[petsc-users] SIGSEGV in Superlu_dist

[Anthony Haas]

Hi Sherry,

I recently submitted a matrix for which I noticed that Superlu_dist was 
hanging when running on 4 processors with parallel symbolic 
factorization. I have been using the latest version of Superlu_dist and 
the code is not hanging anymore. However, I noticed that when running 
the same matrix (I have attached the matrix), the code crashes with the 
following SIGSEGV when running on 10 procs (with or without parallel 
symbolic factorization). It is probably overkill to run such a 'small' 
matrix on 10 procs but I thought that it might still be useful to report 
the problem?? See below for the error obtained when running with gdb and 
also a code snippet to reproduce the error.

Thanks,


Anthony



1) ERROR in GDB

Program received signal SIGSEGV, Segmentation fault.
0x00007fe6ba609297 in MatLUFactorNumeric_SuperLU_DIST (F=0x1922b50,
     A=0x14a6a70, info=0x19099f8)
     at 
/home/anthony/LIB/petsc-3.6.1/src/mat/impls/aij/mpi/superlu_dist/superlu_dist.c:368
368           colA_start = rstart + ajj[0]; /* the smallest global col 
index of A */
(gdb)



2) PORTION OF CODE TO REPRODUCE ERROR

     Subroutine HowBigLUCanBe(rank)

       IMPLICIT NONE

       integer(i4b),intent(in) :: rank
       integer(i4b)            :: i,ct
       real(dp)                :: begin,endd
       complex(dpc)            :: sigma

       PetscErrorCode ierr


       if (rank==0) call cpu_time(begin)

       if (rank==0) then
          write(*,*)
          write(*,*)'Testing How Big LU Can Be...'
          write(*,*)'============================'
          write(*,*)
       endif

       !sigma = (1.0d0,0.0d0)
       !call MatAXPY(A,-sigma,B,DIFFERENT_NONZERO_PATTERN,ierr) ! on 
exit A = A-sigma*B

       !call MatView(A,PETSC_VIEWER_STDOUT_WORLD,ierr)

!.....Write Matrix to ASCII and Binary Format
       !call PetscViewerASCIIOpen(PETSC_COMM_WORLD,"Amat.m",viewer,ierr)
       !call MatView(DXX,viewer,ierr)
       !call PetscViewerDestroy(viewer,ierr)

       !call 
PetscViewerBinaryOpen(PETSC_COMM_WORLD,"Amat_binary.m",FILE_MODE_WRITE,viewer,ierr)
       !call MatView(A,viewer,ierr)
       !call PetscViewerDestroy(viewer,ierr)

!...Load a Matrix in Binary Format
       call 
PetscViewerBinaryOpen(PETSC_COMM_WORLD,"Amat_binary.m",FILE_MODE_READ,viewer,ierr)
       call MatCreate(PETSC_COMM_WORLD,DLOAD,ierr)
       call MatSetType(DLOAD,MATAIJ,ierr)
       call MatLoad(DLOAD,viewer,ierr)
       call PetscViewerDestroy(viewer,ierr)

       !call MatView(DLOAD,PETSC_VIEWER_STDOUT_WORLD,ierr)


!.....Create Linear Solver Context
       call KSPCreate(PETSC_COMM_WORLD,ksp,ierr)

!.....Set operators. Here the matrix that defines the linear system also 
serves as the preconditioning matrix.
       !call KSPSetOperators(ksp,A,A,DIFFERENT_NONZERO_PATTERN,ierr) 
!aha commented and replaced by next line

       !call KSPSetOperators(ksp,A,A,ierr) ! remember: here A = A-sigma*B
       call KSPSetOperators(ksp,DLOAD,DLOAD,ierr) ! remember: here A = 
A-sigma*B

!.....Set Relative and Absolute Tolerances and Uses Default for 
Divergence Tol
       tol = 1.e-10
       call 
KSPSetTolerances(ksp,tol,tol,PETSC_DEFAULT_REAL,PETSC_DEFAULT_INTEGER,ierr)

!.....Set the Direct (LU) Solver
       call KSPSetType(ksp,KSPPREONLY,ierr)
       call KSPGetPC(ksp,pc,ierr)
       call PCSetType(pc,PCLU,ierr)
       call PCFactorSetMatSolverPackage(pc,MATSOLVERSUPERLU_DIST,ierr) ! 
MATSOLVERSUPERLU_DIST MATSOLVERMUMPS

!.....Create Right-Hand-Side Vector
       !call MatCreateVecs(A,frhs,PETSC_NULL_OBJECT,ierr)
       !call MatCreateVecs(A,sol,PETSC_NULL_OBJECT,ierr)

       call MatCreateVecs(DLOAD,frhs,PETSC_NULL_OBJECT,ierr)
       call MatCreateVecs(DLOAD,sol,PETSC_NULL_OBJECT,ierr)

       call MatGetOwnershipRange(DLOAD,IstartA,IendA,ierr)!;CHKERRQ(ierr)

       allocate(xwork1(IendA-IstartA))
       allocate(loc(IendA-IstartA))

       ct=0
       do i=IstartA,IendA-1
          ct=ct+1
          loc(ct)=i
          xwork1(ct)=(1.0d0,0.0d0)
       enddo

       call VecSetValues(frhs,IendA-IstartA,loc,xwork1,INSERT_VALUES,ierr)
       call VecZeroEntries(sol,ierr)

       deallocate(xwork1,loc)

!.....Assemble Vectors
       call VecAssemblyBegin(frhs,ierr)
       call VecAssemblyEnd(frhs,ierr)

!.....Solve the Linear System
       call KSPSolve(ksp,frhs,sol,ierr)

       !call VecView(sol,PETSC_VIEWER_STDOUT_WORLD,ierr)

       if (rank==0) then
          call cpu_time(endd)
          write(*,*)
          print '("Total time for HowBigLUCanBe = ",f21.3," 
seconds.")',endd-begin
       endif

       call SlepcFinalize(ierr)

       STOP


     end Subroutine HowBigLUCanBe

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