Merge pull request numpy#3187 from ericfode/float16pow

Float16pow

Author: certik

numpy/core/src/scalarmathmodule.c.src

@@ -494,16 +494,25 @@ half_ctype_remainder(npy_half a, npy_half b, npy_half *out) {
 /**end repeat**/
 
 /**begin repeat
- * #name = half, float, double, longdouble#
- * #type = npy_half, npy_float, npy_double, npy_longdouble#
+ * #name = float, double, longdouble#
+ * #type = npy_float, npy_double, npy_longdouble#
  */
 static npy_@name@ (*_basic_@name@_pow)(@type@ a, @type@ b);
 
 static void
-@name@_ctype_power(@type@ a, @type@ b, @type@ *out) {
+@name@_ctype_power(@type@ a, @type@ b, @type@ *out) 
+{
     *out = _basic_@name@_pow(a, b);
 }
 /**end repeat**/
+static void
+half_ctype_power(npy_half a, npy_half b, npy_half *out)
+{
+    const npy_float af = npy_half_to_float(a);
+    const npy_float bf = npy_half_to_float(b);
+    const npy_float outf = _basic_float_pow(af,bf);
+    *out = npy_float_to_half(outf);
+}
 
 /**begin repeat
  * #name = byte, ubyte, short, ushort, int, uint,
@@ -1130,7 +1139,6 @@ static PyObject *
     int first;
 
     @type@ out = @zero@;
-
     switch(_@name@_convert2_to_ctypes(a, &arg1, b, &arg2)) {
         case 0:
             break;
@@ -1724,7 +1732,6 @@ get_functions(void)
         i += 3;
         j++;
     }
-    _basic_half_pow = funcdata[j - 1];
     _basic_float_pow = funcdata[j];
     _basic_double_pow = funcdata[j + 1];
     _basic_longdouble_pow = funcdata[j + 2];

numpy/core/tests/test_scalarmath.py

@@ -44,7 +44,7 @@ def test_type_create(self, level=1):
 
 class TestPower(TestCase):
     def test_small_types(self):
-        for t in [np.int8, np.int16]:
+        for t in [np.int8, np.int16, np.float16]:
             a = t(3)
             b = a ** 4
             assert_(b == 81, "error with %r: got %r" % (t,b))
@@ -58,7 +58,21 @@ def test_large_types(self):
                 assert_(b == 6765201, msg)
             else:
                 assert_almost_equal(b, 6765201, err_msg=msg)
-
+    def test_mixed_types(self):
+        typelist = [np.int8,np.int16,np.float16,
+                    np.float32,np.float64,np.int8,
+                    np.int16,np.int32,np.int64]
+        for t1 in typelist:
+            for t2 in typelist:
+                a = t1(3)
+                b = t2(2)
+                result = a**b
+                msg = ("error with %r and %r:"
+                       "got %r, expected %r") % (t1, t2, result, 9)
+                if np.issubdtype(np.dtype(result), np.integer):
+                    assert_(result == 9, msg)
+                else:
+                    assert_almost_equal(result, 9, err_msg=msg)
 
 class TestComplexDivision(TestCase):
     def test_zero_division(self):