Group linalg API docs by category and pin them to __all__

The linalg.rst page used `.. automodule:: pytensor.tensor.linalg
:members:`, which renders all 36 functions from `__all__` as one
unstructured alphabetical list. Replace it with hand-grouped sections
(Constructors / Decomposition / Inverse / Products / Solve / Summary)
that mirror the internal `_linalg/` package layout, using explicit
`autofunction::` directives.

To stop the rst from drifting away from the public API, add
`tests/tensor/linalg/test_doc_api.py`. It parses every
`.. autofunction:: pytensor.tensor.linalg.<name>` directive out of the
rst and asserts the resulting set is exactly equal to
`pytensor.tensor.linalg.__all__`. Any future addition or removal on
either side fails the test with a precise diff.

Op classes remain undocumented in the rst — the public surface is
intentionally functions only.

Author: ricardoV94

doc/library/tensor/linalg.rst

@@ -8,9 +8,65 @@
    :platform: Unix, Windows
    :synopsis: Linear Algebra Operations
 
-API
-===
+The :mod:`pytensor.tensor.linalg` module exposes the user-facing linear
+algebra API.
 
-.. automodule:: pytensor.tensor.linalg
-    :members:
+Constructors
+============
 
+.. autofunction:: pytensor.tensor.linalg.block_diag
+
+Decomposition
+=============
+
+.. autofunction:: pytensor.tensor.linalg.cholesky
+.. autofunction:: pytensor.tensor.linalg.lu
+.. autofunction:: pytensor.tensor.linalg.lu_factor
+.. autofunction:: pytensor.tensor.linalg.pivot_to_permutation
+.. autofunction:: pytensor.tensor.linalg.qr
+.. autofunction:: pytensor.tensor.linalg.svd
+.. autofunction:: pytensor.tensor.linalg.eig
+.. autofunction:: pytensor.tensor.linalg.eigh
+.. autofunction:: pytensor.tensor.linalg.eigvalsh
+.. autofunction:: pytensor.tensor.linalg.schur
+.. autofunction:: pytensor.tensor.linalg.qz
+.. autofunction:: pytensor.tensor.linalg.ordqz
+
+Inverse
+=======
+
+.. autofunction:: pytensor.tensor.linalg.inv
+.. autofunction:: pytensor.tensor.linalg.pinv
+.. autofunction:: pytensor.tensor.linalg.tensorinv
+
+Products
+========
+
+.. autofunction:: pytensor.tensor.linalg.kron
+.. autofunction:: pytensor.tensor.linalg.matrix_dot
+.. autofunction:: pytensor.tensor.linalg.matrix_power
+.. autofunction:: pytensor.tensor.linalg.expm
+
+Solve
+=====
+
+.. autofunction:: pytensor.tensor.linalg.solve
+.. autofunction:: pytensor.tensor.linalg.solve_triangular
+.. autofunction:: pytensor.tensor.linalg.lu_solve
+.. autofunction:: pytensor.tensor.linalg.cho_solve
+.. autofunction:: pytensor.tensor.linalg.lstsq
+.. autofunction:: pytensor.tensor.linalg.tensorsolve
+.. autofunction:: pytensor.tensor.linalg.tridiagonal_lu_factor
+.. autofunction:: pytensor.tensor.linalg.tridiagonal_lu_solve
+.. autofunction:: pytensor.tensor.linalg.solve_continuous_lyapunov
+.. autofunction:: pytensor.tensor.linalg.solve_discrete_lyapunov
+.. autofunction:: pytensor.tensor.linalg.solve_discrete_are
+.. autofunction:: pytensor.tensor.linalg.solve_sylvester
+
+Summary
+=======
+
+.. autofunction:: pytensor.tensor.linalg.det
+.. autofunction:: pytensor.tensor.linalg.slogdet
+.. autofunction:: pytensor.tensor.linalg.norm
+.. autofunction:: pytensor.tensor.linalg.trace

tests/tensor/linalg/test_doc_api.py

@@ -0,0 +1,58 @@
+"""Guard against drift between `pytensor.tensor.linalg.__all__` and the
+`doc/library/tensor/linalg.rst` API page.
+
+Both sides have to be edited together: if you add a new function to
+`__all__`, this test will fail until you also document it in the rst,
+and vice-versa. The doc page is hand-grouped into logical sections
+(decomposition, solve, ...), which is why we don't generate it from
+`__all__` automatically — but we do want a hard guarantee that the two
+stay in sync.
+"""
+
+import re
+from pathlib import Path
+
+import pytensor.tensor.linalg as linalg
+
+
+DOC_PATH = (
+    Path(__file__).resolve().parents[3] / "doc" / "library" / "tensor" / "linalg.rst"
+)
+
+_AUTOFUNCTION_RE = re.compile(
+    r"^\.\.\s+autofunction::\s+pytensor\.tensor\.linalg\.(\w+)\s*$",
+    re.MULTILINE,
+)
+
+
+def _documented_names() -> set[str]:
+    return set(_AUTOFUNCTION_RE.findall(DOC_PATH.read_text()))
+
+
+def test_linalg_doc_matches_all():
+    documented = _documented_names()
+    exported = set(linalg.__all__)
+
+    missing_from_docs = exported - documented
+    missing_from_all = documented - exported
+
+    assert not missing_from_docs, (
+        f"{len(missing_from_docs)} name(s) in pytensor.tensor.linalg.__all__ "
+        f"are not documented in {DOC_PATH.name}: {sorted(missing_from_docs)}. "
+        "Add an `.. autofunction::` entry to the appropriate section."
+    )
+    assert not missing_from_all, (
+        f"{len(missing_from_all)} name(s) documented in {DOC_PATH.name} "
+        f"are not in pytensor.tensor.linalg.__all__: {sorted(missing_from_all)}. "
+        "Either add them to `__all__` or remove the rst entry."
+    )
+
+
+def test_linalg_doc_has_no_duplicate_entries():
+    text = DOC_PATH.read_text()
+    documented = _AUTOFUNCTION_RE.findall(text)
+    duplicates = {name for name in documented if documented.count(name) > 1}
+    assert not duplicates, (
+        f"Duplicate `.. autofunction::` entries in {DOC_PATH.name}: "
+        f"{sorted(duplicates)}"
+    )