Changeset 1431:ad44b1dd8013 in lemon-0.x for src/lemon/lp_glpk.cc

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().

File:

• src/lemon/lp_glpk.cc (modified) (1 diff)

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)
   {