From f388aa73d9230b16388f39b6c56f2dc79193872b Mon Sep 17 00:00:00 2001
From: Chris Laurel <claurel@gmail.com>
Date: Wed, 5 Sep 2001 21:34:19 +0000
Subject: [PATCH] Template-based root finding algorithms.

---
 src/solve.h | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 src/solve.h

diff --git a/src/solve.h b/src/solve.h
new file mode 100644
index 000000000..5b651a234
--- /dev/null
+++ b/src/solve.h
@@ -0,0 +1,36 @@
+// solve.h
+// 
+// Copyright (C) 2001, Chris Laurel <claurel@shatters.net>
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+
+#include <utility>
+
+
+// Solve a function using the bisection method.  Returns a pair
+// with the solution as the first element and the error as the second.
+template<class T, class F> std::pair<T, T> solve_bisection(F f,
+                                                           T lower, T upper,
+                                                           T err,
+                                                           int maxIter = 100)
+{
+    T x = 0.0;
+
+    for (int i = 0; i < maxIter; i++)
+    {
+        x = (lower + upper) * (T) 0.5;
+        if (upper - lower < 2 * err)
+            break;
+
+        T y = f(x);
+        if (y < 0)
+            lower = x;
+        else
+            upper = x;
+    }
+
+    return std::make_pair(x, (upper - lower) / 2);
+}