define 0^0 as (1,+0), since the sign of the imaginary part cannot be determined

git-svn-id: svn://scm.gforge.inria.fr/svn/mpc/trunk@1121 211d60ee-9f03-0410-a15a-8952a2c7a4e4

1 files changed, 4 insertions, 28 deletions

diff --git a/src/pow.c b/src/pow.c
index f6d54a8..3c4e8dc 100644
--- a/src/pow.c
+++ b/src/pow.c
@@ -1,6 +1,6 @@
 /* mpc_pow -- Raise a complex number to the power of another complex number.
 
-Copyright (C) 2009, 2010, 2011 INRIA
+Copyright (C) 2009, 2010, 2011, 2012 INRIA
 
 This file is part of GNU MPC.
 
@@ -491,34 +491,10 @@ mpc_pow (mpc_ptr z, mpc_srcptr x, mpc_srcptr y, mpc_rnd_t rnd)
     {
       if (x_real && mpfr_zero_p (mpc_realref(x)))
         {
-          /* we define 0^0 to be (1, -sign(Im(y))*0) since the real part is
+          /* we define 0^0 to be (1, +0) since the real part is
              coherent with MPFR where 0^0 gives 1, and the sign of the
-             imaginary part is the most frequent one obtained for random
-             tiny x and y, for example with the following Sage program:
-             D = dict()
-             for sa in [-1,1]:
-               for sb in [-1,1]:
-                 for sc in [-1,1]:
-                   for sd in [-1,1]:
-                     D[(sa,sb,sc,sd)] = [0,0]
-             def tiny():
-               return (random() - 0.5) * 1e-3
-             for n in range(10^4):
-               a = tiny()
-               b = tiny()
-               c = tiny()
-               d = tiny()
-               x = a+I*b
-               y = c+I*d
-               z = x^y
-               t = sign(a),sign(b),sign(c),sign(d)
-               if sign(z.imag()) == 1:
-                 D[t] = [D[t][0],D[t][1]+1]
-               else:
-                 D[t] = [D[t][0]+1,D[t][1]] */
-          mpfr_set_ui (mpc_realref(z), 1, GMP_RNDZ);
-          mpfr_set_zero (mpc_imagref(z),
-                         mpfr_signbit (mpc_imagref(y)) ? 1 : -1);
+             imaginary part cannot be determined                       */
+          mpc_set_ui_ui (z, 1, 0, MPC_RNDNN);
           return 0;
         }
       else /* x^0 = 1 +/- i*0 even for x=NaN see algorithms.tex for the