1 files changed, 81 insertions, 0 deletions
diff --git a/libm/double/simpsn.c b/libm/double/simpsn.c
new file mode 100644
index 000000000..4eb19460b
--- /dev/null
+++ b/libm/double/simpsn.c
@@ -0,0 +1,81 @@
+/*							simpsn.c	*/
+/* simpsn.c
+ * Numerical integration of function tabulated
+ * at equally spaced arguments
+ */
+
+/* Coefficients for Cote integration formulas */
+
+/* Note: these numbers were computed using 40-decimal precision. */
+
+#define NCOTE 8
+
+/* 6th order formula */
+/*
+static double simcon[] =
+{
+  4.88095238095238095E-2,
+  2.57142857142857142857E-1,
+  3.2142857142857142857E-2,
+  3.2380952380952380952E-1,
+};
+*/
+
+/* 8th order formula */
+static double simcon[] =
+{
+  3.488536155202821869E-2,
+  2.076895943562610229E-1,
+ -3.27336860670194003527E-2,
+  3.7022927689594356261E-1,
+ -1.6014109347442680776E-1,
+};
+
+/* 10th order formula */
+/*
+static double simcon[] =
+{
+  2.68341483619261397039E-2,
+  1.77535941424830313719E-1,
+ -8.1043570626903960237E-2,
+  4.5494628827962161295E-1,
+ -4.3515512265512265512E-1,
+  7.1376463043129709796E-1,
+};
+*/
+
+/*							simpsn.c 2	*/
+/* 20th order formula */
+/*
+static double simcon[] =
+{
+  1.182527324903160319E-2,
+  1.14137717644606974987E-1,
+ -2.36478370511426964E-1,
+  1.20618689348187566E+0,
+ -3.7710317267153304677E+0,
+  1.03367982199398011435E+1,
+ -2.270881584397951229796E+1,
+  4.1828057422193554603E+1,
+ -6.4075279490154004651555E+1,
+  8.279728347247285172085E+1,
+ -9.0005367135242894657916E+1,
+};
+*/
+
+/*							simpsn.c 3	*/
+double simpsn( f, delta )
+double f[];	/* tabulated function */
+double delta;	/* spacing of arguments */
+{
+extern double simcon[];
+double ans;
+int i;
+
+
+ans = simcon[NCOTE/2] * f[NCOTE/2];
+for( i=0; i < NCOTE/2; i++ )
+	ans += simcon[i] * ( f[i] + f[NCOTE-i] );
+
+return( ans * delta * NCOTE );
+}