Repatch (from linux) of OSX IRAF

1 files changed, 32 insertions, 0 deletions

diff --git a/pkg/utilities/nttools/trebin/tuispl.f b/pkg/utilities/nttools/trebin/tuispl.f
new file mode 100644
index 00000000..2f4c68b8
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+++ b/pkg/utilities/nttools/trebin/tuispl.f
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+	subroutine tuispl (xa, ya, y2, x, y)
+C
+C  Interpolate at point X using cubic splines.  The array Y2 must have
+C  previously been computed by calling TUCSPL.  Note that XA, YA, Y2
+C  are two-element subarrays of the arrays with the same names elsewhere.
+C  Input and output are all double precision.
+C  This routine was copied with slight modifications from the SPLINT
+C  subroutine in Numerical Recipes by Press, Flannery, Teukolsky and
+C  Vetterling.
+C
+C  XA		i: pair of independent-variable values
+C  YA		i: pair of dependent-variable values
+C  Y2		i: second derivatives of YA at each point
+C  X		i: value at which spline is to be computed
+C  Y		o: interpolated value at X
+C
+CH  Phil Hodge, 14-Apr-1988  Subroutine copied from Numerical Recipes SPLINT.
+C
+	double precision xa(2), ya(2), y2(2), x, y
+C--
+	double precision h, a, b
+
+	h = xa(2) - xa(1)
+
+	a = (xa(2) - x) / h
+	b = (x - xa(1)) / h
+	y = a * ya(1) + b * ya(2) +
+     +		((a**3 - a) * y2(1) + (b**3 - b) * y2(2))
+     +		* h * h / 6.
+
+	return
+	end