Direct and Persistent Interfaces to SCIP

.github/workflows/test_branches.yml

@@ -334,6 +334,12 @@ jobs:
                 || echo "WARNING: Xpress Community Edition is not available"
             python -m pip install --cache-dir cache/pip maingopy \
                 || echo "WARNING: MAiNGO is not available"
+            if [[ ${{matrix.python}} == pypy* ]]; then
+                echo "skipping SCIP for pypy"
+            else
+                python -m pip install --cache-dir cache/pip pyscipopt \
+                    || echo "WARNING: SCIP is not available"
+            fi
             if [[ ${{matrix.python}} == pypy* ]]; then
                 echo "skipping wntr for pypy"
             else
@@ -423,7 +429,7 @@ jobs:
             else
                 XPRESS='xpress'
             fi
-            for PKG in "$CPLEX" docplex gurobi "$XPRESS" cyipopt pymumps scip; do
+            for PKG in "$CPLEX" docplex gurobi "$XPRESS" cyipopt pymumps scip pyscipopt; do
                 echo ""
                 echo "*** Install $PKG ***"
                 echo ""

.github/workflows/test_pr_and_main.yml

@@ -381,6 +381,12 @@ jobs:
                 || echo "WARNING: Xpress Community Edition is not available"
             python -m pip install --cache-dir cache/pip maingopy \
                 || echo "WARNING: MAiNGO is not available"
+            if [[ ${{matrix.python}} == pypy* ]]; then
+                echo "skipping SCIP for pypy"
+            else
+                python -m pip install --cache-dir cache/pip pyscipopt \
+                    || echo "WARNING: SCIP is not available"
+            fi
             if [[ ${{matrix.python}} == pypy* ]]; then
                 echo "skipping wntr for pypy"
             else
@@ -470,7 +476,7 @@ jobs:
             else
                 XPRESS='xpress'
             fi
-            for PKG in "$CPLEX" docplex gurobi "$XPRESS" cyipopt pymumps scip; do
+            for PKG in "$CPLEX" docplex gurobi "$XPRESS" cyipopt pymumps scip pyscipopt; do
                 echo ""
                 echo "*** Install $PKG ***"
                 echo ""

doc/OnlineDocs/explanation/experimental/solvers.rst

@@ -45,6 +45,9 @@ with existing interfaces).
    * - Ipopt
      - ``ipopt``
      - ``ipopt_v2``
+   * - GAMS
+     - ``gams``
+     - ``gams_v2``
    * - Gurobi (persistent)
      - ``gurobi_persistent``
      - ``gurobi_persistent_v2``
@@ -57,9 +60,12 @@ with existing interfaces).
    * - KNITRO
      - ``knitro_direct``
      - ``knitro_direct``
-   * - GAMS
-     - ``gams``
-     - ``gams_v2``
+   * - SCIP (direct)
+     - ``scip_direct``
+     - ``scip_direct``
+   * - SCIP (persistent)
+     - ``scip_persistent``
+     - ``scip_persistent``
 
 Using the new interfaces through the legacy interface
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

doc/OnlineDocs/getting_started/solvers.rst

@@ -76,11 +76,16 @@ the license requirements for their desired solver.
      - ``conda install ‑c conda‑forge pymumps``
      - `License <https://github.com/PyMumps/pymumps/blob/master/LICENSE.txt>`__
        `Docs <https://github.com/pymumps/pymumps>`__
-   * - SCIP
+   * - SCIP (Command-line)
      - N/A
      - ``conda install ‑c conda‑forge scip``
      - `License <https://www.scipopt.org/scip/doc/html/LICENSE.php>`__
        `Docs <https://www.scipopt.org/index.php#download>`__
+   * - SCIP (Python)
+     - ``pip install pyscipopt``
+     - ``conda install ‑c conda‑forge pyscipopt``
+     - `License <https://www.scipopt.org/scip/doc/html/LICENSE.php>`__
+       `Docs <https://www.scipopt.org/index.php#download>`__
    * - XPRESS
      - ``pip install xpress``
      - ``conda install ‑c fico‑xpress xpress``

pyomo/contrib/solver/common/solution_loader.py

@@ -20,6 +20,9 @@
 from pyomo.core.staleflag import StaleFlagManager
 from pyomo.core.base.suffix import Suffix
 from .util import NoSolutionError
+import logging
+
+logger = logging.getLogger(__name__)
 
 
 class SolutionLoader:

pyomo/contrib/solver/plugins.py

@@ -14,6 +14,8 @@
 from .solvers.gurobi.gurobi_persistent import GurobiPersistent
 from .solvers.gurobi.gurobi_direct_minlp import GurobiDirectMINLP
 from .solvers.highs import Highs
+from .solvers.scip.scip_direct import ScipDirect
+from .solvers.scip.scip_persistent import ScipPersistent
 from .solvers.gams import GAMS
 from .solvers.knitro.direct import KnitroDirectSolver
 
@@ -22,6 +24,9 @@ def load():
     SolverFactory.register(
         name="ipopt", legacy_name="ipopt_v2", doc="The IPOPT NLP solver"
     )(Ipopt, LegacyIpoptSolver)
+    SolverFactory.register(name='gams', legacy_name='gams_v2', doc='Interface to GAMS')(
+        GAMS
+    )
     SolverFactory.register(
         name="gurobi_persistent",
         legacy_name="gurobi_persistent_v2",
@@ -40,11 +45,16 @@ def load():
     SolverFactory.register(
         name="highs", legacy_name="highs", doc="Persistent interface to HiGHS"
     )(Highs)
-    SolverFactory.register(name='gams', legacy_name='gams_v2', doc='Interface to GAMS')(
-        GAMS
-    )
     SolverFactory.register(
         name="knitro_direct",
         legacy_name="knitro_direct",
         doc="Direct interface to KNITRO solver",
     )(KnitroDirectSolver)
+    SolverFactory.register(
+        name='scip_direct', legacy_name='scip_direct', doc='Direct interface pyscipopt'
+    )(ScipDirect)
+    SolverFactory.register(
+        name='scip_persistent',
+        legacy_name='scip_persistent',
+        doc='Persistent interface pyscipopt',
+    )(ScipPersistent)

pyomo/contrib/solver/solvers/scip/__init__.py

@@ -0,0 +1,8 @@
+# ____________________________________________________________________________________
+#
+# Pyomo: Python Optimization Modeling Objects
+# Copyright (c) 2008-2026 National Technology and Engineering Solutions of Sandia, LLC
+# Under the terms of Contract DE-NA0003525 with National Technology and Engineering
+# Solutions of Sandia, LLC, the U.S. Government retains certain rights in this
+# software.  This software is distributed under the 3-clause BSD License.
+# ____________________________________________________________________________________