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| ** This file is part of the QtGui module of the Qt Toolkit. |
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| ** GNU General Public License Usage |
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| ****************************************************************************/ |
| |
| #ifndef QSIMPLEX_P_H |
| #define QSIMPLEX_P_H |
| |
| // |
| // W A R N I N G |
| // ------------- |
| // |
| // This file is not part of the Qt API. It exists purely as an |
| // implementation detail. This header file may change from version to |
| // version without notice, or even be removed. |
| // |
| // We mean it. |
| // |
| |
| #include <QtCore/qhash.h> |
| #include <QtCore/qpair.h> |
| |
| QT_BEGIN_NAMESPACE |
| |
| struct QSimplexVariable |
| { |
| QSimplexVariable() : result(0), index(0) {} |
| |
| qreal result; |
| int index; |
| }; |
| |
| |
| /*! |
| \internal |
| |
| Representation of a LP constraint like: |
| |
| (c1 * X1) + (c2 * X2) + ... = K |
| or <= K |
| or >= K |
| |
| Where (ci, Xi) are the pairs in "variables" and K the real "constant". |
| */ |
| struct QSimplexConstraint |
| { |
| QSimplexConstraint() : constant(0), ratio(Equal), artificial(0) {} |
| |
| enum Ratio { |
| LessOrEqual = 0, |
| Equal, |
| MoreOrEqual |
| }; |
| |
| QHash<QSimplexVariable *, qreal> variables; |
| qreal constant; |
| Ratio ratio; |
| |
| QPair<QSimplexVariable *, qreal> helper; |
| QSimplexVariable * artificial; |
| |
| void invert(); |
| |
| bool isSatisfied() { |
| qreal leftHandSide(0); |
| |
| QHash<QSimplexVariable *, qreal>::const_iterator iter; |
| for (iter = variables.constBegin(); iter != variables.constEnd(); ++iter) { |
| leftHandSide += iter.value() * iter.key()->result; |
| } |
| |
| Q_ASSERT(constant > 0 || qFuzzyCompare(1, 1 + constant)); |
| |
| if ((leftHandSide == constant) || qAbs(leftHandSide - constant) < 0.0000001) |
| return true; |
| |
| switch (ratio) { |
| case LessOrEqual: |
| return leftHandSide < constant; |
| case MoreOrEqual: |
| return leftHandSide > constant; |
| default: |
| return false; |
| } |
| } |
| |
| #ifdef QT_DEBUG |
| QString toString() { |
| QString result; |
| result += QString::fromAscii("-- QSimplexConstraint %1 --").arg(quintptr(this), 0, 16); |
| |
| QHash<QSimplexVariable *, qreal>::const_iterator iter; |
| for (iter = variables.constBegin(); iter != variables.constEnd(); ++iter) { |
| result += QString::fromAscii(" %1 x %2").arg(iter.value()).arg(quintptr(iter.key()), 0, 16); |
| } |
| |
| switch (ratio) { |
| case LessOrEqual: |
| result += QString::fromAscii(" (less) <= %1").arg(constant); |
| break; |
| case MoreOrEqual: |
| result += QString::fromAscii(" (more) >= %1").arg(constant); |
| break; |
| default: |
| result += QString::fromAscii(" (eqal) == %1").arg(constant); |
| } |
| |
| return result; |
| } |
| #endif |
| }; |
| |
| class QSimplex |
| { |
| public: |
| QSimplex(); |
| virtual ~QSimplex(); |
| |
| qreal solveMin(); |
| qreal solveMax(); |
| |
| bool setConstraints(const QList<QSimplexConstraint *> constraints); |
| void setObjective(QSimplexConstraint *objective); |
| |
| void dumpMatrix(); |
| |
| private: |
| // Matrix handling |
| qreal valueAt(int row, int column); |
| void setValueAt(int row, int column, qreal value); |
| void clearRow(int rowIndex); |
| void clearColumns(int first, int last); |
| void combineRows(int toIndex, int fromIndex, qreal factor); |
| |
| // Simplex |
| bool simplifyConstraints(QList<QSimplexConstraint *> *constraints); |
| int findPivotColumn(); |
| int pivotRowForColumn(int column); |
| void reducedRowEchelon(); |
| bool iterate(); |
| |
| // Helpers |
| void clearDataStructures(); |
| void solveMaxHelper(); |
| enum solverFactor { Minimum = -1, Maximum = 1 }; |
| qreal solver(solverFactor factor); |
| void collectResults(); |
| |
| QList<QSimplexConstraint *> constraints; |
| QList<QSimplexVariable *> variables; |
| QSimplexConstraint *objective; |
| |
| int rows; |
| int columns; |
| int firstArtificial; |
| |
| qreal *matrix; |
| }; |
| |
| inline qreal QSimplex::valueAt(int rowIndex, int columnIndex) |
| { |
| return matrix[rowIndex * columns + columnIndex]; |
| } |
| |
| inline void QSimplex::setValueAt(int rowIndex, int columnIndex, qreal value) |
| { |
| matrix[rowIndex * columns + columnIndex] = value; |
| } |
| |
| QT_END_NAMESPACE |
| |
| #endif // QSIMPLEX_P_H |