add the function mpfr_dim

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@1344 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 90 insertions, 0 deletions

diff --git a/dim.c b/dim.c
new file mode 100644
index 000000000..ff4ad2e88
--- /dev/null
+++ b/dim.c
@@ -0,0 +1,90 @@
+/* mpfr_dim -- dim of x, y  
+
+Copyright (C) 2001 Free Software Foundation.
+
+This file is part of the MPFR Library.
+
+The MPFR Library 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.
+
+The 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 Library General Public
+License for more details.
+
+You should have received a copy of the GNU Library General Public License
+along with the MPFR 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 <stdio.h>
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "mpfr.h"
+#include "mpfr-impl.h"
+
+ /* The computation of z=dim(x,y)
+
+    x-y if x >  y
+    +0    if x <= y
+ */
+
+int
+#if __STDC__
+mpfr_dim (mpfr_ptr z, mpfr_srcptr x ,mpfr_srcptr y , mp_rnd_t rnd_mode) 
+#else
+mpfr_dim (z, x, y, rnd_mode)
+     mpfr_ptr z;
+     mpfr_srcptr x;
+     mpfr_srcptr y;
+     mp_rnd_t rnd_mode;
+#endif
+{
+    
+  /****** Declaration ******/
+
+    /* Variable of Intermediary Calculation*/
+    mpfr_t t;       
+
+    mp_prec_t Nx;   /* Precision of input variable */
+    mp_prec_t Nz;   /* Precision of input variable */
+    mp_prec_t Ny;   /* Precision of output variable */
+    mp_prec_t Nt;
+
+    int inexact=0;
+
+    if (MPFR_IS_NAN(x) || MPFR_IS_NAN(y) ) 
+    {  
+      MPFR_SET_NAN(z); 
+      return 1; 
+    }
+    MPFR_CLEAR_NAN(z);
+
+    /* Initialisation of the Precision */
+    Nx=MPFR_PREC(x);
+    Ny=MPFR_PREC(y);
+    Nz=MPFR_PREC(z);
+
+    /* compute the size of intermediary variable */
+    Nt=MAX(Nx,MAX(Ny,Nz));
+    
+    /* initialise of intermediary variable */
+    mpfr_init2(t,Nt);             
+
+    if(mpfr_cmp(x,y) > 0)
+      mpfr_sub(t,x,y,GMP_RNDN);
+    else
+    {
+      MPFR_SET_ZERO(t);
+      if(MPFR_SIGN(t) < 0) 
+        CHANGE_SIGN(t);
+    }
+
+    inexact = mpfr_set(z,t,rnd_mode);
+    
+    mpfr_clear(t);
+    return inexact;
+
+}