Routines for getting the coefficients for the various derivatives. By request from Bela.

git-svn-id: https://svn.cct.lsu.edu/repos/numrel/LSUThorns/SummationByParts/trunk@23 f69c4107-0314-4c4f-9ad4-17e986b73f4a

1 files changed, 62 insertions, 0 deletions

diff --git a/src/Coefficients_2_1.F90 b/src/Coefficients_2_1.F90
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+++ b/src/Coefficients_2_1.F90
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+#include "cctk.h"
+#include "cctk_Functions.h"
+#include "cctk_Parameters.h"
+
+subroutine set_coeff_2_1 ( nsize, loc_order, bb, gsize, imin, imax, dd )
+
+  implicit none
+
+  DECLARE_CCTK_FUNCTIONS
+  DECLARE_CCTK_PARAMETERS
+
+  CCTK_REAL, parameter :: zero = 0.0
+  integer, parameter :: wp = kind(zero)
+  CCTK_INT, intent(IN) :: nsize, loc_order
+  CCTK_INT, dimension(2), intent(IN) :: bb
+  CCTK_INT, intent(IN) :: gsize
+  CCTK_INT, dimension(nsize), intent(OUT) :: imin, imax
+  CCTK_REAL, dimension(nsize,nsize), intent(OUT) :: dd
+
+  CCTK_REAL, dimension(1), save :: a
+  CCTK_REAL, dimension(3,2), save :: q 
+
+  CCTK_INT :: i, il, ir
+
+  logical, save :: first = .true.
+
+  if ( first ) then
+    a(1) = 1.0_wp/2.0_wp
+
+    q(1,1) = -1.0_wp; q(2,1) = 1.0_wp; q(3,1) = zero
+    q(1,2) = -1.0_wp/2.0_wp; q(2,2) = zero; q(3,2) = 1.0_wp/2.0_wp
+    first = .false.
+  end if
+
+  dd = zero
+  imin = 0
+  imax = -1
+
+  if ( bb(1) == 0 ) then
+    il = 1 + gsize
+  else
+    dd(1,1) = q(1,1); dd(2,1) = q(2,1)
+    imin(1) = 1; imax(1) = 2
+    dd(1,2) = q(1,2); dd(3,2) = q(3,2)
+    imin(2) = 1; imax(2) = 3
+    il = 3
+  end if
+  if ( bb(2) == 0 ) then
+    ir = nsize - gsize
+  else
+    dd(nsize-2,nsize-1) = -q(3,2); dd(nsize,nsize-1) = -q(1,2)
+    imin(nsize-1) = nsize-2; imax(nsize-1) = nsize
+    dd(nsize-1,nsize) = -q(2,1); dd(nsize,nsize) = -q(1,1)
+    imin(nsize) = nsize-1; imax(nsize) = nsize
+    ir = nsize - 2
+  end if
+  do i = il, ir
+    dd(i-1,i) = -a(1); dd(i+1,i) = a(1)
+    imin(i) = i-1; imax(i) = i+1
+  end do
+
+end subroutine set_coeff_2_1