1 files changed, 91 insertions, 0 deletions
diff --git a/examples/rndo-add.c b/examples/rndo-add.c
new file mode 100644
index 0000000..73b8a80
--- /dev/null
+++ b/examples/rndo-add.c
@@ -0,0 +1,91 @@
+/* This example was presented at the CNC'2 summer school on MPFR and MPC at
+ * LORIA, Nancy, France. It shows how one can use different rounding modes.
+ * This example implements the OddRoundedAdd algorithm, which returns the
+ * sum z = x + y rounded-to-odd:
+ *   * RO(z) = z if z is exactly representable;
+ *   * otherwise RO(z) is the value among RD(z) and RU(z) whose
+ *     least significant bit is a one.
+ */
+
+/*
+Copyright 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
+Contributed by the AriC and Caramel projects, INRIA.
+
+This file is part of the GNU MPFR Library.
+
+The GNU MPFR Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+The GNU MPFR Library 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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
+http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
+51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <gmp.h>
+#include <mpfr.h>
+
+#define LIST x, y, d, u, e, z
+
+int main (int argc, char **argv)
+{
+  mpfr_t LIST;
+  mpfr_prec_t prec;
+  int pprec;       /* will be prec - 1 for mpfr_printf */
+
+  if (argc != 4)
+    {
+      fprintf (stderr, "Usage: rndo-add <prec> <x> <y>\n");
+      exit (1);
+    }
+
+  prec = atoi (argv[1]);
+  if (prec < 2)
+    {
+      fprintf (stderr, "rndo-add: bad precision\n");
+      exit (1);
+    }
+  pprec = prec - 1;
+
+  mpfr_inits2 (prec, LIST, (mpfr_ptr) 0);
+
+  if (mpfr_set_str (x, argv[2], 0, MPFR_RNDN))
+    {
+      fprintf (stderr, "rndo-add: bad x value\n");
+      exit (1);
+    }
+  mpfr_printf ("x = %.*Rb\n", pprec, x);
+
+  if (mpfr_set_str (y, argv[3], 0, MPFR_RNDN))
+    {
+      fprintf (stderr, "rndo-add: bad y value\n");
+      exit (1);
+    }
+  mpfr_printf ("y = %.*Rb\n", pprec, y);
+
+  mpfr_add (d, x, y, MPFR_RNDD);
+  mpfr_printf ("d = %.*Rb\n", pprec, d);
+
+  mpfr_add (u, x, y, MPFR_RNDU);
+  mpfr_printf ("u = %.*Rb\n", pprec, u);
+
+  mpfr_add (e, d, u, MPFR_RNDN);
+  mpfr_div_2ui (e, e, 1, MPFR_RNDN);
+  mpfr_printf ("e = %.*Rb\n", pprec, e);
+
+  mpfr_sub (z, u, e, MPFR_RNDN);
+  mpfr_add (z, z, d, MPFR_RNDN);
+  mpfr_printf ("z = %.*Rb\n", pprec, z);
+
+  mpfr_clears (LIST, (mpfr_ptr) 0);
+  return 0;
+}