add is_*_namespace helper functions

closes gh-156

array_api_compat/common/_helpers.py

@@ -202,7 +202,6 @@ def is_jax_array(x):
 
     return isinstance(x, jax.Array) or _is_jax_zero_gradient_array(x)
 
-
 def is_pydata_sparse_array(x) -> bool:
     """
     Return True if `x` is an array from the `sparse` package.
@@ -255,6 +254,166 @@ def is_array_api_obj(x):
         or is_pydata_sparse_array(x) \
         or hasattr(x, '__array_namespace__')
 
+def _compat_module_name():
+    assert __name__.endswith('.common._helpers')
+    return __name__.removesuffix('.common._helpers')
+
+def is_numpy_namespace(xp) -> bool:
+    """
+    Returns True if `xp` is a NumPy namespace.
+
+    This includes both NumPy itself and the version wrapped by array-api-compat.
+
+    See Also
+    --------
+
+    array_namespace
+    is_cupy_namespace
+    is_torch_namespace
+    is_ndonnx_namespace
+    is_dask_namespace
+    is_jax_namespace
+    is_pydata_sparse_namespace
+    is_array_api_strict_namespace
+    """
+    return xp.__name__ in {'numpy', _compat_module_name + '.numpy'}
+
+def is_cupy_namespace(xp) -> bool:
+    """
+    Returns True if `xp` is a CuPy namespace.
+
+    This includes both CuPy itself and the version wrapped by array-api-compat.
+
+    See Also
+    --------
+
+    array_namespace
+    is_numpy_namespace
+    is_torch_namespace
+    is_ndonnx_namespace
+    is_dask_namespace
+    is_jax_namespace
+    is_pydata_sparse_namespace
+    is_array_api_strict_namespace
+    """
+    return xp.__name__ in {'cupy', _compat_module_name + '.cupy'}
+
+def is_torch_namespace(xp) -> bool:
+    """
+    Returns True if `xp` is a PyTorch namespace.
+
+    This includes both PyTorch itself and the version wrapped by array-api-compat.
+
+    See Also
+    --------
+
+    array_namespace
+    is_numpy_namespace
+    is_cupy_namespace
+    is_ndonnx_namespace
+    is_dask_namespace
+    is_jax_namespace
+    is_pydata_sparse_namespace
+    is_array_api_strict_namespace
+    """
+    return xp.__name__ in {'torch', _compat_module_name + '.torch'}
+
+
+def is_ndonnx_namespace(xp):
+    """
+    Returns True if `xp` is an NDONNX namespace.
+
+    See Also
+    --------
+
+    array_namespace
+    is_numpy_namespace
+    is_cupy_namespace
+    is_torch_namespace
+    is_dask_namespace
+    is_jax_namespace
+    is_pydata_sparse_namespace
+    is_array_api_strict_namespace
+    """
+    return xp.__name__ == 'ndonnx'
+
+def is_dask_namespace(xp):
+    """
+    Returns True if `xp` is a Dask namespace.
+
+    This includes both ``dask.array`` itself and the version wrapped by array-api-compat.
+
+    See Also
+    --------
+
+    array_namespace
+    is_numpy_namespace
+    is_cupy_namespace
+    is_torch_namespace
+    is_ndonnx_namespace
+    is_jax_namespace
+    is_pydata_sparse_namespace
+    is_array_api_strict_namespace
+    """
+    return xp.__name__ in {'dask.array', _compat_module_name + '.dask.array'}
+
+def is_jax_namespace(xp):
+    """
+    Returns True if `xp` is a JAX namespace.
+
+    This includes ``jax.numpy`` and ``jax.experimental.array_api`` which existed in
+    older versions of JAX.
+
+    See Also
+    --------
+
+    array_namespace
+    is_numpy_namespace
+    is_cupy_namespace
+    is_torch_namespace
+    is_ndonnx_namespace
+    is_dask_namespace
+    is_pydata_sparse_namespace
+    is_array_api_strict_namespace
+    """
+    return xp.__name__ in {'jax.numpy', 'jax.experimental.array_api'}
+
+def is_pydata_sparse_namespace(xp):
+    """
+    Returns True if `xp` is a pydata/sparse namespace.
+
+    See Also
+    --------
+
+    array_namespace
+    is_numpy_namespace
+    is_cupy_namespace
+    is_torch_namespace
+    is_ndonnx_namespace
+    is_dask_namespace
+    is_jax_namespace
+    is_array_api_strict_namespace
+    """
+    return xp.__name__ == 'sparse'
+
+def is_array_api_strict_namespace(xp):
+    """
+    Returns True if `xp` is an array-api-strict namespace.
+
+    See Also
+    --------
+
+    array_namespace
+    is_numpy_namespace
+    is_cupy_namespace
+    is_torch_namespace
+    is_ndonnx_namespace
+    is_dask_namespace
+    is_jax_namespace
+    is_pydata_sparse_namespace
+    """
+    return xp.__name__ == 'array_api_strict'
+
 def _check_api_version(api_version):
     if api_version == '2021.12':
         warnings.warn("The 2021.12 version of the array API specification was requested but the returned namespace is actually version 2022.12")
@@ -643,13 +802,21 @@ def size(x):
     "device",
     "get_namespace",
     "is_array_api_obj",
+    "is_array_api_strict_namespace",
     "is_cupy_array",
+    "is_cupy_namespace",
     "is_dask_array",
+    "is_dask_namespace",
     "is_jax_array",
+    "is_jax_namespace",
     "is_numpy_array",
+    "is_numpy_namespace",
     "is_torch_array",
+    "is_torch_namespace",
     "is_ndonnx_array",
+    "is_ndonnx_namespace",
     "is_pydata_sparse_array",
+    "is_pydata_sparse_namespace",
     "size",
     "to_device",
 ]