BUG: core: handle sizeof(double) == sizeof(longdouble) in PyArray_CanCastSafely (fixes #1539)

Thanks to Christoph Gohlke for the patch.

2 files changed, 29 insertions, 1 deletions

diff --git a/numpy/core/src/multiarray/convert_datatype.c b/numpy/core/src/multiarray/convert_datatype.c
index ea43a4233..ca56b1e2e 100644
--- a/numpy/core/src/multiarray/convert_datatype.c
+++ b/numpy/core/src/multiarray/convert_datatype.c
@@ -634,13 +634,23 @@ PyArray_CanCastSafely(int fromtype, int totype)
         if (PyTypeNum_ISCOMPLEX(totype)) {
             return (telsize >> 1) >= felsize;
         }
+        else if (PyTypeNum_ISFLOAT(totype) && (telsize == felsize)) {
+            /* On some systems, double == longdouble */
+            return 1;
+        }
         else {
             return totype > fromtype;
         }
     case PyArray_CFLOAT:
     case PyArray_CDOUBLE:
     case PyArray_CLONGDOUBLE:
-        return totype > fromtype;
+        if (PyTypeNum_ISCOMPLEX(totype) && (telsize == felsize)) {
+            /* On some systems, double == longdouble */
+            return 1;
+        }
+        else {
+            return totype > fromtype;
+        }
     case PyArray_STRING:
     case PyArray_UNICODE:
         return totype > fromtype;
diff --git a/numpy/core/tests/test_regression.py b/numpy/core/tests/test_regression.py
index 9efebbac9..3dc1a653e 100644
--- a/numpy/core/tests/test_regression.py
+++ b/numpy/core/tests/test_regression.py
@@ -1302,5 +1302,23 @@ class TestRegression(TestCase):
         # Ticket #1345: the following should not cause a crash
         np.fromstring(asbytes('aa, aa, 1.0'), sep=',')
 
+    def test_issue1539(self):
+        dtypes = [x for x in np.typeDict.values()
+                  if (issubclass(x, np.number)
+                      and not issubclass(x, np.timeinteger))]
+        a = np.array([], dtypes[0])
+        failures = []
+        for x in dtypes:
+            b = a.astype(x)
+            for y in dtypes:
+                c = a.astype(y)
+                try:
+                    np.dot(b, c)
+                except TypeError, e:
+                    failures.append((x, y))
+        if failures:
+            raise AssertionError("Failures: %r" % failures)
+
+
 if __name__ == "__main__":
     run_module_suite()