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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include <math/curfit.h>
+
+include "curfitdef.h"
+
+
+# CVSOLVE -- Solve the matrix normal equations of the form ca = b for a,
+# where c is a symmetric, positive semi-definite, banded matrix with
+# CV_NCOEFF(cv) rows and a and b are CV_NCOEFF(cv)-vectors.
+# Initially c is stored in the CV_ORDER(cv) by CV_NCOEFF(cv) matrix MATRIX
+# and b is stored in VECTOR.
+# The Cholesky factorization of MATRIX is calculated and stored in CHOFAC.
+# Finally the coefficients are calculated by forward and back substitution
+# and stored in COEFF.
+
+procedure cvsolve (cv, ier)
+
+
+pointer	cv 		# curve descriptor
+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
+int	nfree
+
+begin
+	ier = OK
+	nfree = CV_NPTS(cv) - CV_NCOEFF(cv)
+
+	if (nfree < 0) {
+	    ier = NO_DEG_FREEDOM
+	    return
+	}
+
+	# calculate the Cholesky factorization of the data matrix
+	call rcvchofac (MATRIX(CV_MATRIX(cv)), CV_ORDER(cv), CV_NCOEFF(cv),
+		    CHOFAC(CV_CHOFAC(cv)), ier)
+
+	# solve for the coefficients by forward and back substitution
+	call rcvchoslv (CHOFAC(CV_CHOFAC(cv)), CV_ORDER(cv), CV_NCOEFF(cv),
+		    VECTOR(CV_VECTOR(cv)), COEFF(CV_COEFF(cv)))
+end