1 files changed, 58 insertions, 0 deletions
diff --git a/gsl-1.9/doc/examples/roots.c b/gsl-1.9/doc/examples/roots.c
new file mode 100644
index 0000000..7854fbc
--- /dev/null
+++ b/gsl-1.9/doc/examples/roots.c
@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <gsl/gsl_errno.h>
+#include <gsl/gsl_math.h>
+#include <gsl/gsl_roots.h>
+
+#include "demo_fn.h"
+#include "demo_fn.c"
+
+int
+main (void)
+{
+  int status;
+  int iter = 0, max_iter = 100;
+  const gsl_root_fsolver_type *T;
+  gsl_root_fsolver *s;
+  double r = 0, r_expected = sqrt (5.0);
+  double x_lo = 0.0, x_hi = 5.0;
+  gsl_function F;
+  struct quadratic_params params = {1.0, 0.0, -5.0};
+
+  F.function = &quadratic;
+  F.params = &params;
+
+  T = gsl_root_fsolver_brent;
+  s = gsl_root_fsolver_alloc (T);
+  gsl_root_fsolver_set (s, &F, x_lo, x_hi);
+
+  printf ("using %s method\n", 
+          gsl_root_fsolver_name (s));
+
+  printf ("%5s [%9s, %9s] %9s %10s %9s\n",
+          "iter", "lower", "upper", "root", 
+          "err", "err(est)");
+
+  do
+    {
+      iter++;
+      status = gsl_root_fsolver_iterate (s);
+      r = gsl_root_fsolver_root (s);
+      x_lo = gsl_root_fsolver_x_lower (s);
+      x_hi = gsl_root_fsolver_x_upper (s);
+      status = gsl_root_test_interval (x_lo, x_hi,
+                                       0, 0.001);
+
+      if (status == GSL_SUCCESS)
+        printf ("Converged:\n");
+
+      printf ("%5d [%.7f, %.7f] %.7f %+.7f %.7f\n",
+              iter, x_lo, x_hi,
+              r, r - r_expected, 
+              x_hi - x_lo);
+    }
+  while (status == GSL_CONTINUE && iter < max_iter);
+
+  gsl_root_fsolver_free (s);
+
+  return status;
+}