Merge branch 'master' into aphi

.github/workflows/build_docs.yml

@@ -9,7 +9,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: actions/setup-python@v4
       with:
         # Semantic version range syntax or exact version of a Python version

.github/workflows/publish-to-test-pypi.yml

@@ -7,7 +7,7 @@ jobs:
     name: Build and publish Python 🐍 distributions 📦 to PyPI
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Python 3
       uses: actions/setup-python@v4
       with:

.github/workflows/pythonpackage.yml

@@ -12,7 +12,7 @@ jobs:
         os: [ubuntu-latest, macOS-latest, windows-latest]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:

pulp/apis/cplex_api.py

@@ -303,6 +303,7 @@ def __init__(
             logPath=None,
             epgap=None,
             logfilename=None,
+            threads=None,
         ):
             """
             :param bool mip: if False, assume LP even if integer variables
@@ -313,6 +314,7 @@ def __init__(
             :param str logPath: path to the log file
             :param float epgap: deprecated for gapRel
             :param str logfilename: deprecated for logPath
+            :param int threads: number of threads to be used by CPLEX to solve a problem (default None uses all available)
             """
             if epgap is not None:
                 warnings.warn("Parameter epgap is being depreciated for gapRel")
@@ -337,6 +339,7 @@ def __init__(
                 timeLimit=timeLimit,
                 warmStart=warmStart,
                 logPath=logPath,
+                threads=threads,
             )
 
         def available(self):
@@ -455,6 +458,7 @@ def cplex_var_types(var):
                 self.changeEpgap(gapRel)
             if self.timeLimit is not None:
                 self.setTimeLimit(self.timeLimit)
+            self.setThreads(self.optionsDict.get("threads", None))
             if self.optionsDict.get("warmStart", False):
                 # We assume "auto" for the effort_level
                 effort = self.solverModel.MIP_starts.effort_level.auto
@@ -478,6 +482,12 @@ def setlogfile(self, fileobj):
             self.solverModel.set_warning_stream(fileobj)
             self.solverModel.set_results_stream(fileobj)
 
+        def setThreads(self, threads=None):
+            """
+            Change cplex thread count used (None is default which uses all available resources)
+            """
+            self.solverModel.parameters.threads.set(threads or 0)
+
         def changeEpgap(self, epgap=10**-4):
             """
             Change cplex solver integer bound gap tolerence

pulp/tests/test_pulp.py

@@ -820,6 +820,29 @@ def test_pulp_123(self):
             else:
                 pulpTestCheck(prob, self.solver, [const.LpStatusUnbounded])
 
+        def test_msg_arg(self):
+            """
+            Test setting the msg arg to True does not interfere with solve
+            """
+            prob = LpProblem("test_msg_arg", const.LpMinimize)
+            x = LpVariable("x", 0, 4)
+            y = LpVariable("y", -1, 1)
+            z = LpVariable("z", 0)
+            w = LpVariable("w", 0)
+            prob += x + 4 * y + 9 * z, "obj"
+            prob += x + y <= 5, "c1"
+            prob += x + z >= 10, "c2"
+            prob += -y + z == 7, "c3"
+            prob += w >= 0, "c4"
+            data = prob.toDict()
+            var1, prob1 = LpProblem.fromDict(data)
+            x, y, z, w = (var1[name] for name in ["x", "y", "z", "w"])
+
+            self.solver.msg = True
+            pulpTestCheck(
+                prob1, self.solver, [const.LpStatusOptimal], {x: 4, y: -1, z: 6, w: 0}
+            )
+
         def test_pulpTestAll(self):
             """
             Test the availability of the function pulpTestAll