Java Code Examples for org.apache.commons.math.util.MathUtils#compareTo()

/**
 * Returns the row with the minimum ratio as given by the minimum ratio test (MRT).
 * @param tableau simple tableau for the problem
 * @param col the column to test the ratio of.  See {@link #getPivotColumn(SimplexTableau)}
 * @return row with the minimum ratio
 */
private Integer getPivotRow(final int col, final SimplexTableau tableau) {
    double minRatio = Double.MAX_VALUE;
    Integer minRatioPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getHeight(); i++) {
        final double rhs = tableau.getEntry(i, tableau.getWidth() - 1);
        final double entry = tableau.getEntry(i, col);
        if (MathUtils.compareTo(entry, 0, epsilon) > 0) {
            final double ratio = rhs / entry;
            if (ratio < minRatio) {
                minRatio = ratio;
                minRatioPos = i; 
            }
        }
    }
    return minRatioPos;
}
 

/**
 * Returns the row with the minimum ratio as given by the minimum ratio test (MRT).
 * @param tableau simple tableau for the problem
 * @param col the column to test the ratio of.  See {@link #getPivotColumn(SimplexTableau)}
 * @return row with the minimum ratio
 */
private Integer getPivotRow(final int col, final SimplexTableau tableau) {
    double minRatio = Double.MAX_VALUE;
    Integer minRatioPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getHeight(); i++) {
        final double rhs = tableau.getEntry(i, tableau.getWidth() - 1);
        final double entry = tableau.getEntry(i, col);
        if (MathUtils.compareTo(entry, 0, epsilon) >= 0) {
            final double ratio = rhs / entry;
            if (ratio < minRatio) {
                minRatio = ratio;
                minRatioPos = i; 
            }
        }
    }
    return minRatioPos;
}
 

/**
 * Returns the row with the minimum ratio as given by the minimum ratio test (MRT).
 * @param tableau simple tableau for the problem
 * @param col the column to test the ratio of.  See {@link #getPivotColumn(SimplexTableau)}
 * @return row with the minimum ratio
 */
private Integer getPivotRow(final int col, final SimplexTableau tableau) {
    double minRatio = Double.MAX_VALUE;
    Integer minRatioPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getHeight(); i++) {
        final double rhs = tableau.getEntry(i, tableau.getWidth() - 1);
        final double entry = tableau.getEntry(i, col);
        if (MathUtils.compareTo(entry, 0, epsilon) > 0) {
            final double ratio = rhs / entry;
            if (ratio < minRatio) {
                minRatio = ratio;
                minRatioPos = i; 
            }
        }
    }
    return minRatioPos;
}
 

/**
 * Returns the row with the minimum ratio as given by the minimum ratio test (MRT).
 * @param tableau simple tableau for the problem
 * @param col the column to test the ratio of.  See {@link #getPivotColumn()}
 * @return row with the minimum ratio
 */
private Integer getPivotRow(final int col, final SimplexTableau tableau) {
    double minRatio = Double.MAX_VALUE;
    Integer minRatioPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getHeight(); i++) {
        double rhs = tableau.getEntry(i, tableau.getWidth() - 1);
        if (MathUtils.compareTo(tableau.getEntry(i, col), 0, epsilon) >= 0) {
            double ratio = rhs / tableau.getEntry(i, col);
            if (ratio < minRatio) {
                minRatio = ratio;
                minRatioPos = i; 
            }
        }
    }
    return minRatioPos;
}
 

/**
 * Checks whether Phase 1 is solved.
 * @param tableau simple tableau for the problem
 * @return whether Phase 1 is solved
 */
private boolean isPhase1Solved(final SimplexTableau tableau) {
    if (tableau.getNumArtificialVariables() == 0) {
        return true;
    }
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), 0, epsilon) < 0) {
            return false;
        }
    }
    return true;
}
 

/**
 * Returns whether the problem is at an optimal state.
 * @return whether the model has been solved
 */
boolean isOptimal() {
    for (int i = getNumObjectiveFunctions(); i < getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), 0, epsilon) < 0) {
            return false;
        }
    }
    return true;
}
 

/**
 * Returns the column with the most negative coefficient in the objective function row.
 * @param tableau simple tableau for the problem
 * @return column with the most negative coefficient
 */
private Integer getPivotColumn(SimplexTableau tableau) {
    double minValue = 0;
    Integer minPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), minValue, epsilon) < 0) {
            minValue = tableau.getEntry(0, i);
            minPos = i;
        }
    }
    return minPos;
}
 

/**
 * Returns the column with the most negative coefficient in the objective function row.
 * @param tableau simple tableau for the problem
 * @return column with the most negative coefficient
 */
private Integer getPivotColumn(SimplexTableau tableau) {
    double minValue = 0;
    Integer minPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), minValue, epsilon) < 0) {
            minValue = tableau.getEntry(0, i);
            minPos = i;
        }
    }
    return minPos;
}
 

/**
 * Returns the column with the most negative coefficient in the objective function row.
 * @param tableau simple tableau for the problem
 * @return column with the most negative coefficient
 */
private Integer getPivotColumn(SimplexTableau tableau) {
    double minValue = 0;
    Integer minPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), minValue, epsilon) < 0) {
            minValue = tableau.getEntry(0, i);
            minPos = i;
        }
    }
    return minPos;
}
 

/**
 * Returns whether the problem is at an optimal state.
 * @param tableau simple tableau for the problem
 * @return whether the model has been solved
 */
public boolean isOptimal(final SimplexTableau tableau) {
    if (tableau.getNumArtificialVariables() > 0) {
        return false;
    }
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), 0, epsilon) < 0) {
            return false;
        }
    }
    return true;
}
 

/**
 * Returns whether the problem is at an optimal state.
 * @param tableau simple tableau for the problem
 * @return whether the model has been solved
 */
public boolean isOptimal(final SimplexTableau tableau) {
    if (tableau.getNumArtificialVariables() > 0) {
        return false;
    }
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), 0, epsilon) < 0) {
            return false;
        }
    }
    return true;
}
 

/**
 * Returns the column with the most negative coefficient in the objective function row.
 * @param tableau simple tableau for the problem
 * @return column with the most negative coefficient
 */
private Integer getPivotColumn(SimplexTableau tableau) {
    double minValue = 0;
    Integer minPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), minValue, epsilon) < 0) {
            minValue = tableau.getEntry(0, i);
            minPos = i;
        }
    }
    return minPos;
}
 

/**
 * Returns the column with the most negative coefficient in the objective function row.
 * @param tableau simple tableau for the problem
 * @return column with the most negative coefficient
 */
private Integer getPivotColumn(SimplexTableau tableau) {
    double minValue = 0;
    Integer minPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), minValue, epsilon) < 0) {
            minValue = tableau.getEntry(0, i);
            minPos = i;
        }
    }
    return minPos;
}
 

/**
 * Returns the row with the minimum ratio as given by the minimum ratio test (MRT).
 * @param tableau simple tableau for the problem
 * @param col the column to test the ratio of.  See {@link #getPivotColumn(SimplexTableau)}
 * @return row with the minimum ratio
 */
private Integer getPivotRow(SimplexTableau tableau, final int col) {
    // create a list of all the rows that tie for the lowest score in the minimum ratio test
    List<Integer> minRatioPositions = new ArrayList<Integer>();
    double minRatio = Double.MAX_VALUE;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getHeight(); i++) {
        final double rhs = tableau.getEntry(i, tableau.getWidth() - 1);
        final double entry = tableau.getEntry(i, col);
        if (MathUtils.compareTo(entry, 0, epsilon) > 0) {
            final double ratio = rhs / entry;
            if (MathUtils.equals(ratio, minRatio, epsilon)) {
                minRatioPositions.add(i);
            } else if (ratio < minRatio) {
                minRatio = ratio;
                minRatioPositions = new ArrayList<Integer>();
                minRatioPositions.add(i);
            }
        }
    }

    if (minRatioPositions.size() == 0) {
      return null;
    } else if (minRatioPositions.size() > 1) {
      // there's a degeneracy as indicated by a tie in the minimum ratio test
      // check if there's an artificial variable that can be forced out of the basis
      for (Integer row : minRatioPositions) {
        for (int i = 0; i < tableau.getNumArtificialVariables(); i++) {
          int column = i + tableau.getArtificialVariableOffset();
          if (MathUtils.equals(tableau.getEntry(row, column), 1, epsilon) &&
              row.equals(tableau.getBasicRow(column))) {
            return row;
          }
        }
      }
    }
    return minRatioPositions.get(0);
}
 

/**
 * Returns whether the problem is at an optimal state.
 * @param tableau simple tableau for the problem
 * @return whether the model has been solved
 */
public boolean isOptimal(final SimplexTableau tableau) {
    if (tableau.getNumArtificialVariables() > 0) {
        return false;
    }
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), 0, epsilon) < 0) {
            return false;
        }
    }
    return true;
}
 

/**
 * Returns whether the problem is at an optimal state.
 * @param tableau simple tableau for the problem
 * @return whether the model has been solved
 */
public boolean isOptimal(final SimplexTableau tableau) {
    if (tableau.getNumArtificialVariables() > 0) {
        return false;
    }
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), 0, epsilon) < 0) {
            return false;
        }
    }
    return true;
}
 

/**
 * Returns the column with the most negative coefficient in the objective function row.
 * @param tableau simple tableau for the problem
 * @return column with the most negative coefficient
 */
private Integer getPivotColumn(SimplexTableau tableau) {
    double minValue = 0;
    Integer minPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
    	//if((org.apache.commons.math.util.MathUtils.compareTo(tableau.getEntry(0, i), 0, epsilon)) < 0){
    	if (MathUtils.compareTo(tableau.getEntry(0, i), minValue, epsilon) < 0) {
            minValue = tableau.getEntry(0, i);
            minPos = i;
        }
    }
    return minPos;
}
 

/**
 * Returns the column with the most negative coefficient in the objective function row.
 * @param tableau simple tableau for the problem
 * @return column with the most negative coefficient
 */
private Integer getPivotColumn(SimplexTableau tableau) {
    double minValue = 0;
    Integer minPos = null;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), minValue, epsilon) < 0) {
            minValue = tableau.getEntry(0, i);
            minPos = i;
        }
    }
    return minPos;
}
 

/**
 * Returns the row with the minimum ratio as given by the minimum ratio test (MRT).
 * @param tableau simple tableau for the problem
 * @param col the column to test the ratio of.  See {@link #getPivotColumn(SimplexTableau)}
 * @return row with the minimum ratio
 */
private Integer getPivotRow(SimplexTableau tableau, final int col) {
    // create a list of all the rows that tie for the lowest score in the minimum ratio test
    List<Integer> minRatioPositions = new ArrayList<Integer>();
    double minRatio = Double.MAX_VALUE;
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getHeight(); i++) {
        final double rhs = tableau.getEntry(i, tableau.getWidth() - 1);
        final double entry = tableau.getEntry(i, col);
        if (MathUtils.compareTo(entry, 0, epsilon) > 0) {
            final double ratio = rhs / entry;
            if (MathUtils.equals(ratio, minRatio, epsilon)) {
                minRatioPositions.add(i);
            } else if (ratio < minRatio) {
                minRatio = ratio;
                minRatioPositions = new ArrayList<Integer>();
                minRatioPositions.add(i);
            }
        }
    }

    if (minRatioPositions.size() == 0) {
      return null;
    } else if (minRatioPositions.size() > 1) {
      // there's a degeneracy as indicated by a tie in the minimum ratio test
      // check if there's an artificial variable that can be forced out of the basis
      for (Integer row : minRatioPositions) {
        for (int i = 0; i < tableau.getNumArtificialVariables(); i++) {
          int column = i + tableau.getArtificialVariableOffset();
          if (MathUtils.equals(tableau.getEntry(row, column), 1, epsilon) &&
              row.equals(tableau.getBasicRow(column))) {
            return row;
          }
        }
      }
    }
    return minRatioPositions.get(0);
}
 

/**
 * Checks whether Phase 1 is solved.
 * @param tableau simple tableau for the problem
 * @return whether Phase 1 is solved
 */
private boolean isPhase1Solved(final SimplexTableau tableau) {
    if (tableau.getNumArtificialVariables() == 0) {
        return true;
    }
    for (int i = tableau.getNumObjectiveFunctions(); i < tableau.getWidth() - 1; i++) {
        if (MathUtils.compareTo(tableau.getEntry(0, i), 0, epsilon) < 0) {
            return false;
        }
    }
    return true;
}