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authorEric Andersen <andersen@codepoet.org>2001-05-10 00:40:28 +0000
committerEric Andersen <andersen@codepoet.org>2001-05-10 00:40:28 +0000
commit1077fa4d772832f77a677ce7fb7c2d513b959e3f (patch)
tree579bee13fb0b58d2800206366ec2caecbb15f3fc /libm/ldouble/gdtrl.c
parent22358dd7ce7bb49792204b698f01a6f69b9c8e08 (diff)
uClibc now has a math library. muahahahaha!
-Erik
Diffstat (limited to 'libm/ldouble/gdtrl.c')
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+/* gdtrl.c
+ *
+ * Gamma distribution function
+ *
+ *
+ *
+ * SYNOPSIS:
+ *
+ * long double a, b, x, y, gdtrl();
+ *
+ * y = gdtrl( a, b, x );
+ *
+ *
+ *
+ * DESCRIPTION:
+ *
+ * Returns the integral from zero to x of the gamma probability
+ * density function:
+ *
+ *
+ * x
+ * b -
+ * a | | b-1 -at
+ * y = ----- | t e dt
+ * - | |
+ * | (b) -
+ * 0
+ *
+ * The incomplete gamma integral is used, according to the
+ * relation
+ *
+ * y = igam( b, ax ).
+ *
+ *
+ * ACCURACY:
+ *
+ * See igam().
+ *
+ * ERROR MESSAGES:
+ *
+ * message condition value returned
+ * gdtrl domain x < 0 0.0
+ *
+ */
+ /* gdtrcl.c
+ *
+ * Complemented gamma distribution function
+ *
+ *
+ *
+ * SYNOPSIS:
+ *
+ * long double a, b, x, y, gdtrcl();
+ *
+ * y = gdtrcl( a, b, x );
+ *
+ *
+ *
+ * DESCRIPTION:
+ *
+ * Returns the integral from x to infinity of the gamma
+ * probability density function:
+ *
+ *
+ * inf.
+ * b -
+ * a | | b-1 -at
+ * y = ----- | t e dt
+ * - | |
+ * | (b) -
+ * x
+ *
+ * The incomplete gamma integral is used, according to the
+ * relation
+ *
+ * y = igamc( b, ax ).
+ *
+ *
+ * ACCURACY:
+ *
+ * See igamc().
+ *
+ * ERROR MESSAGES:
+ *
+ * message condition value returned
+ * gdtrcl domain x < 0 0.0
+ *
+ */
+
+/* gdtrl() */
+
+
+/*
+Cephes Math Library Release 2.3: March, 1995
+Copyright 1984, 1995 by Stephen L. Moshier
+*/
+
+#include <math.h>
+#ifdef ANSIPROT
+extern long double igaml ( long double, long double );
+extern long double igamcl ( long double, long double );
+#else
+long double igaml(), igamcl();
+#endif
+
+long double gdtrl( a, b, x )
+long double a, b, x;
+{
+
+if( x < 0.0L )
+ {
+ mtherr( "gdtrl", DOMAIN );
+ return( 0.0L );
+ }
+return( igaml( b, a * x ) );
+}
+
+
+
+long double gdtrcl( a, b, x )
+long double a, b, x;
+{
+
+if( x < 0.0L )
+ {
+ mtherr( "gdtrcl", DOMAIN );
+ return( 0.0L );
+ }
+return( igamcl( b, a * x ) );
+}