The entire row should be divided when initially making a column basic

Failing to do so will alter the row's meaning if the nonzero value in the
column is anything else than 1.0.

diff --git a/source/layout.cpp b/source/layout.cpp
index d3d015f7305c7ddb70a024c4884ee88cbf3711f2..ba726f7ccbc5b88e29534625cc77b1de026fd1bb 100644 (file)
--- a/source/layout.cpp
+++ b/source/layout.cpp
@@ -497,11 +497,12 @@ void Layout::LinearProgram::prepare_columns()
        /* See if any variables are already basic.  A basic variable must only have
        a nonzero coefficient on one row, and its product with the constant column
        must not be negative.  Only one variable can be basic for any given row. */
-       vector<float> basic_coeff(n_rows, 0.0f);
+       vector<float> obj_coeff(n_rows, 0.0f);
+       vector<float> row_coeff(n_rows, 1.0f);
        const vector<float> &constants = columns.back().values;
        for(vector<Column>::iterator i=columns.begin(); i!=columns.end(); ++i)
        {
-               if(i->values.size()>=2 && i->values.back()!=0.0f && (constants.size()<i->values.size() || i->values.back()*constants[i->values.size()-1]>=0.0f) && basic_coeff[i->values.size()-1]==0.0f)
+               if(i->values.size()>=2 && i->values.back()!=0.0f && (constants.size()<i->values.size() || i->values.back()*constants[i->values.size()-1]>=0.0f) && obj_coeff[i->values.size()-1]==0.0f)
                {
                        bool basic = true;
                        for(unsigned j=1; (basic && j+1<i->values.size()); ++j)
@@ -509,7 +510,8 @@ void Layout::LinearProgram::prepare_columns()
                        if(basic)
                        {
                                i->basic = i->values.size()-1;
-                               basic_coeff[i->basic] = -i->values.front()/i->values.back();
+                               row_coeff[i->basic] = 1.0f/i->values.back();
+                               obj_coeff[i->basic] = -i->values.front();
                                i->values.clear();
                        }
                }
@@ -520,7 +522,10 @@ void Layout::LinearProgram::prepare_columns()
                if(!i->values.empty())
                {
                        for(unsigned j=0; j<i->values.size(); ++j)
-                               i->values.front() += basic_coeff[j]*i->values[j];
+                       {
+                               i->values[j] *= row_coeff[j];
+                               i->values.front() += obj_coeff[j]*i->values[j];
+                       }
                }
 }