Added nullspace support.

AMDiS/src/parallel/BddcMlSolver.cc

@@ -323,7 +323,7 @@ namespace AMDiS {
 
     int use_defaults_int = 1;
     int parallel_division_int = 1;
-    int use_arithmetic_int = 1;
+    int use_arithmetic_int = 0;
     int use_adaptive_int = 0;
     // MSG("call to \"bddcml_setup_preconditioner\" with the following arguments (each in one line):\n");
 //     MSG("  %d\n", matrixtype);

AMDiS/src/parallel/PetscSolver.cc

@@ -27,14 +27,16 @@ namespace AMDiS {
       coarseSpaceMap(NULL),
       mpiRank(-1),
       kspPrefix(""),
-      removeRhsNullSpace(false)
+      removeRhsNullspace(false),
+      hasConstantNullspace(false)
   {
     string kspStr = "";
     Parameters::get("parallel->solver->petsc->ksp", kspStr);
     if (kspStr != "")
       PetscOptionsInsertString(kspStr.c_str());
 
-    Parameters::get("parallel->remove rhs null space", removeRhsNullSpace);
+    Parameters::get("parallel->remove rhs null space", removeRhsNullspace);
+    Parameters::get("parallel->has constant null space", hasConstantNullspace);
   }
 
 

AMDiS/src/parallel/PetscSolver.h

@@ -116,9 +116,9 @@ namespace AMDiS {
       kspPrefix = s;
     }
 
-    void setRemoveRhsNullSpace(bool b)
+    void setRemoveRhsNullspace(bool b)
     {
-      removeRhsNullSpace = b;
+      removeRhsNullspace = b;
     }
 
     /// Adds a new vector to the basis of the operator's nullspace.
@@ -253,7 +253,9 @@ namespace AMDiS {
 
     /// If true, the constant null space is projected out of the RHS vector. It
     /// depends on the specific PETSc solver if it considers this value.
-    bool removeRhsNullSpace;
+    bool removeRhsNullspace;
+
+    bool hasConstantNullspace;
   };
 
 

AMDiS/src/parallel/PetscSolverGlobalMatrix.cc

@@ -363,19 +363,7 @@ namespace AMDiS {
 
     // === Remove Dirichlet BC DOFs. ===
     //    removeDirichletBcDofs(vec);
-
-  
-    // === Remove null space, if requested. ===
-
-    if (removeRhsNullSpace) {
-      TEST_EXIT_DBG(coarseSpaceMap == NULL)("Not supported!\n");
-
-      MSG("Remove constant null space from the RHS!\n");
-      MatNullSpace sp;
-      MatNullSpaceCreate(mpiCommGlobal, PETSC_TRUE, 0, PETSC_NULL, &sp);
-      MatNullSpaceRemove(sp, rhsInterior, PETSC_NULL);
-      MatNullSpaceDestroy(&sp);
-    }
+ 
   }
 
 
@@ -397,35 +385,53 @@ namespace AMDiS {
       VecAssemblyEnd(petscSolVec);
     }
 
-    MatNullSpace matNullSpace;
+
+    MatNullSpace matNullspace;
     Vec nullspaceBasis;
 
-    if (nullspace.size() > 0) {
-      TEST_EXIT_DBG(nullspace.size() == 1)("Not yet implemented!\n");
+    if (nullspace.size() > 0 || hasConstantNullspace) {
+      TEST_EXIT_DBG(nullspace.size() <= 1)("Not yet implemented!\n");
 
-      VecDuplicate(petscSolVec, &nullspaceBasis);
+      if (nullspace.size() > 0) {
+	VecDuplicate(petscSolVec, &nullspaceBasis);
+	for (int i = 0; i < nComponents; i++)
+	  setDofVector(nullspaceBasis, nullspace[0]->getDOFVector(i), i, true);
+	
+	VecAssemblyBegin(nullspaceBasis);
+	VecAssemblyEnd(nullspaceBasis);
+	
+	MatNullSpaceCreate(mpiCommGlobal, (hasConstantNullspace ? PETSC_TRUE : PETSC_FALSE), 
+			   1, &nullspaceBasis, &matNullspace);
 
-      for (int i = 0; i < nComponents; i++)
-	setDofVector(nullspaceBasis, nullspace[0]->getDOFVector(i), i, true);
+	MatMult(matIntInt, nullspaceBasis, petscSolVec);
+	PetscReal n;
+	VecNorm(petscSolVec, NORM_2, &n);
+	MSG("NORM IS: %e\n", n);
+      } else {
+	MatNullSpaceCreate(mpiCommGlobal, PETSC_TRUE, 0, PETSC_NULL, &matNullspace);
+      }
 
-      VecAssemblyBegin(nullspaceBasis);
-      VecAssemblyEnd(nullspaceBasis);
+      KSPSetNullSpace(kspInterior, matNullspace);
 
-      MatNullSpaceCreate(mpiCommGlobal, PETSC_FALSE, 1, &nullspaceBasis, &matNullSpace);
-      KSPSetNullSpace(kspInterior, matNullSpace);
+      // === Remove null space, if requested. ===
 
-      MatMult(matIntInt, nullspaceBasis, petscSolVec);
-      PetscReal n;
-      VecNorm(petscSolVec, NORM_2, &n);
-      MSG("NORM IS: %e\n", n);
+      if (removeRhsNullspace) {
+	TEST_EXIT_DBG(coarseSpaceMap == NULL)("Not supported!\n");
+	
+	MatNullSpaceRemove(matNullspace, rhsInterior, PETSC_NULL);
+      }
+    } else {
+      TEST_EXIT(removeRhsNullspace == false)
+	("No nullspace provided that should be removed from rhs!\n");
     }
 
+
     // PETSc.
     solve(rhsInterior, petscSolVec);
 
 
     if (nullspace.size() > 0) {
-      MatNullSpaceDestroy(&matNullSpace);
+      MatNullSpaceDestroy(&matNullspace);
       VecDestroy(&nullspaceBasis);
     }