cr_spline_knots.F File Reference

#include "implicit_f.inc"

Go to the source code of this file.

Functions/Subroutines
subroutine	cr_spline_knots (pts, knots, alpha)

Function/Subroutine Documentation

cr_spline_knots()

subroutine cr_spline_knots	(	dimension(0:3,3), intent(in)	pts,
		dimension(0:3), intent(inout)	knots,
		intent(in)	alpha )

Definition at line 30 of file cr_spline_knots.F.

C-----------------------------------------------
C   I m p l i c i t   T y p e s
C-----------------------------------------------
#include      "implicit_f.inc"
C-----------------------------------------------
C   D e s c r i p t i o n
C-----------------------------------------------
        ! computes knots for solving 4-point spline path.
        ! CATMULL-ROM PARAMETER
        !  ALPHA = 0.0 : uniform
        !  ALPHA = 0.5 : centripetal
        !  ALPHA = 1.0 : chordal
        !      INPUT  - PTS(0:3,:) are 4 control points
        !      INPUT  - ALPHA CCR SPLINE PARAMETER
        !      OUTPU  - KNOTS() : t0,t1,t2,t3
C-----------------------------------------------
C   D u m m y   A r g u m e n t s
C-----------------------------------------------
        my_real, INTENT(IN)    :: pts(0:3,3),  alpha
        my_real, INTENT(INOUT) :: knots(0:3)
C-----------------------------------------------
C   L o c a l   V a r i a b l e s
C-----------------------------------------------
        my_real :: x,y,z
C-----------------------------------------------
C   S o u r c e   L i n e s
C-----------------------------------------------
        knots(0)=0.0
        x=pts(1-1,1)-pts(1,1)
        y=pts(1-1,2)-pts(1,2)
        z=pts(1-1,3)-pts(1,3)
        knots(1)=knots(0)+ exp(alpha*log(sqrt(x*x+y*y+z*z)))
        x=pts(1,1)-pts(1+1,1)
        y=pts(1,2)-pts(1+1,2)
        z=pts(1,3)-pts(1+1,3)
        knots(2)=knots(1)+ exp(alpha*log(sqrt(x*x+y*y+z*z)))
        x=pts(1+1,1)-pts(1+2,1)
        y=pts(1+1,2)-pts(1+2,2)
        z=pts(1+1,3)-pts(1+2,3)
        knots(3)=knots(2)+ exp(alpha*log(sqrt(x*x+y*y+z*z)))