1 files changed, 37 insertions, 0 deletions
diff --git a/gsl-1.9/doc/examples/integration.c b/gsl-1.9/doc/examples/integration.c
new file mode 100644
index 0000000..a8f2450
--- /dev/null
+++ b/gsl-1.9/doc/examples/integration.c
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <math.h>
+#include <gsl/gsl_integration.h>
+
+double f (double x, void * params) {
+  double alpha = *(double *) params;
+  double f = log(alpha*x) / sqrt(x);
+  return f;
+}
+
+int
+main (void)
+{
+  gsl_integration_workspace * w 
+    = gsl_integration_workspace_alloc (1000);
+  
+  double result, error;
+  double expected = -4.0;
+  double alpha = 1.0;
+
+  gsl_function F;
+  F.function = &f;
+  F.params = &alpha;
+
+  gsl_integration_qags (&F, 0, 1, 0, 1e-7, 1000,
+                        w, &result, &error); 
+
+  printf ("result          = % .18f\n", result);
+  printf ("exact result    = % .18f\n", expected);
+  printf ("estimated error = % .18f\n", error);
+  printf ("actual error    = % .18f\n", result - expected);
+  printf ("intervals =  %d\n", w->size);
+
+  gsl_integration_workspace_free (w);
+
+  return 0;
+}