dslvd Subroutine

subroutine dslvd(neq, delta, rwm, iwm)

Uses

  • proc~~dslvd~~UsesGraph proc~dslvd dslvd module~daskr daskr proc~dslvd->module~daskr module~daskr_kinds daskr_kinds proc~dslvd->module~daskr_kinds module~linpack linpack proc~dslvd->module~linpack module~daskr->module~daskr_kinds iso_fortran_env iso_fortran_env module~daskr_kinds->iso_fortran_env module~linpack->module~daskr_kinds

This routine manages the solution of the linear system arising in the Newton iteration. Real matrix information and real temporary storage is stored in the array rwm, while integer matrix information is stored in the array iwm. For a dense matrix, the LINPACK routine dgesl is called. For a banded matrix, the LINPACK routine dgbsl is called.

Arguments

Type IntentOptional Attributes Name
integer, intent(in) :: neq

Problem size.
real(kind=rk), intent(inout) :: delta(neq)

On entry, the right-hand side vector of the linear system to be solved, and, on exit, the solution vector.
real(kind=rk), intent(inout) :: rwm(*)

Real workspace for the linear system solver.
integer, intent(inout) :: iwm(*)

Integer workspace for the linear system solver.

Calls

proc~~dslvd~~CallsGraph proc~dslvd dslvd proc~dgbsl dgbsl proc~dslvd->proc~dgbsl proc~dgesl dgesl proc~dslvd->proc~dgesl interface~daxpy daxpy proc~dgbsl->interface~daxpy interface~ddot ddot proc~dgbsl->interface~ddot

Variables

Type Visibility Attributes Name Initial
integer, public :: lipvt
integer, public :: meband
integer, public :: mtype

Source Code

subroutine dslvd(neq, delta, rwm, iwm)
!! This routine manages the solution of the linear system arising in the Newton iteration.
!! Real matrix information and real temporary storage is stored in the array `rwm`, while
!! integer matrix information is stored in the array `iwm`.
!! For a dense matrix, the LINPACK routine [[dgesl]] is called. For a banded matrix, the
!! LINPACK routine [[dgbsl]] is called.

   use daskr_kinds, only: rk
   use daskr
   use linpack, only: dgesl, dgbsl
   implicit none

   integer, intent(in) :: neq
      !! Problem size.
   real(rk), intent(inout) :: delta(neq)
      !! On entry, the right-hand side vector of the linear system to be solved,
      !! and, on exit, the solution vector.
   real(rk), intent(inout) :: rwm(*)
      !! Real workspace for the linear system solver.
   integer, intent(inout) :: iwm(*)
      !! Integer workspace for the linear system solver.

   integer :: lipvt, meband, mtype

   lipvt = iwm(iwloc_liwp)
   mtype = iwm(iwloc_mtype)

   select case (mtype)
   case (1, 2)
      ! dense matrix.
      call dgesl(rwm, neq, neq, iwm(lipvt), delta, 0)
   case (3)
      ! dummy section for mtype=3.
      error stop "error: mtype=3 not implemented"
   case (4, 5)
      ! banded matrix.
      meband = 2*iwm(iwloc_ml) + iwm(iwloc_mu) + 1
      call dgbsl(rwm, meband, neq, iwm(iwloc_ml), iwm(iwloc_mu), iwm(lipvt), delta, 0)
   case default
      error stop "error: unexpected value for mtype"
   end select

end subroutine dslvd