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Diffstat (limited to 'math/gsurfit/gsgcoeffr.x')
| -rw-r--r-- | math/gsurfit/gsgcoeffr.x | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/math/gsurfit/gsgcoeffr.x b/math/gsurfit/gsgcoeffr.x new file mode 100644 index 00000000..45ef51e4 --- /dev/null +++ b/math/gsurfit/gsgcoeffr.x @@ -0,0 +1,45 @@ +# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc. + +include <math/gsurfit.h> +include "gsurfitdef.h" + +# GSGCOEFF -- Procedure to fetch a particular coefficient. +# If the requested coefficient is undefined then INDEF is returned. + +real procedure gsgcoeff (sf, xorder, yorder) + +pointer sf # pointer to the surface fitting descriptor +int xorder # X order of desired coefficent +int yorder # Y order of desired coefficent + +int i, n, maxorder, xincr + +begin + if ((xorder > GS_XORDER(sf)) || (yorder > GS_YORDER(sf))) + return (INDEFR) + + switch (GS_XTERMS(sf)) { + case GS_XNONE: + if (yorder == 1) + n = xorder + else if (xorder == 1) + n = GS_NXCOEFF(sf) + yorder - 1 + else + return (INDEFR) + case GS_XHALF: + maxorder = max (GS_XORDER(sf) + 1, GS_YORDER(sf) + 1) + if ((xorder + yorder) > maxorder) + return (INDEFR) + n = xorder + xincr = GS_XORDER(sf) + do i = 2, yorder { + n = n + xincr + if ((i + GS_XORDER(sf) + 1) > maxorder) + xincr = xincr - 1 + } + case GS_XFULL: + n = xorder + (yorder - 1) * GS_NXCOEFF(sf) + } + + return (COEFF(GS_COEFF(sf) + n - 1)) +end |