c vector_prod.shl
c
c#>            vector_prod.dc3
c
cDocument:     VECTOR_PROD
c
cPurpose:      Contains the IRAS vector_*prod routines.
c
cCategory:     IRAS
c
cFile:         vector_prod.shl
c
cAuthor:       D. Kester
c
cDescription:  Refer to original documents. At the moment the modules
c              contained are vector_inprod and vector_outprod.
c
cUpdates:      Jul 15, 1991: KGB, Document created.
c
c#<
c
c@ double precision function vector_inprod( double precision, 
c@					    double precision )
c@ subroutine vector_outprod( double precision, double precision,
c@			      double precision )

c#>             vector_inprod.dc2
c Function:	VECTOR_INPROD
c
c Purpose:      Compute Vector Inner Product
c
c File:		vector_prod.shl
c
c Class:	Math
c
cAuthor:       Albrecht de Jonge
c
c Use: doubleprecision function VECTOR_INPROD( 
c	X,	I	doubleprecision
c	Y )  	I	doubleprecision
c
c       X, Y            two 3-dimensional vectors
c       VECTOR_INPROD   the inner product ( X dot Y )
c 
c       Mainly meant as a shorthand for
c               P = X(1) * Y(1) + X(2) * Y(2) + X(3) * Y(3)
c 
c Update        901113 DK, adapted to GIPSY
c#<

        doubleprecision function VECTOR_INPROD( X, Y )

	doubleprecision X(3), Y(3)

	VECTOR_INPROD = X(1) * Y(1) + X(2) * Y(2) + X(3) * Y(3)

	return
	end

c#>             vector_outprod.dc2
c Subroutine:	VECTOR_OUTPROD
c
c Purpose:      Compute Vector Outer Product
c
c File:		vector_prod.shl
c
c Class:	Math
c
cAuthor:	 Albrecht de Jonge
c
c Use: subroutine VECTOR_OUTPROD( 
c	X, Y, 	I	doubleprecision(3)
c	Z )	O	doubleprecision(3)
c
c       X, Y   	two 3-dimensional vectors
c       Z      	the outer product ( X cross Y )
c 
c       Mainly meant as a shorthand for
c               Z(1) = X(2) * Y(3) - X(3) * Y(2)
c               Z(2) = X(3) * Y(1) - X(1) * Y(3)
c               Z(3) = X(1) * Y(2) - X(2) * Y(1)
c 
c       The arguments may not share storage.
c 
c Update        901113 DK, adapted to GIPSY
c#<

       	subroutine VECTOR_OUTPROD( X, Y, Z )

	doubleprecision X(3), Y(3), Z(3)

	Z(1) = X(2) * Y(3) - X(3) * Y(2)
	Z(2) = X(3) * Y(1) - X(1) * Y(3)
	Z(3) = X(1) * Y(2) - X(2) * Y(1)

	return
	end