python: Provide incumbent solution in callback

ERGO-Code · Aug 21, 2024 · d712b85 · d712b85
1 parent 53273e7
commit d712b85
Show file tree

Hide file tree

Showing 4 changed files with 9 additions and 4 deletions.
diff --git a/examples/call_highs_from_python.py b/examples/call_highs_from_python.py
@@ -248,7 +248,7 @@ def user_interrupt_callback(
             print(f"userCallback(type {callback_type};")
             print(f"data {local_callback_data:.4g}): {message}")
             print(f"with objective {data_out.objective_function_value}")
-            print(f"and solution[0] = {data_out.mip_solution[0]}")
+            print(f"and solution = {data_out.mip_solution}")
 
         # Check and update the objective function value
         assert (

diff --git a/src/highs_bindings.cpp b/src/highs_bindings.cpp
@@ -1195,12 +1195,11 @@ PYBIND11_MODULE(_core, m) {
       .def_property(
           "mip_solution",
           [](const HighsCallbackDataOut& self) -> py::array {
-            // XXX: This is clearly wrong, most likely we need to have the
-            // length as an input data parameter
-            return py::array(3, self.mip_solution);
+            return py::array(self.mip_solution_size, self.mip_solution);
           },
           [](HighsCallbackDataOut& self, py::array_t<double> new_mip_solution) {
                       self.mip_solution = new_mip_solution.mutable_data();
+                      self.mip_solution_size = new_mip_solution.shape(0);
           });
   py::class_<HighsCallbackDataIn>(callbacks, "HighsCallbackDataIn")
       .def(py::init<>())

diff --git a/src/lp_data/HighsCallbackStruct.h b/src/lp_data/HighsCallbackStruct.h
@@ -37,6 +37,7 @@ typedef struct {
   double mip_dual_bound;
   double mip_gap;
   double* mip_solution;
+  HighsInt mip_solution_size;
   HighsInt cutpool_num_col;
   HighsInt cutpool_num_cut;
   HighsInt cutpool_num_nz;

diff --git a/src/mip/HighsMipSolverData.cpp b/src/mip/HighsMipSolverData.cpp
@@ -463,6 +463,8 @@ void HighsMipSolverData::runSetup() {
       assert(!mipsolver.submip);
       mipsolver.callback_->clearHighsCallbackDataOut();
       mipsolver.callback_->data_out.mip_solution = mipsolver.solution_.data();
+      mipsolver.callback_->data_out.mip_solution_size =
+          mipsolver.solution_.size();
       const bool interrupt = interruptFromCallbackWithData(
           kCallbackMipSolution, mipsolver.solution_objective_,
           "Feasible solution");
@@ -832,6 +834,7 @@ double HighsMipSolverData::transformNewIntegerFeasibleSolution(
       mipsolver.callback_->active[kCallbackMipSolution]) {
     mipsolver.callback_->clearHighsCallbackDataOut();
     mipsolver.callback_->data_out.mip_solution = solution.col_value.data();
+    mipsolver.callback_->data_out.mip_solution_size = solution.col_value.size();
     const bool interrupt = interruptFromCallbackWithData(
         kCallbackMipSolution, mipsolver_objective_value, "Feasible solution");
     assert(!interrupt);
@@ -1928,6 +1931,8 @@ void HighsMipSolverData::saveReportMipSolution(const double new_upper_limit) {
     if (mipsolver.callback_->active[kCallbackMipImprovingSolution]) {
       mipsolver.callback_->clearHighsCallbackDataOut();
       mipsolver.callback_->data_out.mip_solution = mipsolver.solution_.data();
+      mipsolver.callback_->data_out.mip_solution_size =
+          mipsolver.solution_.size();
       const bool interrupt = interruptFromCallbackWithData(
           kCallbackMipImprovingSolution, mipsolver.solution_objective_,
           "Improving solution");