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SUBROUTINE sla_XY2XY (X1,Y1,COEFFS,X2,Y2)
*+
* - - - - - -
* X Y 2 X Y
* - - - - - -
*
* Transform one [X,Y] into another using a linear model of the type
* produced by the sla_FITXY routine.
*
* Given:
* X1 d x-coordinate
* Y1 d y-coordinate
* COEFFS d(6) transformation coefficients (see note)
*
* Returned:
* X2 d x-coordinate
* Y2 d y-coordinate
*
* The model relates two sets of [X,Y] coordinates as follows.
* Naming the elements of COEFFS:
*
* COEFFS(1) = A
* COEFFS(2) = B
* COEFFS(3) = C
* COEFFS(4) = D
* COEFFS(5) = E
* COEFFS(6) = F
*
* the present routine performs the transformation:
*
* X2 = A + B*X1 + C*Y1
* Y2 = D + E*X1 + F*Y1
*
* See also sla_FITXY, sla_PXY, sla_INVF, sla_DCMPF
*
* P.T.Wallace Starlink 5 December 1994
*
* Copyright (C) 1995 Rutherford Appleton Laboratory
*-
IMPLICIT NONE
DOUBLE PRECISION X1,Y1,COEFFS(6),X2,Y2
X2=COEFFS(1)+COEFFS(2)*X1+COEFFS(3)*Y1
Y2=COEFFS(4)+COEFFS(5)*X1+COEFFS(6)*Y1
END
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