Add Knitro solver support

README.md

@@ -150,6 +150,7 @@ Fri    0          4
 * [MOSEK](https://www.mosek.com/)
 * [COPT](https://www.shanshu.ai/copt)
 * [cuPDLPx](https://github.com/MIT-Lu-Lab/cuPDLPx)
+* [Knitro](https://www.artelys.com/solvers/knitro/)
 
 Note that these do have to be installed by the user separately.
 

doc/release_notes.rst

@@ -6,13 +6,19 @@ Upcoming Version
 
 * Fix docs (pick highs solver)
 * Add the `sphinx-copybutton` to the documentation
+* Add support for the `knitro` solver via the knitro python API
 
 Version 0.6.1
 --------------
 
 * Avoid Gurobi initialization on linopy import.
 * Fix LP file writing for negative zero (-0.0) values that produced invalid syntax like "+-0.0" rejected by Gurobi
 
+* Fix compatibility for xpress versions below 9.6 (regression)
+* Add support for the Artelys Knitro solver (via the Knitro Python API)
+* Performance: Up to 50x faster ``repr()`` for variables/constraints via O(log n) label lookup and direct numpy indexing
+* Performance: Up to 46x faster ``ncons`` property by replacing ``.flat.labels.unique()`` with direct counting
+
 Version 0.6.0
 --------------
 

linopy/solver_capabilities.py

@@ -161,6 +161,17 @@ def supports(self, feature: SolverFeature) -> bool:
             }
         ),
     ),
+    "knitro": SolverInfo(
+        name="knitro",
+        display_name="Artelys Knitro",
+        features=frozenset(
+            {
+                SolverFeature.QUADRATIC_OBJECTIVE,
+                SolverFeature.LP_FILE_NAMES,
+                SolverFeature.SOLUTION_FILE_NOT_NEEDED,
+            }
+        ),
+    ),
     "scip": SolverInfo(
         name="scip",
         display_name="SCIP",