Use intersphinx instead of links to other docs' URLs

Author: asmeurer

Diff for: array_api_compat/common/_helpers.py

@@ -448,13 +448,11 @@ def to_device(x: Array, device: Device, /, *, stream: Optional[Union[int, Any]]
     -----
 
     For NumPy, this function effectively does nothing since the only supported
-    device is the CPU. For CuPy, this method supports CuPy CUDA `Device
-    <https://docs.cupy.dev/en/stable/reference/generated/cupy.cuda.Device.html>`_
-    and `Stream
-    <https://docs.cupy.dev/en/stable/reference/generated/cupy.cuda.Stream.html>`_
-    objects. For PyTorch, this is the same as `x.to(device)
-    <https://pytorch.org/docs/stable/generated/torch.Tensor.to.html>`_ (the
-    ``stream`` argument is not supported in PyTorch).
+    device is the CPU. For CuPy, this method supports CuPy CUDA
+    :external+cupy:class:`Device <cupy.cuda.Device>` and
+    :external+cupy:class:`Stream <cupy.cuda.Stream>` objects. For PyTorch,
+    this is the same as :external+torch:meth:`x.to(device) <torch.Tensor.to>`
+    (the ``stream`` argument is not supported in PyTorch).
 
     See Also
     --------
@@ -492,8 +490,8 @@ def size(x):
 
     This is equivalent to `x.size` according to the `standard
     <https://data-apis.org/array-api/latest/API_specification/generated/array_api.array.size.html>`__.
-    This helper is included because PyTorch defines `size` in an `incompatible
-    way <https://pytorch.org/docs/stable/generated/torch.Tensor.size.html>`__.
+    This helper is included because PyTorch defines `size` in an
+    :external+torch:meth:`incompatible way <torch.Tensor.size>`.
 
     """
     if None in x.shape:

Diff for: docs/conf.py

@@ -24,9 +24,17 @@
     'myst_parser',
     'sphinx.ext.autodoc',
     'sphinx.ext.napoleon',
+    'sphinx.ext.intersphinx',
     'sphinx_copybutton',
 ]
 
+intersphinx_mapping = {
+    'cupy': ('https://docs.cupy.dev/en/stable', None),
+    'torch': ('https://pytorch.org/docs/stable/', None),
+}
+# Require :external: to reference intersphinx.
+intersphinx_disabled_reftypes = ['*']
+
 templates_path = ['_templates']
 exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']