Add a glop sample

cmake/glop.cmake

@@ -235,21 +235,6 @@ endif()
 # ALIAS
 add_library(${PROJECT_NAME}::glop ALIAS glop)
 
-if(APPLE)
-  set(CMAKE_INSTALL_RPATH
-    "@loader_path/../${CMAKE_INSTALL_LIBDIR};@loader_path")
-elseif(UNIX)
-  set(CMAKE_INSTALL_RPATH "$ORIGIN/../${CMAKE_INSTALL_LIBDIR}:$ORIGIN")
-endif()
-
-add_executable(glopbin "")
-file(GENERATE
-  OUTPUT ${PROJECT_BINARY_DIR}/glop/main.cpp
-  CONTENT "int main(int, char**) {return 0;}")
-target_sources(glopbin PRIVATE ${PROJECT_BINARY_DIR}/glop/main.cpp)
-
-target_link_libraries(glopbin PRIVATE glop)
-
 # Install rules
 include(GNUInstallDirs)
 include(GenerateExportHeader)
@@ -365,3 +350,5 @@ install(
   DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/glop"
   COMPONENT Devel)
 
+# Build glop samples
+add_subdirectory(ortools/glop/samples)

ortools/glop/samples/BUILD

@@ -0,0 +1,3 @@
+load(":code_samples.bzl", "code_sample_cc")
+
+code_sample_cc(sample = "simple_glop_program")

ortools/glop/samples/CMakeLists.txt

@@ -0,0 +1,31 @@
+if(NOT BUILD_SAMPLES AND NOT BUILD_GLOP)
+  return()
+endif()
+
+
+if(BUILD_GLOP)
+  if(APPLE)
+    set(CMAKE_INSTALL_RPATH
+      "@loader_path/../${CMAKE_INSTALL_LIBDIR};@loader_path")
+  elseif(UNIX)
+    set(CMAKE_INSTALL_RPATH "$ORIGIN/../${CMAKE_INSTALL_LIBDIR}:$ORIGIN")
+  endif()
+
+  add_executable(simple_glop_program simple_glop_program.cc)
+  target_include_directories(simple_glop_program PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+  target_compile_features(simple_glop_program PRIVATE cxx_std_17)
+  target_link_libraries(simple_glop_program PRIVATE glop)
+
+  install(TARGETS simple_glop_program)
+
+  if(BUILD_TESTING)
+    add_test(NAME cxx_simple_glop_program COMMAND simple_glop_program)
+  endif()
+endif()
+
+if(BUILD_CXX_SAMPLES)
+  file(GLOB CXX_SRCS "*.cc")
+  foreach(SAMPLE IN LISTS CXX_SRCS)
+    add_cxx_sample(${SAMPLE})
+  endforeach()
+endif()

ortools/glop/samples/code_samples.bzl

@@ -0,0 +1,23 @@
+def code_sample_cc(sample):
+  native.cc_binary(
+      name = sample,
+      srcs = [sample + ".cc"],
+      deps = [
+        "//ortools/base",
+        "//ortools/glop:lp_solver",
+        "//ortools/lp_data",
+      ],
+  )
+
+  native.cc_test(
+      name = sample+"_test",
+      size = "small",
+      srcs = [sample + ".cc"],
+      deps = [
+        ":"+sample,
+        "//ortools/base",
+        "//ortools/glop:lp_solver",
+        "//ortools/lp_data",
+      ],
+  )
+

ortools/glop/samples/simple_glop_program.cc

@@ -0,0 +1,54 @@
+#include <iostream>
+#include "ortools/glop/lp_solver.h"
+#include "ortools/lp_data/lp_data.h"
+#include "ortools/lp_data/lp_types.h"
+
+namespace operations_research::glop {
+  int RunLinearExample() {
+    LinearProgram linear_program;
+    // Create the variables x and y.
+    ColIndex col_x = linear_program.FindOrCreateVariable("x");
+    linear_program.SetVariableBounds(col_x, 0.0, 1.0);
+    ColIndex col_y = linear_program.FindOrCreateVariable("y");
+    linear_program.SetVariableBounds(col_y, 0.0, 2.0);
+
+    // Create linear constraint: 0 <= x + y <= 2.
+    RowIndex row_r1 = linear_program.FindOrCreateConstraint("r1");
+    linear_program.SetConstraintBounds(row_r1, 0.0, 2.0);
+    linear_program.SetCoefficient(row_r1, col_x, 1);
+    linear_program.SetCoefficient(row_r1, col_y, 1);
+
+    // Create objective function: 3 * x + y.
+    linear_program.SetObjectiveCoefficient(col_x, 3);
+    linear_program.SetObjectiveCoefficient(col_y, 1);
+    linear_program.SetMaximizationProblem(true);
+
+    linear_program.CleanUp();
+
+    std::cout << "Number of variables = " << linear_program.num_variables() << std::endl;
+    std::cout << "Number of constraints = " << linear_program.num_constraints() << std::endl;
+
+    LPSolver solver;
+    GlopParameters parameters;
+    parameters.set_provide_strong_optimal_guarantee(true);
+    solver.SetParameters(parameters);
+
+    ProblemStatus status = solver.Solve(linear_program);
+    if (status == ProblemStatus::OPTIMAL) {
+      std::cout << "Optimal solution found !" << std::endl;
+      // The objective value of the solution.
+      std::cout << "Optimal objective value = " << solver.GetObjectiveValue() << std::endl;
+      // The value of each variable in the solution.
+      const DenseRow& values = solver.variable_values();
+      std::cout << "Solution:" << std::endl
+        << "x = " << values[col_x] << std::endl
+        << ", y = " << values[col_y] << std::endl;
+      return 0;
+    } else
+      return 1;
+  }
+}  // namespace operations_research::glop
+
+int main(int argc, char** argv) {
+  return operations_research::glop::RunLinearExample();
+}