Merge pull request #178 from ev-br/add_eig

ENH: add linalg.eig, linalg.eigvals if Array API vesion is at least 2025.12

Author: ev-br

array_api_strict/_linalg.py

@@ -9,7 +9,7 @@
 from ._data_type_functions import finfo
 from ._dtypes import DType, _floating_dtypes, _numeric_dtypes, complex64, complex128
 from ._elementwise_functions import conj
-from ._flags import get_array_api_strict_flags, requires_extension
+from ._flags import get_array_api_strict_flags, requires_extension, requires_api_version
 from ._manipulation_functions import reshape
 from ._statistical_functions import _np_dtype_sumprod
 
@@ -23,6 +23,10 @@ class EighResult(NamedTuple):
     eigenvalues: Array
     eigenvectors: Array
 
+class EigResult(NamedTuple):
+    eigenvalues: Array
+    eigenvectors: Array
+
 class QRResult(NamedTuple):
     Q: Array
     R: Array
@@ -144,6 +148,63 @@ def eigvalsh(x: Array, /) -> Array:
 
     return Array._new(np.linalg.eigvalsh(x._array), device=x.device)
 
+@requires_extension('linalg')
+@requires_api_version('2025.12')
+def eigvals(x: Array, /) -> Array:
+    """
+    Array API compatible wrapper for :py:func:`np.linalg.eigvals <numpy.linalg.eigvals>`.
+
+    See its docstring for more information.
+    """
+    # Note: the restriction to floating-point dtypes only is different from
+    # np.linalg.eigvals.
+    if x.dtype not in _floating_dtypes:
+        raise TypeError('Only floating-point dtypes are allowed in eigvals')
+
+    res = np.linalg.eigvals(x._array)
+
+    # numpy return reals for real inputs
+    res_dtype = res.dtype
+    if res.dtype == np.float32:
+        res_dtype = np.complex64
+    elif res.dtype == np.float64:
+        res_dtype = np.complex128
+
+    if res_dtype != res.dtype:
+        res = res.astype(res_dtype)
+
+    return Array._new(res, device=x.device)
+
+
+@requires_extension('linalg')
+@requires_api_version('2025.12')
+def eig(x: Array, /) -> EigResult:
+    """
+    Array API compatible wrapper for :py:func:`np.linalg.eig <numpy.linalg.eig>`.
+
+    See its docstring for more information.
+    """
+    # Note: the restriction to floating-point dtypes only is different from
+    # np.linalg.eig.
+    if x.dtype not in _floating_dtypes:
+        raise TypeError('Only floating-point dtypes are allowed in eig')
+
+    w, vr = np.linalg.eig(x._array)
+
+    # numpy return reals for real inputs
+    res_dtype = w.dtype
+    if w.dtype == np.float32:
+        res_dtype = np.complex64
+    elif w.dtype == np.float64:
+        res_dtype = np.complex128
+
+    if res_dtype != w.dtype:
+        w = w.astype(res_dtype)
+        vr = vr.astype(res_dtype)
+
+    return EigResult(Array._new(w, device=x.device), Array._new(vr, device=x.device))
+
+
 @requires_extension('linalg')
 def inv(x: Array, /) -> Array:
     """