1 files changed, 117 insertions, 0 deletions
diff --git a/numlib/tdhsx.c b/numlib/tdhsx.c
new file mode 100644
index 0000000..d1738c4
--- /dev/null
+++ b/numlib/tdhsx.c
@@ -0,0 +1,117 @@
+
+/*
+ * Code to test the downhill simplex minimiser
+ *
+ * Copyright 1999 - 2005 Graeme W. Gill
+ * All rights reserved.
+ *
+ * This material is licenced under the GNU AFFERO GENERAL PUBLIC LICENSE Version 3 :-
+ * see the License.txt file for licencing details.
+ */
+
+#include <stdio.h>
+#include "numlib.h"
+
+/*       Final approximate solution:                                       */
+
+double expect[9] = {
+	-0.5706545E+00,
+	-0.6816283E+00,
+	-0.7017325E+00,
+	-0.7042129E+00,
+	-0.7013690E+00,
+	-0.6918656E+00,
+	-0.6657920E+00,
+	-0.5960342E+00,
+	-0.4164121E+00 };
+
+double fcn(		/* Return function value */
+	void *fdata,		/* Opaque data pointer */
+	double tp[]);		/* Multivriate input value */
+
+#define N 9
+
+int main(void)
+{
+	double cp[N];		/* Function input values */
+	double s[N];		/* Search area */
+	double err;
+	int j;
+	int nprint = 0;		/* Itteration debugging print = off */
+	int rv;
+
+	error_program = "tdhsx";	/* Set global error reporting string */
+
+	/*	 The following starting values provide a rough solution. */
+	for (j = 0; j < N; j++) {
+		cp[j] = -1.f;
+		s[j] = 0.9;
+	}
+
+	nprint = 0;
+
+	/*	 Set tol to the square root of the machine precision. */
+	/*	 Unless high precision solutions are required, */
+	/*	 this is the recommended setting. */
+
+	rv = dhsx(
+		&err,			/* return residual */
+		N, 				/* Dimentionality */
+		cp,				/* Initial starting point */
+		s,				/* Size of initial search area */
+		0.0000001,		/* Tollerance of error change to stop on */
+		1e6,			/* Absolute error to stop on */
+//		10.0,		/* Tollerance of error change to stop on */
+//		0.0001,			/* Absolute error to stop on */
+		1000,			/* Maximum iterations allowed */
+		fcn, 			/* Error function to evaluate */
+		NULL);			/* Opaque data needed by function */
+
+
+	fprintf(stdout,"Return code %d, residual err = %f:\n",rv, err);
+	for (j = 0; j < N; j++) {
+		fprintf(stdout,"cp[%d] = %e, expect %e\n",j,cp[j],expect[j]);
+	}
+
+	return 0;
+} /* main() */
+
+/* Function being minimized */
+double fcn(		/* Return function value */
+void *fdata,		/* Opaque data pointer */
+double tp[]			/* Multivriate input value */
+) {
+	double err, tt;
+	double temp, temp1, temp2;
+	int k;
+
+	/* Function Body */
+	err = 0.0;
+	for (k = 0; k < N; ++k) {
+		temp = (3.0 - 2.0 * tp[k]) * tp[k];
+		temp1 = 0.0;
+		if (k != 0) {
+			temp1 = tp[k-1];
+		}
+		temp2 = 0.0;
+		if (k != ((N)-1))
+			temp2 = tp[k+1];
+		tt = temp - temp1 - 2.0 * temp2 + 1.0;
+		err += tt * tt;
+	}
+	err = sqrt(err);
+// printf("Returning %16.14f\n",err);
+	return err;
+}
+
+
+
+
+
+
+
+
+
+
+
+