[cig-commits] [commit] knepley/fix-dm-composition, next: Solver: Remove DM from Vecs used in MatNullSpace - This avoids a reference cycle (6753495)

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Repository : https://github.com/geodynamics/pylith

On branches: knepley/fix-dm-composition,next
Link       : https://github.com/geodynamics/pylith/compare/9e9b3eb32aeee3851bb285945375cc28a2c0fdcf...ffaa715d19b1a8a79173ca5af7d64b65529244c8

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commit 6753495fc98dd431738ab42abd96f19b223fb39f
Author: Matthew G. Knepley <knepley at gmail.com>
Date:   Wed Jun 25 17:16:01 2014 -0700

    Solver: Remove DM from Vecs used in MatNullSpace
    - This avoids a reference cycle


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6753495fc98dd431738ab42abd96f19b223fb39f
 libsrc/pylith/problems/Solver.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libsrc/pylith/problems/Solver.cc b/libsrc/pylith/problems/Solver.cc
index ad906fc..fa9f6eb 100644
--- a/libsrc/pylith/problems/Solver.cc
+++ b/libsrc/pylith/problems/Solver.cc
@@ -178,6 +178,8 @@ pylith::problems::Solver::_createNullSpace(const topology::SolutionFields& field
     const int m = (spaceDim * (spaceDim + 1)) / 2;
     for(int i = 0; i < m; ++i) {
       err = VecDuplicate(solutionGlobalVec, &mode[i]);PYLITH_CHECK_ERROR(err);
+      // This is necessary to avoid circular references when we compose this MatNullSpace with a field in the DM
+      err = VecSetDM(mode[i], NULL);PYLITH_CHECK_ERROR(err);
     } // for
     // :KLUDGE: Assume P1
     for(int d = 0; d < spaceDim; ++d) {