New function and example program computes Fibonacci numbers fairly fast.

[u/mdw/catacomb] / mp-fibonacci.h

diff --git a/mp-fibonacci.h b/mp-fibonacci.h
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+++ b/mp-fibonacci.h
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+/* -*-c-*-
+ *
+ * Compute the %$n$%th Fibonacci number
+ *
+ * (c) 2013 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * Catacomb is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with Catacomb; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#ifndef CATACOMB_MP_FIBONACCI_H
+#define CATACOMB_MP_FIBONACCI_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#ifndef CATACOMB_MP_H
+#  include "mp.h"
+#endif
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @mp_fibonacci@ --- *
+ *
+ * Arguments:  @long n@ = index desired (may be negative)
+ *
+ * Returns:    The %$n$%th Fibonacci number.
+ */
+
+extern mp *mp_fibonacci(long /*n*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif