InitialSolution

.github/workflows/main.yml

@@ -8,7 +8,10 @@ on:
 
 jobs:
   coverage:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
+    env:
+      CC: gcc-11
+      CXX: g++-11
     steps:
       - uses: actions/checkout@v3
       - uses: turtlebrowser/get-conan@main
@@ -55,7 +58,10 @@ jobs:
       - name: Run Tests
         run: ./build/test/Release/tests.exe
   test_without_conan:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
+    env:
+      CC: gcc-11
+      CXX: g++-11
     steps:
       - uses: actions/checkout@v3
       - name: Install parallelism library for C++
@@ -74,11 +80,29 @@ jobs:
           make -j tests
       - name: Run tests
         run: ./test/tests
-  test_release_inx:
-    strategy:
-      matrix:
-        os: [ ubuntu-latest, macos-13 ]
-    runs-on: ${{ matrix.os }}
+  test_release_mac:
+    runs-on: macos-13
+    steps:
+      - uses: actions/checkout@v3
+      - uses: turtlebrowser/get-conan@main
+      - name: Run Conan Install
+        run: |
+          conan profile detect
+          pushd ~/.conan2/profiles
+          sed -i'' -e 's/gnu17/17/g' *
+          popd
+          conan install -of . -o with_tests=True --build=missing .
+      - name: Run CMake
+        run: cmake --preset conan-release .
+      - name: Compile
+        run: cmake --build build/Release --target tests
+      - name: Run Tests
+        run: ./build/Release/test/tests
+  test_release_linux:
+    runs-on: ubuntu-22.04
+    env:
+      CC: gcc-11
+      CXX: g++-11
     steps:
       - uses: actions/checkout@v3
       - uses: turtlebrowser/get-conan@main
@@ -96,7 +120,10 @@ jobs:
       - name: Run Tests
         run: ./build/Release/test/tests
   clang_tidy:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
+    env:
+      CC: gcc-11
+      CXX: g++-11
     steps:
       - uses: actions/checkout@v3
       - uses: turtlebrowser/get-conan@main
@@ -112,7 +139,7 @@ jobs:
       - name: Run Clang-Tidy
         run: clang-tidy-14 -p build/Release source/*.cpp include/**/*.hpp
   clang_format:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v3
       - uses: DoozyX/[email protected]
@@ -121,7 +148,7 @@ jobs:
           extensions: 'hpp,cpp'
           clangFormatVersion: 17
   doxygen:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v3
       - uses: ssciwr/doxygen-install@v1

changelog.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Added
 
+- [PR31](https://github.com/scipopt/SCIPpp/pull/31) Add `InitialSolution` and `Model::addSolution`.
 - [PR28](https://github.com/scipopt/SCIPpp/pull/28) Add `Var::getVar`.
 
 ## [1.2.0] - 2024-05-21

include/scippp/initial_solution.hpp

@@ -0,0 +1,42 @@
+#pragma once
+
+#include <map>
+
+namespace scippp {
+
+// forward declare
+class Var;
+
+/**
+ * A primal solution to be added to %SCIP's solution pool.
+ *
+ * @since 1.3.0
+ */
+class InitialSolution {
+    friend class Model;
+    //! Variable assignment in the initial solution.
+    std::map<const Var*, double> m_values {};
+
+public:
+    /**
+     * Sets the value for a variable in the solution.
+     *
+     * @since 1.3.0
+     * @param var Variable to assign a value to.
+     * @param value to assign to the variable.
+     */
+    void setValue(const Var& var, double value);
+
+    /**
+     * Access the mutable value assigned to the variable.
+     *
+     * Initializes the assigned value to 0 if no value was assigned to the variable so far.
+     *
+     * @since 1.3.0
+     * @param var Variable to manipulate the value in the solution for.
+     * @return Mutable value assigned to the variable.
+     */
+    double& operator()(const Var& var);
+};
+
+}

include/scippp/model.hpp

@@ -11,6 +11,7 @@
 #include <vector>
 
 #include "scippp/constant_coefficient.hpp"
+#include "scippp/initial_solution.hpp"
 #include "scippp/lin_expr.hpp"
 #include "scippp/lin_ineq.hpp"
 #include "scippp/param.hpp"
@@ -326,5 +327,25 @@ class Model {
                     That is only required for use-cases not supported by SCIP++.
                     Consider adding the feature you are using to SCIP++!)")]] [[nodiscard]] Scip*
     scip() const;
+
+    /**
+     * Adds a solution to %SCIP's solution pool.
+     *
+     * @since 1.3.0
+     * @param initialSolution to add to the solution pool.
+     * @param printReason Should all reasons of violations be printed?
+     * @param completely Should all violations be checked if \p printReason is true?
+     * @param checkBounds Should the bounds of the variables be checked?
+     * @param checkIntegrality Should integrality be checked?
+     * @param checkLpRows Do constraints represented by rows in the current LP have to be checked?
+     * @return \c true iff the solution was feasible and stored in the solution storage (i.e, good enough to keep).
+     */
+    bool addSolution(
+        const InitialSolution& initialSolution,
+        bool printReason = true,
+        bool completely = true,
+        bool checkBounds = true,
+        bool checkIntegrality = true,
+        bool checkLpRows = true);
 };
 }

source/initial_solution.cpp

@@ -0,0 +1,15 @@
+#include "scippp/initial_solution.hpp"
+
+namespace scippp {
+
+void InitialSolution::setValue(const Var& var, double value)
+{
+    m_values[&var] = value;
+}
+
+double& InitialSolution::operator()(const Var& var)
+{
+    return m_values[&var];
+}
+
+}

source/model.cpp

@@ -150,4 +150,29 @@ double Model::getPrimalbound() const
     return SCIPgetPrimalbound(m_scip);
 }
 
+bool Model::addSolution(
+    const InitialSolution& initialSolution,
+    bool printReason,
+    bool completely,
+    bool checkBounds,
+    bool checkIntegrality,
+    bool checkLpRows)
+{
+    SCIP_Sol* sol { nullptr };
+    m_scipCallWrapper(SCIPcreateSol(m_scip, &sol, nullptr));
+    for (const auto& [var, value] : initialSolution.m_values) {
+        m_scipCallWrapper(SCIPsetSolVal(m_scip, sol, var->getVar(), value));
+    }
+    SCIP_Bool isFeasible { false };
+    m_scipCallWrapper(SCIPcheckSol(
+        m_scip, sol, printReason, completely, checkBounds, checkIntegrality, checkLpRows, &isFeasible));
+    SCIP_Bool isStored { false };
+    if (isFeasible) {
+        m_scipCallWrapper(SCIPaddSolFree(m_scip, &sol, &isStored));
+    } else {
+        m_scipCallWrapper(SCIPfreeSol(m_scip, &sol));
+    }
+    return isStored;
+}
+
 }

test/test_initial_solution.cpp

@@ -0,0 +1,57 @@
+#include <boost/test/unit_test.hpp>
+
+#include <boost/test/data/test_case.hpp>
+
+#include "scippp/model.hpp"
+
+using namespace scippp;
+using namespace std;
+namespace bdata = boost::unit_test::data;
+
+BOOST_AUTO_TEST_SUITE(InitSolution)
+
+BOOST_DATA_TEST_CASE(InitialSolutionStored, bdata::make({ 1, 2, 3 }), indexSetToOne)
+{
+    Model model("Simple");
+    auto x1 = model.addVar("x_1", 1, VarType::BINARY);
+    auto x2 = model.addVar("x_2", 1, VarType::BINARY);
+    auto x3 = model.addVar("x_3", 1, VarType::BINARY);
+    model.addConstr(x1 + x2 + x3 <= 1, "upperBound");
+    model.setObjsense(Sense::MAXIMIZE);
+
+    InitialSolution is;
+    is.setValue(x1, indexSetToOne == 1 ? 1 : 0);
+    is.setValue(x2, indexSetToOne == 2 ? 1 : 0);
+    is.setValue(x3, indexSetToOne == 3 ? 1 : 0);
+    BOOST_TEST(model.addSolution(is));
+
+    BOOST_REQUIRE(model.getNSols() > 0);
+    auto sol = model.getBestSol();
+    BOOST_TEST(x1.getSolValAsInt(sol) == (indexSetToOne == 1 ? 1 : 0));
+    BOOST_TEST(x2.getSolValAsInt(sol) == (indexSetToOne == 2 ? 1 : 0));
+    BOOST_TEST(x3.getSolValAsInt(sol) == (indexSetToOne == 3 ? 1 : 0));
+}
+
+BOOST_AUTO_TEST_CASE(Infeasible)
+{
+    Model model("Simple");
+    auto x1 = model.addVar("x_1", 1, VarType::BINARY);
+    model.setObjsense(Sense::MAXIMIZE);
+    InitialSolution is;
+    is.setValue(x1, 2);
+    BOOST_TEST(!model.addSolution(is));
+}
+
+BOOST_AUTO_TEST_CASE(UpdateSolution)
+{
+    Model model("Simple");
+    const auto& [x1, x2] = model.addVars<2>("x_");
+    InitialSolution is;
+    is(x1) = 4;
+    is(x1) += 38;
+    is(x2) += 42;
+    BOOST_TEST(is(x1) == 42);
+    BOOST_TEST(is(x2) == 42);
+}
+
+BOOST_AUTO_TEST_SUITE_END()