Merge branch 'master' into 243-fix-write-methods-dont-work-after-redirectoutput

Author: Joao-Dionisio

.github/workflows/integration-test.yml

@@ -1,7 +1,7 @@
 name: Integration test
 
 env:
-  version: 9.1.0
+  version: 9.2.0
 
 # runs on branches and pull requests; doesn't run on tags.
 on:
@@ -57,7 +57,7 @@ jobs:
 
       - name: Download dependencies (SCIPOptSuite)
         shell: powershell
-        run: wget https://github.com/scipopt/scip/releases/download/$(echo "v${{env.version}}" | tr -d '.')/SCIPOptSuite-${{ env.version }}-win64-VS15.exe -outfile scipopt-installer.exe
+        run: wget https://github.com/scipopt/scip/releases/download/$(echo "v${{env.version}}" | tr -d '.')/SCIPOptSuite-${{ env.version }}-win64.exe -outfile scipopt-installer.exe
 
       - name: Install dependencies (SCIPOptSuite)
         shell: cmd
@@ -93,33 +93,13 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
-      - name: Cache dependencies (SCIPOptSuite)
-        id: cache-scip
-        uses: actions/cache@v2
-        with:
-          path: |
-            ${{ runner.workspace }}/scipoptsuite
-            ~/Library/Caches/Homebrew/tbb--*
-              /usr/local/opt/tbb*
-            ~/Library/Caches/Homebrew/downloads/*--tbb-*
-            ~/Library/Caches/Homebrew/boost--*
-              /usr/local/opt/boost*
-            ~/Library/Caches/Homebrew/downloads/*--boost-*
-          key: ${{ runner.os }}-scipopt-${{ env.version }}-${{ hashFiles('**/lockfiles') }}
-          restore-keys: |
-            ${{ runner.os }}-scipopt-${{ env.version }}-
-
       - name: Install dependencies (SCIPOptSuite)
-        if: steps.cache-scip.outputs.cache-hit != 'true'
         run: |
           brew install tbb boost bison
-          wget --quiet --no-check-certificate https://github.com/scipopt/scip/releases/download/$(echo "v${{env.version}}" | tr -d '.')/scipoptsuite-${{ env.version }}.tgz
-          tar xfz scipoptsuite-${{ env.version }}.tgz
-          cd scipoptsuite-${{ env.version }}
-          mkdir build
-          cd build
-          cmake .. -DCMAKE_BUILD_TYPE=Debug -DCMAKE_INSTALL_PREFIX=${{ runner.workspace }}/scipoptsuite -DIPOPT=off -DSYM=none -DTPI=tny -DREADLINE=off
-          make install -j
+          wget --quiet --no-check-certificate https://github.com/scipopt/scip/releases/download/$(echo "v${{env.version}}" | tr -d '.')/SCIPOptSuite-${{ env.version }}-Darwin.sh
+          chmod +x SCIPOptSuite-${{ env.version }}-Darwin.sh
+          ./SCIPOptSuite-${{ env.version }}-Darwin.sh --skip-license --include-subdir
+          mv SCIPOptSuite-${{ env.version }}-Darwin ${{ runner.workspace }}/scipoptsuite
 
       - name: Setup python ${{ matrix.python-version }}
         uses: actions/setup-python@v4

CHANGELOG.md

@@ -2,11 +2,14 @@
 
 ## Unreleased
 ### Added
+- Added categorical data example
+- Added printProblem to print problem to stdout
 - Added stage checks to presolve, freereoptsolve, freetransform
 - Added primal_dual_evolution recipe and a plot recipe
 ### Fixed
 - Only redirect stdout and stderr in redirectOutput() so that file output still works afterwards
 ### Changed
+- GitHub actions using Mac now use precompiled SCIP from latest release
 ### Removed
 
 ## 5.2.1 - 2024.10.29

examples/finished/categorical_data.py

@@ -0,0 +1,73 @@
+"""
+This example shows how one can optimize a model with categorical data by converting it into integers.
+
+There are three employees (Alice, Bob, Charlie) and three shifts. Each shift is assigned an integer:
+
+Morning   - 0
+Afternoon - 1
+Night     - 2
+
+The employees have availabilities (e.g. Alice can only work in the Morning and Afternoon), and different
+salary demands. These constraints, and an additional one stipulating that every shift must be covered,
+allows us to model a MIP with the objective of minimizing the money spent on salary.
+"""
+
+from pyscipopt import Model
+
+# Define categorical data
+shift_to_int = {"Morning": 0, "Afternoon": 1, "Night": 2}
+employees    = ["Alice", "Bob", "Charlie"]
+
+# Employee availability
+availability = {
+    "Alice": ["Morning", "Afternoon"],
+    "Bob": ["Afternoon", "Night"],
+    "Charlie": ["Morning", "Night"]
+}
+
+# Transform availability into integer values
+availability_int = {}
+for emp, available_shifts in availability.items():
+    availability_int[emp] = [shift_to_int[shift] for shift in available_shifts] 
+
+
+# Employees have different salary demands
+cost = {
+    "Alice":   [2,4,1],
+    "Bob":     [3,2,7],
+    "Charlie": [3,3,3]
+}
+
+# Create the model
+model = Model("Shift Assignment")
+
+# x[e, s] = 1 if employee e is assigned to shift s
+x = {}
+for e in employees:
+    for s in shift_to_int.values():
+        x[e, s] = model.addVar(vtype="B", name=f"x({e},{s})")
+
+# Each shift must be assigned to exactly one employee
+for s in shift_to_int.values():
+    model.addCons(sum(x[e, s] for e in employees) == 1)
+
+# Employees can only work shifts they are available for
+for e in employees:
+    for s in shift_to_int.values():
+        if s not in availability_int[e]:
+            model.addCons(x[e, s] == 0)
+
+# Minimize shift assignment cost
+model.setObjective(
+    sum(cost[e][s]*x[e, s] for e in employees for s in shift_to_int.values()), "minimize"
+)
+
+# Solve the problem
+model.optimize()
+
+# Display the results
+print("\nOptimal Shift Assignment:")
+for e in employees:
+    for s, s_id in shift_to_int.items():
+        if model.getVal(x[e, s_id]) > 0.5:
+            print("%s is assigned to %s" % (e, s))

src/pyscipopt/scip.pxi

@@ -2901,6 +2901,32 @@ cdef class Model:
         if not onlyroot:
             self.setIntParam("propagating/maxrounds", 0)
 
+    def printProblem(self, ext='.cip', trans=False, genericnames=False):
+        """
+        Write current model/problem to standard output.
+
+        Parameters
+        ----------
+        ext   : str, optional
+            the extension to be used (Default value = '.cip').
+            Should have an extension corresponding to one of the readable file formats,
+            described in https://www.scipopt.org/doc/html/group__FILEREADERS.php.
+        trans : bool, optional
+            indicates whether the transformed problem is written to file (Default value = False)
+        genericnames : bool, optional
+            indicates whether the problem should be written with generic variable
+            and constraint names (Default value = False)
+        """
+        user_locale = locale.getlocale(category=locale.LC_NUMERIC)
+        locale.setlocale(locale.LC_NUMERIC, "C")
+
+        if trans:
+            PY_SCIP_CALL(SCIPwriteTransProblem(self._scip, NULL, str_conversion(ext)[1:], genericnames))
+        else:
+            PY_SCIP_CALL(SCIPwriteOrigProblem(self._scip, NULL, str_conversion(ext)[1:], genericnames))            
+
+        locale.setlocale(locale.LC_NUMERIC,user_locale)
+    
     def writeProblem(self, filename='model.cip', trans=False, genericnames=False, verbose=True):
         """
         Write current model/problem to a file.
@@ -2923,22 +2949,27 @@ cdef class Model:
         user_locale = locale.getlocale(category=locale.LC_NUMERIC)
         locale.setlocale(locale.LC_NUMERIC, "C")
 
-        str_absfile = abspath(filename)
-        absfile = str_conversion(str_absfile)
-        fn, ext = splitext(absfile)
-
-        if len(ext) == 0:
-            ext = str_conversion('.cip')
-        fn = fn + ext
-        ext = ext[1:]
-
-        if trans:
-            PY_SCIP_CALL(SCIPwriteTransProblem(self._scip, fn, ext, genericnames))
+        if filename:
+            str_absfile = abspath(filename)
+            absfile = str_conversion(str_absfile)
+            fn, ext = splitext(absfile)
+            if len(ext) == 0:
+                ext = str_conversion('.cip')
+            fn = fn + ext
+            ext = ext[1:]
+            
+            if trans:
+                PY_SCIP_CALL(SCIPwriteTransProblem(self._scip, fn, ext, genericnames))
+            else:
+                PY_SCIP_CALL(SCIPwriteOrigProblem(self._scip, fn, ext, genericnames))
+            
+            if verbose:
+                print('wrote problem to file ' + str_absfile)
         else:
-            PY_SCIP_CALL(SCIPwriteOrigProblem(self._scip, fn, ext, genericnames))
-        
-        if verbose:
-            print('wrote problem to file ' + str_absfile)
+            if trans:
+                PY_SCIP_CALL(SCIPwriteTransProblem(self._scip, NULL, str_conversion('.cip')[1:], genericnames))
+            else:
+                PY_SCIP_CALL(SCIPwriteOrigProblem(self._scip, NULL, str_conversion('.cip')[1:], genericnames))            
 
         locale.setlocale(locale.LC_NUMERIC,user_locale)
 

tests/test_model.py

@@ -68,6 +68,7 @@ def test_model():
 
     s.writeProblem('model')
     s.writeProblem('model.lp')
+    s.printProblem()
 
     s.freeProb()
     s = Model()