BUG: Fix up some corner cases in npy_cexp

ewmoore · ewmoore · commit 852cd10423a0 · 2014-02-26T18:11:27.000-05:00
The failing c99 annex G values for cexp were:
cexp(Inf, -0) == (NAN, -0)
cexp(Inf, Inf) == (+-Inf, NAN) + raises FE_INVALID

The first returned (NAN, 0) and the second was correct but failed to
raise the invalid floating-point exception.
diff --git a/numpy/core/src/npymath/npy_math_complex.c.src b/numpy/core/src/npymath/npy_math_complex.c.src
@@ -172,7 +172,7 @@ static NPY_INLINE @ctype@ cmuli@c@(@ctype@ a)
     } else  if (npy_isnan(r)) {
         /* r is nan */
         if (i == 0) {
-            ret = npy_cpack@c@(r, 0);
+            ret = z;
         } else {
             ret = npy_cpack@c@(r, npy_copysign@c@(NPY_NAN, i));
         }
@@ -188,6 +188,7 @@ static NPY_INLINE @ctype@ cmuli@c@(@ctype@ a)
                 ret = npy_cpack@c@(r * c, r * s);
             } else {
                 /* x = +inf, y = +-inf | nan */
+                npy_set_floatstatus_invalid();
                 ret = npy_cpack@c@(r, NPY_NAN);
             }
         } else {
diff --git a/numpy/core/tests/test_umath_complex.py b/numpy/core/tests/test_umath_complex.py
@@ -123,6 +123,11 @@ def _check_inf_nan(dummy):
         # cexp(nan + nani) is nan + nani
         yield check, f, np.nan, np.nan, np.nan, np.nan
 
+        # cexp(nan +-0) is nan +-0
+        yield check, f, np.nan, np.PZERO, np.nan, np.PZERO, True
+        yield check, f, np.nan, np.NZERO, np.nan, np.NZERO, True
+
+
     @dec.knownfailureif(True, "cexp(nan + 0I) is wrong on most implementations")
     def test_special_values2(self):
         # XXX: most implementations get it wrong here (including glibc <= 2.10)
