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+/* $Id: CoinPresolveUseless.hpp 1566 2012-11-29 19:33:56Z lou $ */
+// Copyright (C) 2002, International Business Machines
+// Corporation and others. All Rights Reserved.
+// This code is licensed under the terms of the Eclipse Public License (EPL).
+
+#ifndef CoinPresolveUseless_H
+#define CoinPresolveUseless_H
+#define USELESS 20
+
+class useless_constraint_action : public CoinPresolveAction {
+ struct action {
+ double rlo;
+ double rup;
+ const int *rowcols;
+ const double *rowels;
+ int row;
+ int ninrow;
+ };
+
+ const int nactions_;
+ const action *const actions_;
+
+ useless_constraint_action(int nactions,
+ const action *actions,
+ const CoinPresolveAction *next);
+
+ public:
+ const char *name() const;
+
+ // These rows are asserted to be useless,
+ // that is, given a solution the row activity
+ // must be in range.
+ static const CoinPresolveAction *presolve(CoinPresolveMatrix * prob,
+ const int *useless_rows,
+ int nuseless_rows,
+ const CoinPresolveAction *next);
+
+ void postsolve(CoinPostsolveMatrix *prob) const;
+
+ virtual ~useless_constraint_action();
+
+};
+
+/*! \relates useless_constraint_action
+ \brief Scan constraints looking for useless constraints
+
+ A front end to identify useless constraints and hand them to
+ useless_constraint_action::presolve() for processing.
+
+ In a bit more detail, the routine implements a greedy algorithm that
+ identifies a set of necessary constraints. A constraint is necessary if it
+ implies a tighter bound on a variable than the original column bound. These
+ tighter column bounds are then used to calculate row activity and identify
+ constraints that are useless given the presence of the necessary
+ constraints.
+*/
+
+const CoinPresolveAction *testRedundant(CoinPresolveMatrix *prob,
+ const CoinPresolveAction *next) ;
+
+
+
+#endif