cr_spline_length.F File Reference

#include "implicit_f.inc"

Go to the source code of this file.

Functions/Subroutines
subroutine	cr_spline_length (local_pt, alpha, t, len)

Function/Subroutine Documentation

cr_spline_length()

subroutine cr_spline_length	(	dimension(4,3), intent(in)	local_pt,
		intent(in)	alpha,
		intent(in)	t,
		intent(inout)	len )

Definition at line 31 of file cr_spline_length.F.

C-----------------------------------------------
C   D e s c r i p t i o n
C-----------------------------------------------
        !compute SPLINE length with third order method (SIMPSON)
        !  INPUT  - LOCAL_PT : 4 control points P0,P1,P2,P3
        !  INPUT  - ALPHA : CCR SPLINE PARAMETER
        !  INPUT  - T : position [0,1] on SPLINE [T1,T2].  1.0 means full spline length
        !  OUTPUT - LEN : length of the curve parametrised with t in [0,T]  T<=1.0
C-----------------------------------------------
C   I m p l i c i t   T y p e s
C-----------------------------------------------
#include      "implicit_f.inc"
C-----------------------------------------------
C   D u m m y   A r g u m e n t s
C-----------------------------------------------
        my_real,INTENT(IN)    :: local_pt(4,3),alpha ,t
        my_real,INTENT(INOUT) :: len
C-----------------------------------------------
C   L o c a l   V a r i a b l e s
C-----------------------------------------------
        my_real               :: knots(4),c(3),c_d(3),c_dd(3),t_
        my_real               :: val(6),k(2)
        INTEGER            :: ITER,NITER
C-----------------------------------------------
C   S o u r c e   L i n e s
C-----------------------------------------------
        CALL cr_spline_knots(local_pt, knots, alpha)
        len = 0.
        niter=20
        DO iter=1,niter-1
          !first point
          t_=t*(1.*iter-1.)/(niter-1.)
          CALL cr_spline_interpol(local_pt,knots,t_,c,c_d,c_dd)
          val(1)=sqrt(dot_product(c_d(1:3),c_d(1:3)))
          k(1)=knots(2)+t_*(knots(3)-knots(2))
          !middle point
          t_=(1.*iter-1.)/(1.*niter-1.) + 0.5*1./(niter-1.)
          t_=t_*t
          CALL cr_spline_interpol(local_pt,knots,t_,c,c_d,c_dd)
          val(2)=sqrt(dot_product(c_d(1:3),c_d(1:3)))
          !last point
          t_=t*(1.*iter)/(niter-1.)
          CALL cr_spline_interpol(local_pt,knots,t_,c,c_d,c_dd)
          val(3)=sqrt(dot_product(c_d(1:3),c_d(1:3)))
          k(2)=knots(2)+t_*(knots(3)-knots(2))
          !length
          len = len+(k(2)-k(1))/6. * (val(1)+4.*val(2)+val(3))
        ENDDO