python-control · jamestjsp · Jan 31, 2026 · Jan 31, 2026 · Jan 31, 2026 · Jan 31, 2026
diff --git a/.github/workflows/doctest.yml b/.github/workflows/doctest.yml
@@ -27,7 +27,8 @@ jobs:
     - name: Install full dependencies
       shell: bash -l {0}
       run: |
-        mamba install cvxopt pandas slycot 
+        mamba install cvxopt pandas
+        pip install 'slicot>=1.0.12'
 
     - name: Run doctest
       shell: bash -l {0}

diff --git a/.github/workflows/install_examples.yml b/.github/workflows/install_examples.yml
@@ -20,8 +20,9 @@ jobs:
            --quiet --yes \
            python=3.12 pip \
            numpy matplotlib scipy \
-           slycot pmw jupyter \
+           pmw jupyter \
            ipython!=9.0
+        conda run -n control-examples-env pip install 'slicot>=1.0.12'
 
     - name: Install from source
       run: |

diff --git a/.github/workflows/python-package-conda.yml b/.github/workflows/python-package-conda.yml
@@ -6,7 +6,7 @@ jobs:
   test-linux-conda:
     name: >
       Py${{ matrix.python-version }};
-      ${{ matrix.slycot || 'no' }} Slycot;
+      ${{ matrix.slycot && 'slycot' || matrix.slicot && 'slicot' || 'no-slicot' }};
       ${{ matrix.pandas || 'no' }} Pandas;
       ${{ matrix.cvxopt || 'no' }} CVXOPT
       ${{ matrix.mplbackend && format('; {0}', matrix.mplbackend) }}
@@ -18,6 +18,7 @@ jobs:
       matrix:
         python-version: ['3.10', '3.12']
         slycot: ["", "conda"]
+        slicot: [""]
         pandas: [""]
         cvxopt: ["", "conda"]
         mplbackend: [""]
@@ -27,6 +28,15 @@ jobs:
             pandas: conda
             cvxopt: conda
             mplbackend: QtAgg
+          # Test with slicot (pip) instead of slycot (conda)
+          - python-version: '3.12'
+            slicot: pip
+            slycot: ""
+            cvxopt: conda
+        exclude:
+          # Don't test both slycot and slicot together
+          - slycot: "conda"
+            slicot: "pip"
 
     steps:
     - uses: actions/checkout@v3
@@ -52,6 +62,9 @@ jobs:
         if [[ '${{matrix.slycot}}' == 'conda' ]]; then
           mamba install slycot
         fi
+        if [[ '${{matrix.slicot}}' == 'pip' ]]; then
+          pip install 'slicot>=1.0.12'
+        fi
         if [[ '${{matrix.pandas}}' == 'conda' ]]; then
           mamba install pandas
         fi
@@ -70,7 +83,7 @@ jobs:
     - name: report coverage
       uses: coverallsapp/github-action@v2
       with:
-        flag-name: conda-pytest_py${{ matrix.python-version }}_${{ matrix.slycot || 'no' }}-Slycot_${{ matrix.pandas || 'no' }}-Pandas_${{ matrix.cvxopt || 'no' }}_CVXOPT-${{ matrix.mplbackend && format('; {0}', matrix.mplbackend) }}
+        flag-name: conda-pytest_py${{ matrix.python-version }}_${{ matrix.slycot && 'slycot' || matrix.slicot && 'slicot' || 'no-slicot' }}_${{ matrix.pandas || 'no' }}-Pandas_${{ matrix.cvxopt || 'no' }}_CVXOPT-${{ matrix.mplbackend && format('; {0}', matrix.mplbackend) }}
         parallel: true
         file: coverage.xml
 

diff --git a/control/canonical.py b/control/canonical.py
@@ -10,7 +10,7 @@
 from numpy.linalg import matrix_rank, solve
 from scipy.linalg import schur
 
-from .exception import ControlNotImplemented, ControlSlycot
+from .exception import ControlNotImplemented, ControlSlicot
 from .iosys import issiso
 from .statefbk import ctrb, obsv
 from .statesp import StateSpace, _convert_to_statespace
@@ -330,15 +330,15 @@ def _bdschur_condmax_search(aschur, tschur, condmax):
 
     Notes
     -----
-    Outputs as for slycot.mb03rd.
+    Outputs as for slicot.mb03rd.
 
     `aschur`, `tschur` are as returned by scipy.linalg.schur.
 
     """
     try:
-        from slycot import mb03rd
+        from .slicot_compat import mb03rd
     except ImportError:
-        raise ControlSlycot("can't find slycot module 'mb03rd'")
+        raise ControlSlicot("can't find slicot module 'mb03rd'")
 
     # see notes on RuntimeError below
     pmaxlower = None

diff --git a/control/exception.py b/control/exception.py
@@ -5,10 +5,28 @@
 
 """Exception definitions for the control package."""
 
-class ControlSlycot(ImportError):
-    """Slycot import failed."""
+import warnings
+
+
+class ControlSlicot(ImportError):
+    """Slicot import failed."""
     pass
 
+
+def _deprecated_alias(old_name, new_name):
+    """Issue deprecation warning for renamed class/function."""
+    warnings.warn(
+        f"{old_name} is deprecated, use {new_name} instead",
+        DeprecationWarning, stacklevel=3
+    )
+
+
+class ControlSlycot(ControlSlicot):
+    """Deprecated alias for ControlSlicot."""
+    def __init__(self, *args, **kwargs):
+        _deprecated_alias('ControlSlycot', 'ControlSlicot')
+        super().__init__(*args, **kwargs)
+
 class ControlDimension(ValueError):
     """Raised when dimensions of system objects are not correct."""
     pass
@@ -29,18 +47,26 @@ class ControlNotImplemented(NotImplementedError):
     """Functionality is not yet implemented."""
     pass
 
-# Utility function to see if Slycot is installed
-slycot_installed = None
-def slycot_check():
-    """Return True if Slycot is installed, otherwise False."""
-    global slycot_installed
-    if slycot_installed is None:
+# Utility function to see if slicot or slycot is installed
+slicot_installed = None
+def slicot_check():
+    """Return True if slicot or slycot is installed, otherwise False."""
+    global slicot_installed
+    if slicot_installed is None:
         try:
-            import slycot  # noqa: F401
-            slycot_installed = True
-        except:
-            slycot_installed = False
-    return slycot_installed
+            import slicot  # noqa: F401
+            slicot_installed = True
+        except ImportError:
+            try:
+                import slycot  # noqa: F401
+                slicot_installed = True
+            except ImportError:
+                slicot_installed = False
+    return slicot_installed
+
+
+# Backwards-compatible alias (no warning to avoid noise in existing code)
+slycot_check = slicot_check
 
 
 # Utility function to see if pandas is installed

diff --git a/control/margins.py b/control/margins.py
@@ -16,7 +16,7 @@
 from .iosys import issiso
 from .ctrlutil import mag2db
 try:
-    from slycot import ab13md
+    from .slicot_compat import ab13md
 except ImportError:
     ab13md = None
 
@@ -577,7 +577,7 @@ def disk_margins(L, omega, skew=0.0, returnall=False):
     # Need slycot if L is MIMO, for mu calculation
     if not L.issiso() and ab13md == None:
         raise ControlMIMONotImplemented(
-            "Need slycot to compute MIMO disk_margins")
+            "Need slicot to compute MIMO disk_margins")
 
     # Get dimensions of feedback system
     num_loops = statesp.ss(L).C.shape[0]