Files
simpeg/SimPEG/Utils/TriSolve.f
T
2014-01-16 13:22:46 -08:00

65 lines
1.5 KiB
FortranFixed

c File TriSolve.f
subroutine forward(al, ial, jal, b, nv, n, nRHS, x)
double precision al(nv)
integer ial(n+1)
integer jal(nv)
double precision b(n,nRHS)
double precision x(n,nRHS)
integer nv
integer n
integer nRHS
integer rhs
cf2py intent(in) :: al
cf2py intent(in) :: ial
cf2py intent(in) :: jal
cf2py intent(in) :: b
cf2py intent(in) :: nv
cf2py intent(in) :: n
cf2py intent(in) :: nRHS
cf2py intent(out) :: x
real ( kind = 8 ) t
do rhs = 1, nRHS
do k = 1, n
t = b(k,rhs)
do j = ial(k)+1, ial(k+1)
t = t - al(j) * x(jal(j)+1,rhs)
end do
x(k,rhs) = t/al(ial(k+1))
end do
end do
end subroutine forward
subroutine backward(au,iau, jau, b, nv, n, nRHS, x)
double precision au(nv)
integer iau(n+1)
integer jau(nv)
double precision b(n,nRHS)
double precision x(n,nRHS)
integer nv
integer n
integer nRHS
integer rhs
cf2py intent(in) :: au
cf2py intent(in) :: iau
cf2py intent(in) :: jau
cf2py intent(in) :: b
cf2py intent(in) :: nv
cf2py intent(in) :: n
cf2py intent(in) :: nRHS
cf2py intent(out) :: x
real ( kind = 8 ) t
do rhs = 1, nRHS
do k = n, 1, -1
t = b(k,rhs)
do j = iau(k)+1, iau(k+1)
t = t - au(j) * x(jau(j)+1,rhs)
end do
x(k,rhs) = t/au(iau(k)+1)
end do
end do
end subroutine backward