MAINT: rework result_type_impl to accept *tensors, not dtypes

torch_np/_binary_ufuncs_impl.py

@@ -51,7 +51,7 @@ def matmul(x, y):
     #  - RuntimeError: expected scalar type Int but found Double
     #  - RuntimeError: "addmm_impl_cpu_" not implemented for 'Bool'
     #  - RuntimeError: "addmm_impl_cpu_" not implemented for 'Half'
-    dtype = _dtypes_impl.result_type_impl((x.dtype, y.dtype))
+    dtype = _dtypes_impl.result_type_impl(x, y)
     is_bool = dtype == torch.bool
     is_half = dtype == torch.float16
 

torch_np/_dtypes.py

@@ -6,7 +6,7 @@
 
 import torch
 
-from . import _dtypes_impl
+from . import _dtypes_impl, _util
 
 # more __all__ manipulations at the bottom
 __all__ = ["dtype", "DType", "typecodes", "issubdtype", "set_default_dtype"]
@@ -34,7 +34,7 @@ def __new__(self, value):
             tensor = value.tensor
         else:
             try:
-                tensor = torch.as_tensor(value, dtype=self.torch_dtype)
+                tensor = _util._coerce_to_tensor(value, dtype=self.torch_dtype)
             except RuntimeError as e:
                 if "Overflow" in str(e):
                     raise OverflowError(e.args)

torch_np/_dtypes_impl.py

@@ -39,13 +39,13 @@ def can_cast_impl(from_torch_dtype, to_torch_dtype, casting):
     return _cd._can_cast_dict[casting][from_torch_dtype][to_torch_dtype]
 
 
-def result_type_impl(dtypes):
+def result_type_impl(*tensors):
     # NB: torch dtypes here
-    dtyp = dtypes[0]
-    if len(dtypes) == 1:
+    dtyp = tensors[0].dtype
+    if len(tensors) == 1:
         return dtyp
 
-    for curr in dtypes[1:]:
-        dtyp = _cd._result_type_dict[dtyp][curr]
+    for curr in tensors[1:]:
+        dtyp = _cd._result_type_dict[dtyp][curr.dtype]
 
     return dtyp

torch_np/_funcs_impl.py

@@ -91,7 +91,7 @@ def _concat_cast_helper(tensors, out=None, dtype=None, casting="same_kind"):
         # figure out the type of the inputs and outputs
         out_dtype = out.dtype.torch_dtype if dtype is None else dtype
     else:
-        out_dtype = _dtypes_impl.result_type_impl([t.dtype for t in tensors])
+        out_dtype = _dtypes_impl.result_type_impl(*tensors)
 
     # cast input arrays if necessary; do not broadcast them agains `out`
     tensors = _util.typecast_tensors(tensors, out_dtype, casting)
@@ -354,9 +354,11 @@ def arange(
     # the dtype of the result
     if dtype is None:
         dtype = _dtypes_impl.default_dtypes.int_dtype
-    dt_list = [_util._coerce_to_tensor(x).dtype for x in (start, stop, step)]
-    dt_list.append(dtype)
-    target_dtype = _dtypes_impl.result_type_impl(dt_list)
+    # XXX: default values do not get normalized
+    start, stop, step = (_util._coerce_to_tensor(x) for x in (start, stop, step))
+
+    dummy = torch.empty(1, dtype=dtype)
+    target_dtype = _dtypes_impl.result_type_impl(start, stop, step, dummy)
 
     # work around RuntimeError: "arange_cpu" not implemented for 'ComplexFloat'
     work_dtype = torch.float64 if target_dtype.is_complex else target_dtype
@@ -571,7 +573,7 @@ def cov(
 
 
 def _conv_corr_impl(a, v, mode):
-    dt = _dtypes_impl.result_type_impl((a.dtype, v.dtype))
+    dt = _dtypes_impl.result_type_impl(a, v)
     a = _util.cast_if_needed(a, dt)
     v = _util.cast_if_needed(v, dt)
 
@@ -857,15 +859,14 @@ def nanpercentile():
 
 
 def isclose(a: ArrayLike, b: ArrayLike, rtol=1.0e-5, atol=1.0e-8, equal_nan=False):
-    dtype = _dtypes_impl.result_type_impl((a.dtype, b.dtype))
+    dtype = _dtypes_impl.result_type_impl(a, b)
     a = _util.cast_if_needed(a, dtype)
     b = _util.cast_if_needed(b, dtype)
-    result = torch.isclose(a, b, rtol=rtol, atol=atol, equal_nan=equal_nan)
-    return result
+    return torch.isclose(a, b, rtol=rtol, atol=atol, equal_nan=equal_nan)
 
 
 def allclose(a: ArrayLike, b: ArrayLike, rtol=1e-05, atol=1e-08, equal_nan=False):
-    dtype = _dtypes_impl.result_type_impl((a.dtype, b.dtype))
+    dtype = _dtypes_impl.result_type_impl(a, b)
     a = _util.cast_if_needed(a, dtype)
     b = _util.cast_if_needed(b, dtype)
     return torch.allclose(a, b, rtol=rtol, atol=atol, equal_nan=equal_nan)
@@ -1175,7 +1176,7 @@ def vdot(a: ArrayLike, b: ArrayLike, /):
     if t_b.ndim > 1:
         t_b = t_b.flatten()
 
-    dtype = _dtypes_impl.result_type_impl((t_a.dtype, t_b.dtype))
+    dtype = _dtypes_impl.result_type_impl(t_a, t_b)
     is_half = dtype == torch.float16
     is_bool = dtype == torch.bool
 
@@ -1202,15 +1203,15 @@ def tensordot(a: ArrayLike, b: ArrayLike, axes=2):
     if isinstance(axes, (list, tuple)):
         axes = [[ax] if isinstance(ax, int) else ax for ax in axes]
 
-    target_dtype = _dtypes_impl.result_type_impl((a.dtype, b.dtype))
+    target_dtype = _dtypes_impl.result_type_impl(a, b)
     a = _util.cast_if_needed(a, target_dtype)
     b = _util.cast_if_needed(b, target_dtype)
 
     return torch.tensordot(a, b, dims=axes)
 
 
 def dot(a: ArrayLike, b: ArrayLike, out: Optional[OutArray] = None):
-    dtype = _dtypes_impl.result_type_impl((a.dtype, b.dtype))
+    dtype = _dtypes_impl.result_type_impl(a, b)
     a = _util.cast_if_needed(a, dtype)
     b = _util.cast_if_needed(b, dtype)
 
@@ -1222,7 +1223,7 @@ def dot(a: ArrayLike, b: ArrayLike, out: Optional[OutArray] = None):
 
 
 def inner(a: ArrayLike, b: ArrayLike, /):
-    dtype = _dtypes_impl.result_type_impl((a.dtype, b.dtype))
+    dtype = _dtypes_impl.result_type_impl(a, b)
     is_half = dtype == torch.float16
     is_bool = dtype == torch.bool
 
@@ -1284,11 +1285,7 @@ def einsum(*operands, out=None, dtype=None, order="K", casting="safe", optimize=
         subscripts, array_operands = operands[0], operands[1:]
 
     tensors = [normalize_array_like(op) for op in array_operands]
-    target_dtype = (
-        _dtypes_impl.result_type_impl([op.dtype for op in tensors])
-        if dtype is None
-        else dtype
-    )
+    target_dtype = _dtypes_impl.result_type_impl(*tensors) if dtype is None else dtype
 
     # work around 'bmm' not implemented for 'Half' etc
     is_half = target_dtype == torch.float16

torch_np/_ndarray.py

@@ -518,11 +518,14 @@ def can_cast(from_, to, casting="safe"):
 
 
 def result_type(*arrays_and_dtypes):
-    dtypes = []
-
+    tensors = []
     for entry in arrays_and_dtypes:
-        dty = _extract_dtype(entry)
-        dtypes.append(dty.torch_dtype)
+        try:
+            t = asarray(entry).tensor
+        except ((RuntimeError, ValueError, TypeError)):
+            dty = _dtypes.dtype(entry)
+            t = torch.empty(1, dtype=dty.torch_dtype)
+        tensors.append(t)
 
-    torch_dtype = _dtypes_impl.result_type_impl(dtypes)
+    torch_dtype = _dtypes_impl.result_type_impl(*tensors)
     return _dtypes.dtype(torch_dtype)

torch_np/_reductions.py

@@ -342,7 +342,7 @@ def average(
             weights = weights.swapaxes(-1, axis)
 
         # do the work
-        result_dtype = _dtypes_impl.result_type_impl([a.dtype, weights.dtype])
+        result_dtype = _dtypes_impl.result_type_impl(a, weights)
         numerator = sum(a * weights, axis, dtype=result_dtype)
         wsum = sum(weights, axis, dtype=result_dtype)
         result = numerator / wsum

torch_np/_ufuncs.py

@@ -17,7 +17,7 @@
 
 def _ufunc_preprocess(tensors, where, casting, order, dtype, subok, signature, extobj):
     if dtype is None:
-        dtype = _dtypes_impl.result_type_impl([t.dtype for t in tensors])
+        dtype = _dtypes_impl.result_type_impl(*tensors)
 
     tensors = _util.typecast_tensors(tensors, dtype, casting)
 
@@ -26,7 +26,7 @@ def _ufunc_preprocess(tensors, where, casting, order, dtype, subok, signature, e
 
 def _ufunc_postprocess(result, out, casting):
     if out is not None:
-        (result,) = _util.typecast_tensors((result,), out.dtype.torch_dtype, casting)
+        result = _util.typecast_tensor(result, out.dtype.torch_dtype, casting)
         result = torch.broadcast_to(result, out.shape)
     return result
 
@@ -198,10 +198,9 @@ def wrapped(
         signature=None,
         extobj=None,
     ):
-        tensors = _ufunc_preprocess(
-            (x,), where, casting, order, dtype, subok, signature, extobj
-        )
-        result = torch_func(*tensors)
+        if dtype is not None:
+            x = _util.typecast_tensor(x, dtype, casting)
+        result = torch_func(x)
         result = _ufunc_postprocess(result, out, casting)
         return result
 

torch_np/_util.py

@@ -135,37 +135,40 @@ def axis_none_flatten(*tensors, axis=None):
         return tensors, axis
 
 
-def typecast_tensors(tensors, target_dtype, casting):
-    """Dtype-cast tensors to target_dtype.
+def typecast_tensor(t, target_dtype, casting):
+    """Dtype-cast tensor to target_dtype.
 
     Parameters
     ----------
-    tensors : iterable
-            tuple or list of torch.Tensors to typecast
-    target_dtype : torch dtype object, optional
+    t : torch.Tensor
+        The tensor to cast
+    target_dtype : torch dtype object
         The array dtype to cast all tensors to
     casting : str
         The casting mode, see `np.can_cast`
 
-    Returns
-    -------
-    a tuple of torch.Tensors with dtype being the PyTorch counterpart
-    of the `target_dtype`
+     Returns
+     -------
+    `torch.Tensor` of the `target_dtype` dtype
+
+     Raises
+     ------
+     ValueError
+        if the argument cannot be cast according to the `casting` rule
+
     """
-    # check if we can dtype-cast all arguments
-    cast_tensors = []
     can_cast = _dtypes_impl.can_cast_impl
 
-    for tensor in tensors:
-        if not can_cast(tensor.dtype, target_dtype, casting=casting):
-            raise TypeError(
-                f"Cannot cast array data from {tensor.dtype} to"
-                f" {target_dtype} according to the rule '{casting}'"
-            )
-        tensor = cast_if_needed(tensor, target_dtype)
-        cast_tensors.append(tensor)
+    if not can_cast(t.dtype, target_dtype, casting=casting):
+        raise TypeError(
+            f"Cannot cast array data from {t.dtype} to"
+            f" {target_dtype} according to the rule '{casting}'"
+        )
+    return cast_if_needed(t, target_dtype)
+
 
-    return tuple(cast_tensors)
+def typecast_tensors(tensors, target_dtype, casting):
+    return tuple(typecast_tensor(t, target_dtype, casting) for t in tensors)
 
 
 def _coerce_to_tensor(obj, dtype=None, copy=False, ndmin=0):
@@ -193,7 +196,6 @@ def _coerce_to_tensor(obj, dtype=None, copy=False, ndmin=0):
     """
     if isinstance(obj, torch.Tensor):
         tensor = obj
-        base = None
     else:
         tensor = torch.as_tensor(obj)
         base = None

torch_np/linalg.py

@@ -21,7 +21,7 @@ def _atleast_float_1(a):
 
 
 def _atleast_float_2(a, b):
-    dtyp = _dtypes_impl.result_type_impl((a.dtype, b.dtype))
+    dtyp = _dtypes_impl.result_type_impl(a, b)
     if not (dtyp.is_floating_point or dtyp.is_complex):
         dtyp = _dtypes_impl.default_dtypes.float_dtype