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Use a TreeSet instead of an ArrayList when dropping columns after phase 1 of the simplex solver to improve performance. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1367227 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Thomas Neidhart 2012-07-30 19:07:05 +00:00
parent ebc0d3d309
commit 107d7f3ea8
1 changed files with 15 additions and 12 deletions
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9
src/main/java/org/apache/commons/math3/optimization/linear/SimplexTableau.java
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@ -26,6 +26,7 @@ import java.util.Collection;
import java.util.HashSet; import java.util.HashSet;
import java.util.List; import java.util.List;
import java.util.Set; import java.util.Set;
import java.util.TreeSet;
import org.apache.commons.math3.linear.Array2DRowRealMatrix; import org.apache.commons.math3.linear.Array2DRowRealMatrix;
import org.apache.commons.math3.linear.MatrixUtils; import org.apache.commons.math3.linear.MatrixUtils;
@ -333,7 +334,7 @@ class SimplexTableau implements Serializable {
return; return;
} }
List<Integer> columnsToDrop = new ArrayList<Integer>(); Set<Integer> columnsToDrop = new TreeSet<Integer>();
columnsToDrop.add(0); columnsToDrop.add(0);
// positive cost non-artificial variables // positive cost non-artificial variables
@ -362,8 +363,10 @@ class SimplexTableau implements Serializable {
} }
} }
for (int i = columnsToDrop.size() - 1; i >= 0; i--) { // remove the columns in reverse order so the indices are correct
columnLabels.remove((int) columnsToDrop.get(i)); Integer[] drop = columnsToDrop.toArray(new Integer[columnsToDrop.size()]);
for (int i = drop.length - 1; i >= 0; i--) {
columnLabels.remove((int) drop[i]);
} }
this.tableau = new Array2DRowRealMatrix(matrix); this.tableau = new Array2DRowRealMatrix(matrix);