update dpnp.fix docstring

Author: Vahid Tavanashad

dpnp/dpnp_iface_mathematical.py

@@ -1750,8 +1750,8 @@ def ediff1d(ary, to_end=None, to_begin=None):
 -------
 out : dpnp.ndarray
     An array with the rounded values and with the same dimensions as the input.
-    The returned array will have the default floating point data type for the
-    device where `a` is allocated.
+    The returned array will have a floating point data type that input can cast
+    to it safely considering device capabilities.
     If `out` is ``None`` then a float array is returned with the rounded values.
     Otherwise the result is stored there and the return value `out` is
     a reference to that array.

dpnp/dpnp_iface_statistics.py

@@ -797,8 +797,8 @@ def cov(
         Default: ``None``.
     dtype : {None, str, dtype object}, optional
         Data-type of the result. By default, the return data-type will have
-        at least floating point type based on the capabilities of the device on
-        which the input arrays reside.
+        the default floating point data-type of the device on which the input
+        arrays reside.
 
         Default: ``None``.
 

dpnp/tests/test_mathematical.py

@@ -36,30 +36,6 @@
 from .third_party.cupy import testing
 
 
-def _get_output_data_type(dtype):
-    """Return a data type specified by input `dtype` and device capabilities."""
-    dtype_float16 = any(
-        dpnp.issubdtype(dtype, t) for t in (dpnp.bool, dpnp.int8, dpnp.uint8)
-    )
-    dtype_float32 = any(
-        dpnp.issubdtype(dtype, t) for t in (dpnp.int16, dpnp.uint16)
-    )
-    if dtype_float16:
-        out_dtype = dpnp.float16 if has_support_aspect16() else dpnp.float32
-    elif dtype_float32:
-        out_dtype = dpnp.float32
-    elif dpnp.issubdtype(dtype, dpnp.complexfloating):
-        out_dtype = dpnp.complex64
-        if has_support_aspect64() and dtype != dpnp.complex64:
-            out_dtype = dpnp.complex128
-    else:
-        out_dtype = dpnp.float32
-        if has_support_aspect64() and dtype != dpnp.float32:
-            out_dtype = dpnp.float64
-
-    return out_dtype
-
-
 @pytest.mark.parametrize("deg", [True, False])
 class TestAngle:
     def test_angle_bool(self, deg):
@@ -775,6 +751,16 @@ def test_errors(self):
 
 
 class TestFix:
+    def get_output_data_type(self, dtype, device):
+        if dpnp.can_cast(dtype, dpnp.float16):
+            return dpnp.float16
+        if dpnp.can_cast(dtype, dpnp.float32):
+            return dpnp.float32
+        if dpnp.can_cast(dtype, dpnp.float64):
+            return dpnp.float64
+
+        return dpnp.default_float_type(device)
+
     @pytest.mark.parametrize(
         "dt", get_all_dtypes(no_none=True, no_complex=True)
     )
@@ -802,7 +788,9 @@ def test_out(self, a_dt):
         )
         ia = dpnp.array(a)
 
-        out_dt = _get_output_data_type(a.dtype)
+        # numpy output has the same dtype as input
+        # dpnp output always has a floating point dtype
+        out_dt = self.get_output_data_type(a.dtype, a.device)
         out = numpy.zeros_like(a, dtype=out_dt)
         iout = dpnp.array(out)