Changeset 1099:91a8ee9d088d in lemon-0.x for src/work/marci/lp/expression.h

Timestamp:

01/27/05 18:44:04 (20 years ago)

Author:

marci

Branch:

default

Phase:

public

Convert:

svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@1498

Message:

-=, - operators in expressions

File:

• src/work/marci/lp/expression.h (modified) (6 diffs)

src/work/marci/lp/expression.h

@@ -20 +20 @@
   template <typename _Col, typename _Value>
   class Expr {
-  protected:
+//  protected:
+  public:
     typedef 
     typename std::map<_Col, _Value> Data; 
     Data data;
   public:
+    void simplify() {
+      for (typename Data::iterator i=data.begin(); 
+           i!=data.end(); ++i) {
+        if ((*i).second==0) data.erase(i);
+      }
+    }
     Expr() { }
     Expr(_Col _col) { 
@@ -34 +41 @@
         (*i).second *= _value;
       }
+      simplify();
       return *this;
     }
@@ -46 +54 @@
         }
       }
+      simplify();
+      return *this;
+    }
+    Expr& operator-=(const Expr<_Col, _Value>& expr) {
+      for (typename Data::const_iterator j=expr.data.begin(); 
+           j!=expr.data.end(); ++j) {
+        typename Data::iterator i=data.find((*j).first);
+        if (i==data.end()) {
+          data.insert(std::make_pair((*j).first, -(*j).second));
+        } else {
+          (*i).second+=-(*j).second;
+        }
+      }
+      simplify();
       return *this;
     }
@@ -57 +79 @@
     Expr<_Col, _Value> tmp(_col);
     tmp*=_value;
+    tmp.simplify();
     return tmp;
   }
@@ -65 +88 @@
     Expr<_Col, _Value> tmp(expr);
     tmp*=_value;
+    tmp.simplify();
     return tmp;
   }
@@ -73 +97 @@
     Expr<_Col, _Value> tmp(expr1);
     tmp+=expr2;
+    tmp.simplify();
+    return tmp;
+  }
+
+  template <typename _Col, typename _Value>
+  Expr<_Col, _Value> operator-(const Expr<_Col, _Value>& expr1, 
+                               const Expr<_Col, _Value>& expr2) {
+    Expr<_Col, _Value> tmp(expr1);
+    tmp-=expr2;
+    tmp.simplify();
     return tmp;
   }