From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 29 May 2013 19:12:11 +0000 (+0300)
Subject: The entire row should be divided when initially making a column basic
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=b15a68afd1d1c36cb953bc29bf234413991c911d;p=libs%2Fgltk.git

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 d3d015f..ba726f7 100644
--- 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];
+			}
 		}
 }