Changeset 1431:ad44b1dd8013 in lemon-0.x

Timestamp:

05/20/05 11:31:25 (19 years ago)

Author:

athos

Branch:

default

Phase:

public

Convert:

svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@1905

Message:

Added function _setCoeff().

Location:

src/lemon

Files:

• lp_base.h (modified) (1 diff)
• lp_cplex.cc (modified) (1 diff)
• lp_cplex.h (modified) (1 diff)
• lp_glpk.cc (modified) (1 diff)
• lp_glpk.h (modified) (1 diff)
• lp_skeleton.cc (modified) (1 diff)
• lp_skeleton.h (modified) (1 diff)

src/lemon/lp_base.h

@@ -430 +430 @@
                                int  const * indices, 
                                Value  const * values ) = 0;
+    virtual void _setCoeff(int row, int col, Value value) = 0;
     virtual void _setColLowerBound(int i, Value value) = 0;
     virtual void _setColUpperBound(int i, Value value) = 0;

src/lemon/lp_cplex.cc

@@ -132 +132 @@
   }
   
+  void LpCplex::_setCoeff(int row, int col, Value value) 
+  {
+    CPXchgcoef (env, lp, row, col, value);
+  }
+
   void LpCplex::_setColLowerBound(int i, Value value)
   {

src/lemon/lp_cplex.h

@@ -64 +64 @@
                                const int   * indices, 
                                const Value   * values);
+    virtual void _setCoeff(int row, int col, Value value);
     virtual void _setColLowerBound(int i, Value value);
     virtual void _setColUpperBound(int i, Value value);

src/lemon/lp_glpk.cc

@@ -88 +88 @@
                     const_cast<Value * >(values));
   }
-  
+
+
+  void LpGlpk::_setCoeff(int row, int col, Value value) 
+  {
+    ///FIXME Of course this is not efficient at all, but GLPK knows not more.
+    // First approach: get one row, apply changes and set it again
+    //(one idea to improve this: maybe it is better to do this with 1 coloumn)
+    
+    int mem_length=2+lpx_get_num_cols(lp);
+    int* indices = new int[mem_length];
+    Value* values = new Value[mem_length];
+    
+
+    int length=lpx_get_mat_row(lp, row, indices, values);
+
+    //The following code does not suppose that the elements of the array indices are sorted
+    int i=1;
+    bool found=false;
+    while (i <= length && !found){
+      if (indices[i]==col){
+        found = true;
+        values[i]=value;
+      }
+      ++i;
+    }
+    if (!found){
+      ++length;
+      indices[length]=col;
+      values[length]=value;
+    }
+    
+    lpx_set_mat_row(lp, row, length, indices, values);
+    delete [] indices;
+    delete [] values;
+    
+  }
+
   void LpGlpk::_setColLowerBound(int i, Value lo)
   {

src/lemon/lp_glpk.h

@@ -59 +59 @@
                                const int   * indices, 
                                const Value   * values);
+    virtual void _setCoeff(int row, int col, Value value);
     virtual void _setColLowerBound(int i, Value value);
     virtual void _setColUpperBound(int i, Value value);

src/lemon/lp_skeleton.cc

@@ -57 +57 @@
   {
   }
-  
+
+  void LpSkeleton::_setCoeff(int, int, Value )
+  {
+  }
+
+
   void LpSkeleton::_setColLowerBound(int, Value)
   {

src/lemon/lp_skeleton.h

@@ -55 +55 @@
                                Value  const * values );
     
-    /// \e
+    /// Set one element of the coefficient matrix
+    virtual void _setCoeff(int row, int col, Value value);
 
     /// The lower bound of a variable (column) have to be given by an