NLModel: allow empty obj #30

ampl · Feb 13, 2024 · a260eaa · a260eaa
1 parent a2e7d6c
commit a260eaa
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Showing 2 changed files with 8 additions and 5 deletions.
diff --git a/nl-writer2/include/mp/nl-model.h b/nl-writer2/include/mp/nl-model.h
@@ -69,7 +69,8 @@ class NLModel {
   /// Add linear objective (only single objective supported.)
   /// Sense: NLW2_ObjSenseM....
   /// Coefficients: dense vector.
-  void SetLinearObjective(int sense, double c0, const double* c)
+  void SetLinearObjective(int sense, double c0,
+                          const double* c = nullptr)
   { obj_sense_=sense; obj_c0_=c0; obj_c_=c; }
 
   /// Add Q for the objective quadratic part 0.5 @ x.T @ Q @ x.

diff --git a/nl-writer2/src/nl-solver.cc b/nl-writer2/src/nl-solver.cc
@@ -83,7 +83,7 @@ class NLFeeder2_Easy
       auto c = NLME().ObjCoefficients();
       for (int j=0; j<header_.num_vars; ++j)
         if (obj_grad_supp_[j])
-          svw.Write(VPerm(j), c[j]);
+          svw.Write(VPerm(j), c ? c[j] : 0.0);
     }
   }
 
@@ -378,9 +378,11 @@ class NLFeeder2_Easy
 
   void FillObjNonzeros() {
     obj_grad_supp_.resize(NLME().NumCols());
-    // Linear part
-    for (auto i=NLME().NumCols(); i--; )
-      obj_grad_supp_[i] = (NLME().ObjCoefficients()[i]);
+    // Linear part -- if provided
+    if (NLME().ObjCoefficients()) {
+      for (auto i=NLME().NumCols(); i--; )
+        obj_grad_supp_[i] = (NLME().ObjCoefficients()[i]);
+    }
     // QP part
     auto Q = NLME().Hessian();
     if (Q.num_nz_) {