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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <math/gsurfit.h>
include "dgsurfitdef.h"
# GSFIT -- Procedure to solve the normal equations for a surface.
# The inner products of the basis functions are calculated and
# accumulated into the GS_NCOEFF(sf) ** 2 matrix MATRIX.
# The main diagonal of the matrix is stored in the first row of
# MATRIX followed by the remaining non-zero diagonals.
# The inner product
# of the basis functions and the data ordinates are stored in the
# GS_NCOEFF(sf)-vector VECTOR. The Cholesky factorization of MATRIX
# is calculated and stored in CHOFAC. Forward and back substitution
# is used to solve for the GS_NCOEFF(sf)-vector COEFF.
procedure dgsfit (sf, x, y, z, w, npts, wtflag, ier)
pointer sf # surface descriptor
double x[npts] # array of x values
double y[npts] # array of y values
double z[npts] # data array
double w[npts] # array of weights
int npts # number of data points
int wtflag # type of weighting
int ier # ier = OK, everything OK
# ier = SINGULAR, matrix is singular, 1 or more
# coefficients are 0.
# ier = NO_DEG_FREEDOM, too few points to solve matrix
begin
call dgszero (sf)
call dgsacpts (sf, x, y, z, w, npts, wtflag)
call dgssolve (sf, ier)
end
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