Merge pull request #104 from qutech/py313

Add python 3.13 compatibility

Author: thangleiter

.github/workflows/main.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python_version: ['3.9', '3.10', '3.11', '3.12']
+        python_version: ['3.9', '3.10', '3.11', '3.12', '3.13']
         install_extras: ['tests', 'plotting,fancy_progressbar,tests', 'plotting,bloch_sphere_visualization,fancy_progressbar,doc,tests']
 
     steps:

filter_functions/superoperator.py

@@ -42,6 +42,7 @@
 import numpy as np
 from numpy import linalg as nla
 from numpy import ndarray
+from scipy import linalg as sla
 
 from . import basis as _b
 
@@ -181,7 +182,7 @@ def liouville_is_CP(
     """
 
     choi = liouville_to_choi(superoperator, basis)
-    D, V = nla.eigh(choi)
+    D, V = _robust_eigh(choi)
 
     CP = (D >= -(atol or basis._atol)).all(axis=-1)
 
@@ -254,11 +255,31 @@ def liouville_is_cCP(
     Q = np.eye(Omega.shape[-1]) - Omega
 
     choi = liouville_to_choi(superoperator, basis)
-    D, V = nla.eigh(Q @ choi @ Q)
+    D, V = _robust_eigh(Q @ choi @ Q)
 
     cCP = (D >= -(atol or basis._atol)).all(axis=-1)
 
     if return_eig:
         return cCP, (D, V)
 
     return cCP
+
+
+def _robust_eigh(a: ndarray) -> Tuple[ndarray, ndarray]:
+    """Try computing the eigenvalue decomposition using numpy's
+    vectorized but less robust (uses heevd driver) function and if it
+    fails resort to scipy's using the heevr driver."""
+    try:
+        D, V = nla.eigh(a)
+    except nla.LinAlgError:
+        shp = a.shape[:-2]
+        if a.ndim == 2:
+            a.shape = (1,) + a.shape
+        elif a.ndim > 3:
+            a.shape = (-1,) + a.shape[-2:]
+
+        D, V = map(np.array, zip(*(sla.eigh(c, driver='evr') for c in a)))
+        D.shape = shp + D.shape[-1:]
+        V.shape = shp + V.shape[-2:]
+
+    return D, V

pyproject.toml

@@ -19,6 +19,7 @@ classifiers = [
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
     "License :: OSI Approved :: GNU General Public License v3 or later (GPLv3+)",
     "Operating System :: OS Independent",
     "Topic :: Scientific/Engineering :: Physics",