Merge pull request #14444 from marcosvanella/master

FDS Source : ULMAT condense semi-positive matrix when using HYPRE.

Author: marcosvanella

Source/pres.f90

@@ -1702,6 +1702,7 @@ SUBROUTINE ULMAT_SOLVE_ZONE(NM,IPZ)
 #endif
 CASE(HYPRE_FLAG) LIBRARY_SELECT
 #ifdef WITH_HYPRE
+   IF (ZM%MTYPE==SYMM_INDEFINITE) ZM%F_H(ZM%NUNKH) = 0._EB
    CALL HYPRE_IJVECTORSETVALUES(ZM%HYPRE_ZM%F_H, ZM%NUNKH, ZM%HYPRE_ZM%INDICES, ZM%F_H, HYPRE_IERR)
    CALL HYPRE_IJVECTORASSEMBLE(ZM%HYPRE_ZM%F_H, HYPRE_IERR)
    CALL HYPRE_PARCSRPCGSOLVE(ZM%HYPRE_ZM%SOLVER, ZM%HYPRE_ZM%PARCSR_A_H, ZM%HYPRE_ZM%PAR_F_H, ZM%HYPRE_ZM%PAR_X_H, HYPRE_IERR)
@@ -2863,6 +2864,19 @@ SUBROUTINE ULMAT_H_MATRIX_SOLVER_SETUP(NM,IPZ)
    CALL HYPRE_IJMATRIXCREATE(MPI_COMM_SELF,0,ZM%NUNKH-1,0,ZM%NUNKH-1,ZM%HYPRE_ZM%A_H,HYPRE_IERR)
    CALL HYPRE_IJMATRIXSETOBJECTTYPE(ZM%HYPRE_ZM%A_H,HYPRE_PARCSR,HYPRE_IERR)
    CALL HYPRE_IJMATRIXINITIALIZE(ZM%HYPRE_ZM%A_H,HYPRE_IERR)
+   IF (ZM%MTYPE==SYMM_INDEFINITE) THEN
+      ! Rows 1 to ZM%NUNKH-1, last column, set all to zero:
+      DO IROW=1,ZM%NUNKH-1
+         DO JCOL=1,NNZ_H_MAT(IROW)
+            IF ( JD_H_MAT(JCOL,IROW) /= ZM%NUNKH ) CYCLE ! Make zero matrix entries in last column.
+            D_H_MAT(JCOL,IROW) = 0._EB
+         ENDDO
+      ENDDO
+      ! Last row, all zeros except the diagonal that keeps diagonal number: Note after previous loop IROW==ZM%NUNKH
+      DO JCOL=1,NNZ_H_MAT(IROW)
+         IF ( JD_H_MAT(JCOL,IROW) /= ZM%NUNKH ) D_H_MAT(JCOL,IROW) = 0._EB
+      ENDDO
+   ENDIF
    JD_H_MAT = JD_H_MAT - 1
    DO IROW=1,ZM%NUNKH
       ZM%HYPRE_ZM%INDICES(IROW)=IROW-1