src/proj.c: new fonction for projection onto the Riemann sphere.

src/mpc.h, src/Makefile.am, doc/mpc.texi: add mpc_proj.
tests/tproj.c, tests/proj.dat: Test files for function mpc_proj.
tests/Makefile.am: add mpc_proj test files.


git-svn-id: svn://scm.gforge.inria.fr/svn/mpc/trunk@290 211d60ee-9f03-0410-a15a-8952a2c7a4e4

1 files changed, 45 insertions, 0 deletions

diff --git a/src/proj.c b/src/proj.c
new file mode 100644
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--- /dev/null
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+/* mpc_proj -- projection of a complex number onto the Riemann sphere.
+
+Copyright (C) 2008 Philippe Th\'eveny
+
+This file is part of the MPC Library.
+
+The MPC 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 2.1 of the License, or (at your
+option) any later version.
+
+The MPC 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 MPC Library; see the file COPYING.LIB.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+#include "mpc.h"
+#include "mpc-impl.h"
+
+int
+mpc_proj (mpc_ptr a, mpc_srcptr b, mpc_rnd_t rnd)
+{
+  if (MPC_IS_INF (b))
+    {
+      /* infinities projects to +Inf +i* copysign(0.0, cimag(z)) */
+      int inex;
+
+      mpfr_set_inf (MPC_RE (a), +1);
+      inex = mpfr_set_ui (MPC_IM (a), 0, MPC_RND_IM (rnd));
+      if (mpfr_signbit (MPC_IM (b)))
+        {
+          mpc_conj (a, a, MPC_RNDNN);
+          inex = -inex;
+        }
+
+      return MPC_INEX (0, inex); 
+    } 
+  else
+    return mpc_set (a, b, rnd);
+}