Now using solution_.hasUndefined(); updated FEATURES.md and silenced …

…unti tests

FEATURES.md

@@ -4,3 +4,10 @@
 
 Added `int64_t mip_total_lp_iterations` to `HighsCallbackDataOut` and modified accessor function
 
+`Highs::writeSolution` and `Highs::writeBasis` now being done via `HighsIO` logging, so can be redirected to logging callback.
+
+Introduced `const double kHighsUndefined` as value of undefined values in a user solution. It's equal to `kHighsInf`
+
+Added `Highs::setSolution(const HighsInt num_entries, const HighsInt* index, const double* value);` to allow a sparse primal solution to be defined.
+
+

check/TestCallbacks.cpp

@@ -277,8 +277,8 @@ TEST_CASE("highs-callback-solution-basis-logging", "[highs-callback]") {
   highs.run();
   highs.setCallback(userInterruptCallback, p_user_callback_data);
   highs.startCallback(kCallbackLogging);
-  highs.writeSolution("", kSolutionStylePretty);
-  highs.writeBasis("");
+  if (dev_run) highs.writeSolution("", kSolutionStylePretty);
+  if (dev_run) highs.writeBasis("");
 }
 
 TEST_CASE("highs-callback-simplex-interrupt", "[highs-callback]") {

src/lp_data/Highs.cpp

@@ -3406,14 +3406,7 @@ HighsStatus Highs::completeSolutionFromDiscreteAssignment() {
   HighsLp& lp = model_.lp_;
   // Determine whether the solution contains undefined values, in
   // order to decide whether to check its feasibility
-  bool contains_undefined_values = false;
-  for (HighsInt iCol = 0; iCol < lp.num_col_; iCol++) {
-    if (solution_.col_value[iCol] == kHighsUndefined) {
-      contains_undefined_values = true;
-      break;
-    }
-  }
-  assert(solution_.hasUndefined() == contains_undefined_values);
+  const bool contains_undefined_values = solution_.hasUndefined();
   if (!contains_undefined_values) {
     bool valid, integral, feasible;
     // Determine whether this solution is integer feasible
@@ -3466,6 +3459,7 @@ HighsStatus Highs::completeSolutionFromDiscreteAssignment() {
       }
     }
   }
+  assert(!solution_.hasUndefined());
   const HighsInt num_discrete_variable =
       num_unfixed_discrete_variable + num_fixed_discrete_variable;
   const HighsInt num_continuous_variable = lp.num_col_ - num_discrete_variable;