MP2NL: Div expression, QP terms as expression #237

Don't linearize quadratics with acc:_expr=1 because we assume any nonlinear solver to accept quadratics; put objective's QP terms into the expression
ampl · Oct 30, 2024 · b54b78e · b54b78e
1 parent 0b32144
commit b54b78e
Show file tree

Hide file tree

Showing 3 changed files with 22 additions and 3 deletions.
diff --git a/include/mp/flat/redef/MIP/mul.h b/include/mp/flat/redef/MIP/mul.h
@@ -30,6 +30,13 @@ class QCConverter_MIP :
 		return !GetMC().IfPassQuadCon();
   }
 
+  /// Skip conversion?
+  bool IfDelayConversion(const ItemType& , int ) {
+    return
+        GetMC().IfPassQuadCon()
+        || GetMC().IfWantNLOutput();     // Assume QuadExpr accepted
+  }
+
   /// Conversion
 	void Convert(const ItemType& qc, int ) {
 		LinearizeQPTerms(qc);

diff --git a/solvers/mp2nl/mp2nlmodelapi.cc b/solvers/mp2nl/mp2nlmodelapi.cc
@@ -221,6 +221,9 @@ MP2NL_Expr MP2NLModelAPI::AddExpression(const SinExpression &expr)
 MP2NL_Expr MP2NLModelAPI::AddExpression(const CosExpression &expr)
 { return AddExpression(expr, ExpressionTypeID::ID_Cos); }
 
+MP2NL_Expr MP2NLModelAPI::AddExpression(const DivExpression &expr)
+{ return AddExpression(expr, ExpressionTypeID::ID_Div); }
+
 
 void MP2NLModelAPI::FinishProblemModificationPhase() { }
 
@@ -752,6 +755,8 @@ void MP2NLModelAPI::FeedOpcode(Expr expr, ExprWriter& ew) {
     HANDLE_OPCODE_CASE_1_ARG(Sin, SIN, FdArgs)
     HANDLE_OPCODE_CASE_1_ARG(Cos, COS, FdArgs)
 
+    HANDLE_OPCODE_CASE_2_ARG(Div, DIV, FdArgs)
+
   default:
     MP_RAISE("MP2NL: unknown expression type");
   }

diff --git a/solvers/mp2nl/mp2nlmodelapi.h b/solvers/mp2nl/mp2nlmodelapi.h
@@ -94,8 +94,9 @@ class MP2NLModelAPI
   void AddVariables(const VarArrayDef& vad);
   void SetLinearObjective( int iobj, const LinearObjective& lo );
   /// Whether accepting quadratic objectives:
-  /// 0 - no, 1 - convex, 2 - nonconvex
-	static int AcceptsQuadObj() { return 2; }
+  /// 0 - no, 1 - convex, 2 - nonconvex.
+  /// Return 0 because the QP terms go into expression
+  static int AcceptsQuadObj() { return 0; }
   void SetQuadraticObjective(int iobj, const QuadraticObjective& qo);
   /// Whether accepts NLObjective.
   static int AcceptsNLObj() { return 1; }
@@ -414,6 +415,9 @@ class MP2NLModelAPI
   ACCEPT_EXPRESSION(CosExpression, Recommended)
   Expr AddExpression(const CosExpression& );
 
+  ACCEPT_EXPRESSION(DivExpression, Recommended)
+  Expr AddExpression(const DivExpression& );
+
   // TODO Div; PowVarVar;
 
 
@@ -1110,7 +1114,9 @@ class MP2NLModelAPI
     ID_Log,
     ID_Pow,
     ID_Sin,
-    ID_Cos
+    ID_Cos,
+
+    ID_Div
   };
 
 
@@ -1287,6 +1293,7 @@ class MP2NLModelAPI
   CREATE_EXPRESSION_DISPATCHER(Sin)
   CREATE_EXPRESSION_DISPATCHER(Cos)
 
+  CREATE_EXPRESSION_DISPATCHER(Div)
 
   /// Constraint/objective/expression info.
   /// We rely on the pointers staying valid.