b7ef1f9e2d: Fix some misuse of SETERRQ, Barry was naughty and didn't compile" style="color:rgb(136, 0, 0)" target="_blank">jed@16195</a></td>
<td style="padding-top:2px;padding-right:5px;padding-bottom:2px;padding-left:5px;font-size:12px;vertical-align:top"><pre style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"><a href="#1294132b5614bbcc_l563" style="color:rgb(136, 0, 0);text-decoration:none"> 563</a></pre>
</td><td style="padding-top:2px;padding-right:5px;padding-bottom:2px;padding-left:5px;font-size:12px;vertical-align:top"><pre style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"> if (x == y) SETERRQ(((PetscObject)x)->comm,PETSC_ERR_ARG_IDN,"x and y cannot be the same vector");
</pre></td></tr><tr style="background-color:rgb(237, 236, 230);font-family:monospace"></tr></tbody></table><br></span></div><div><span style="font-family:sans-serif;font-size:12px">However, this seems to make no sense in light of mg.c:53</span></div>
<div><span style="font-family:sans-serif;font-size:12px"><br></span></div><div><span style="font-family:sans-serif;font-size:12px"><div> ierr = MatInterpolateAdd(mglevels->interpolate,mgc->x,mglevels->x,mglevels->x);CHKERRQ(ierr);</div>
<div><br></div><div>which will eventually call this with y == w, and has stack</div></span><div><br></div><div>0]PETSC ERROR: VecAXPY() line 563 in src/vec/vec/interface/rvector.c</div><div>[0]PETSC ERROR: MatMultAdd_ML() line 179 in src/ksp/pc/impls/ml/ml.c</div>
<div>[0]PETSC ERROR: MatMultAdd() line 2041 in src/mat/interface/matrix.c</div><div>[0]PETSC ERROR: MatInterpolateAdd() line 6535 in src/mat/interface/matrix.c</div><div>[0]PETSC ERROR: PCMGMCycle_Private() line 53 in src/ksp/pc/impls/mg/mg.c</div>
<div>[0]PETSC ERROR: PCMGMCycle_Private() line 50 in src/ksp/pc/impls/mg/mg.c</div><div>[0]PETSC ERROR: PCMGMCycle_Private() line 50 in src/ksp/pc/impls/mg/mg.c</div><div>[0]PETSC ERROR: PCApply_MG() line 288 in src/ksp/pc/impls/mg/mg.c</div>
<div>[0]PETSC ERROR: PCApply() line 358 in src/ksp/pc/interface/precon.c</div><div>[0]PETSC ERROR: KSPSolve_PREONLY() line 27 in src/ksp/ksp/impls/preonly/preonly.c</div><div>[0]PETSC ERROR: KSPSolve() line 427 in src/ksp/ksp/interface/itfunc.c</div>
<div>[0]PETSC ERROR: PCApply_FieldSplit() line 530 in src/ksp/pc/impls/fieldsplit/fieldsplit.c</div><div>[0]PETSC ERROR: PCApply() line 358 in src/ksp/pc/interface/precon.c</div><div>[0]PETSC ERROR: KSPInitialResidual() line 65 in src/ksp/ksp/interface/itres.c</div>
<div>[0]PETSC ERROR: KSPSolve_GMRES() line 236 in src/ksp/ksp/impls/gmres/gmres.c</div><div>[0]PETSC ERROR: KSPSolve() line 427 in src/ksp/ksp/interface/itfunc.c</div><div><br></div><div>Can I remove this check?</div><div>
<br></div><div> Thanks,</div><div><br></div><div> Matt</div><div><br></div>-- <br>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<br>
</div>
</blockquote></div><br>I think x==y have to be special-cased (potential issues with arg aliasing in BLAS?). What about: if (x==y) VecScale(x, 1+alpha)<br clear="all"><br>-- <br>Lisandro Dalcin<br>---------------<br>CIMEC (INTEC/CONICET-UNL)<br>
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