hecmw_ordering_rcm.f90

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!-------------------------------------------------------------------------------
! Copyright (c) 2020 FrontISTR Commons
! This software is released under the MIT License, see LICENSE.txt
!-------------------------------------------------------------------------------
 
!----------------------------------------------------------------------
!         for direct solver
!----------------------------------------------------------------------
module hecmw_ordering_rcm
  use hecmw_util
  implicit none
 
  private
  public :: hecmw_ordering_genrcm
 
contains
 
  subroutine hecmw_ordering_genrcm(Neqns,Xadj,Adj0,Perm,Invp)
    use m_hecmw_matrix_ordering_cm
    implicit none
    integer(kind=kint), intent(in):: neqns
    integer(kind=kint), intent(in):: adj0(:)
    integer(kind=kint), intent(in):: xadj(:)
    integer(kind=kint), intent(out):: perm(:)
    integer(kind=kint), intent(out):: invp(:)
    integer(kind=kint), allocatable:: indexl(:), indexu(:), itemu(:)
    integer(kind=kint) :: i
    allocate(indexl(0:neqns))
    allocate(indexu(0:neqns))
    allocate(itemu(1))
    ! 1-based numbering to 0-based numbering
    do i = 0, neqns
      indexl(i) = xadj(i+1)-1
    enddo
    ! empty index/item for upper triangle
    indexu(:) = 0
    itemu(:) = 0
    call hecmw_matrix_ordering_rcm(neqns, indexl, adj0, indexu, itemu, perm, invp)
    deallocate(indexl)
    deallocate(indexu)
    deallocate(itemu)
  end subroutine hecmw_ordering_genrcm
 
end module hecmw_ordering_rcm