ENH: astype: add device kwarg (#240)

Co-authored-by: Lucas Colley <lucas.colley8@gmail.com>

Author: crusaderky

array_api_compat/common/_aliases.py

@@ -233,11 +233,6 @@ def unique_values(x: ndarray, /, xp) -> ndarray:
         **kwargs,
     )
 
-def astype(x: ndarray, dtype: Dtype, /, *, copy: bool = True) -> ndarray:
-    if not copy and dtype == x.dtype:
-        return x
-    return x.astype(dtype=dtype, copy=copy)
-
 # These functions have different keyword argument names
 
 def std(
@@ -549,7 +544,7 @@ def sign(x: ndarray, /, xp, **kwargs) -> ndarray:
            'linspace', 'ones', 'ones_like', 'zeros', 'zeros_like',
            'UniqueAllResult', 'UniqueCountsResult', 'UniqueInverseResult',
            'unique_all', 'unique_counts', 'unique_inverse', 'unique_values',
-           'astype', 'std', 'var', 'cumulative_sum', 'clip', 'permute_dims',
+           'std', 'var', 'cumulative_sum', 'clip', 'permute_dims',
            'reshape', 'argsort', 'sort', 'nonzero', 'ceil', 'floor', 'trunc',
            'matmul', 'matrix_transpose', 'tensordot', 'vecdot', 'isdtype',
            'unstack', 'sign']

array_api_compat/cupy/_aliases.py

@@ -2,7 +2,7 @@
 
 import cupy as cp
 
-from ..common import _aliases
+from ..common import _aliases, _helpers
 from .._internal import get_xp
 
 from ._info import __array_namespace_info__
@@ -46,7 +46,6 @@
 unique_counts = get_xp(cp)(_aliases.unique_counts)
 unique_inverse = get_xp(cp)(_aliases.unique_inverse)
 unique_values = get_xp(cp)(_aliases.unique_values)
-astype = _aliases.astype
 std = get_xp(cp)(_aliases.std)
 var = get_xp(cp)(_aliases.var)
 cumulative_sum = get_xp(cp)(_aliases.cumulative_sum)
@@ -110,6 +109,21 @@ def asarray(
 
         return cp.array(obj, dtype=dtype, **kwargs)
 
+
+def astype(
+    x: ndarray,
+    dtype: Dtype,
+    /,
+    *,
+    copy: bool = True,
+    device: Optional[Device] = None,
+) -> ndarray:
+    if device is None:
+        return x.astype(dtype=dtype, copy=copy)
+    out = _helpers.to_device(x.astype(dtype=dtype, copy=False), device)
+    return out.copy() if copy and out is x else out
+
+
 # These functions are completely new here. If the library already has them
 # (i.e., numpy 2.0), use the library version instead of our wrapper.
 if hasattr(cp, 'vecdot'):
@@ -127,10 +141,10 @@ def asarray(
 else:
     unstack = get_xp(cp)(_aliases.unstack)
 
-__all__ = _aliases.__all__ + ['__array_namespace_info__', 'asarray', 'bool',
+__all__ = _aliases.__all__ + ['__array_namespace_info__', 'asarray', 'astype',
                               'acos', 'acosh', 'asin', 'asinh', 'atan',
                               'atan2', 'atanh', 'bitwise_left_shift',
                               'bitwise_invert', 'bitwise_right_shift',
-                              'concat', 'pow', 'sign']
+                              'bool', 'concat', 'pow', 'sign']
 
 _all_ignore = ['cp', 'get_xp']

array_api_compat/dask/array/_aliases.py

@@ -233,7 +233,7 @@ def _isscalar(a):
 
 _common_aliases = [alias for alias in _aliases.__all__ if alias not in _da_unsupported]
 
-__all__ = _common_aliases + ['__array_namespace_info__', 'asarray', 'acos',
+__all__ = _common_aliases + ['__array_namespace_info__', 'asarray', 'astype', 'acos',
                     'acosh', 'asin', 'asinh', 'atan', 'atan2',
                     'atanh', 'bitwise_left_shift', 'bitwise_invert',
                     'bitwise_right_shift', 'concat', 'pow', 'iinfo', 'finfo', 'can_cast',

array_api_compat/numpy/_aliases.py

@@ -46,7 +46,6 @@
 unique_counts = get_xp(np)(_aliases.unique_counts)
 unique_inverse = get_xp(np)(_aliases.unique_inverse)
 unique_values = get_xp(np)(_aliases.unique_values)
-astype = _aliases.astype
 std = get_xp(np)(_aliases.std)
 var = get_xp(np)(_aliases.var)
 cumulative_sum = get_xp(np)(_aliases.cumulative_sum)
@@ -115,6 +114,18 @@ def asarray(
 
     return np.array(obj, copy=copy, dtype=dtype, **kwargs)
 
+
+def astype(
+    x: ndarray,
+    dtype: Dtype,
+    /,
+    *,
+    copy: bool = True,
+    device: Optional[Device] = None,
+) -> ndarray:
+    return x.astype(dtype=dtype, copy=copy)
+
+
 # These functions are completely new here. If the library already has them
 # (i.e., numpy 2.0), use the library version instead of our wrapper.
 if hasattr(np, 'vecdot'):
@@ -132,10 +143,10 @@ def asarray(
 else:
     unstack = get_xp(np)(_aliases.unstack)
 
-__all__ = _aliases.__all__ + ['__array_namespace_info__', 'asarray', 'bool',
+__all__ = _aliases.__all__ + ['__array_namespace_info__', 'asarray', 'astype',
                               'acos', 'acosh', 'asin', 'asinh', 'atan',
                               'atan2', 'atanh', 'bitwise_left_shift',
                               'bitwise_invert', 'bitwise_right_shift',
-                              'concat', 'pow']
+                              'bool', 'concat', 'pow']
 
 _all_ignore = ['np', 'get_xp']

array_api_compat/torch/_aliases.py

@@ -613,8 +613,19 @@ def triu(x: array, /, *, k: int = 0) -> array:
 def expand_dims(x: array, /, *, axis: int = 0) -> array:
     return torch.unsqueeze(x, axis)
 
-def astype(x: array, dtype: Dtype, /, *, copy: bool = True) -> array:
-    return x.to(dtype, copy=copy)
+
+def astype(
+    x: array,
+    dtype: Dtype,
+    /,
+    *,
+    copy: bool = True,
+    device: Optional[Device] = None,
+) -> array:
+    if device is not None:
+        return x.to(device, dtype=dtype, copy=copy)
+    return x.to(dtype=dtype, copy=copy)
+
 
 def broadcast_arrays(*arrays: array) -> List[array]:
     shape = torch.broadcast_shapes(*[a.shape for a in arrays])

cupy-xfails.txt

@@ -181,5 +181,4 @@ array_api_tests/test_fft.py::test_irfftn
 # cupy.ndaray cannot be specified as `repeats` argument.
 array_api_tests/test_manipulation_functions.py::test_repeat
 array_api_tests/test_signatures.py::test_func_signature[from_dlpack]
-array_api_tests/test_signatures.py::test_func_signature[astype]
 array_api_tests/test_signatures.py::test_array_method_signature[__dlpack__]

dask-xfails.txt

@@ -154,4 +154,3 @@ array_api_tests/test_statistical_functions.py::test_prod
 # 2023.12 support
 array_api_tests/test_manipulation_functions.py::test_repeat
 array_api_tests/test_searching_functions.py::test_searchsorted
-array_api_tests/test_signatures.py::test_func_signature[astype]

numpy-1-21-xfails.txt

@@ -254,7 +254,6 @@ array_api_tests/test_special_cases.py::test_iop[__iadd__(x1_i is -0 and x2_i is
 # 2023.12 support
 array_api_tests/test_searching_functions.py::test_searchsorted
 array_api_tests/test_signatures.py::test_func_signature[from_dlpack]
-array_api_tests/test_signatures.py::test_func_signature[astype]
 array_api_tests/test_signatures.py::test_array_method_signature[__dlpack__]
 # uint64 repeats not supported
 array_api_tests/test_manipulation_functions.py::test_repeat

numpy-1-26-xfails.txt

@@ -49,7 +49,6 @@ array_api_tests/test_statistical_functions.py::test_prod
 # 2023.12 support
 array_api_tests/test_searching_functions.py::test_searchsorted
 array_api_tests/test_signatures.py::test_func_signature[from_dlpack]
-array_api_tests/test_signatures.py::test_func_signature[astype]
 array_api_tests/test_signatures.py::test_array_method_signature[__dlpack__]
 # uint64 repeats not supported
 array_api_tests/test_manipulation_functions.py::test_repeat

numpy-dev-xfails.txt

@@ -20,7 +20,6 @@ array_api_tests/test_signatures.py::test_extension_func_signature[linalg.vecdot]
 
 # 2023.12 support
 # Argument 'device' missing from signature
-array_api_tests/test_signatures.py::test_func_signature[astype]
 array_api_tests/test_signatures.py::test_func_signature[from_dlpack]
 array_api_tests/test_signatures.py::test_array_method_signature[__dlpack__]
 # uint64 repeats not supported