c****************************************************************
	
	subroutine schbasis(ptm,r_sch,r_xyzschmat,r_schxyzmat)
	
c****************************************************************
c**     
c**	FILE NAME: schbasis.f
c**     
c**     DATE WRITTEN: 10/01/97 
c**     
c**     PROGRAMMER: Scott Hensley
c**     
c** 	FUNCTIONAL DESCRIPTION: This routine computes the transformation
c**     matrix from xyz to a local sch frame. 
c**     
c**     ROUTINES CALLED:
c**  
c**     NOTES: none
c**
c**     UPDATE LOG:
c**
c*****************************************************************

       	implicit none

c	INPUT VARIABLES:

	type pegtrans
          sequence
	  real (8) r_mat(3,3)
	  real (8) r_matinv(3,3)
	  real (8) r_ov(3)
	  real (8) r_radcur
        end type pegtrans

	type (pegtrans) ptm

	real*8 r_sch(3)                  !SCH position
   
c   	OUTPUT VARIABLES:

	real*8 r_xyzschmat(3,3)
	real*8 r_schxyzmat(3,3)

c	LOCAL VARIABLES:

        real*8  r_coss,r_cosc,r_sins,r_sinc
	real*8 r_matschxyzp(3,3)

c	DATA STATEMENTS: none

C	FUNCTION STATEMENTS:

c  	PROCESSING STEPS:

c       compute transformation from a sch local basis to X'Y'Z' basis

	r_coss = cos(r_sch(1)/ptm%r_radcur)
	r_sins = sin(r_sch(1)/ptm%r_radcur)

	r_cosc = cos(r_sch(2)/ptm%r_radcur)
	r_sinc = sin(r_sch(2)/ptm%r_radcur)

	r_matschxyzp(1,1) = -r_sins 
	r_matschxyzp(1,2) = -r_sinc*r_coss
	r_matschxyzp(1,3) = r_coss*r_cosc
	r_matschxyzp(2,1) = r_coss
	r_matschxyzp(2,2) = -r_sinc*r_sins
	r_matschxyzp(2,3) = r_sins*r_cosc
	r_matschxyzp(3,1) = 0.0
	r_matschxyzp(3,2) = r_cosc
	r_matschxyzp(3,3) = r_sinc
	
c       compute sch to xyz matrix

        call matmat(ptm%r_mat,r_matschxyzp,r_schxyzmat)

c       get the inverse

	call tranmat(r_schxyzmat,r_xyzschmat)

        end