List of usage examples for org.apache.commons.math3.linear FieldVector getEntry
T getEntry(int index) throws OutOfRangeException;
From source file:controller.VisLP.java
/** * Draw the linear constraints of an {@code LP} and color * it's feasible region in a given {@code CCSystem}. * //from ww w . j ava2 s . c o m * @param cs * a {@code CCSystem}. * @param lp * a {@code LP}. */ static void drawLP(CCSystem cs, LP lp) { cs.clear(); /* Don't draw the LP if it is not in two variables */ if (lp == null || lp.getNoBasic() != 2) { cs.setVisibleAxes(false); return; } cs.setVisibleAxes(true); CCSLine line; FieldMatrix<BigFraction> cons = lp.getConstraints(); cons = checkForBounds(cons); /* Draw all constraints as lines, except hidden bounded constraint */ for (int i = 0; i < cons.getRowDimension() - 1; i++) { line = new CCSLine(cons.getEntry(i, 0).doubleValue(), cons.getEntry(i, 1).doubleValue(), cons.getEntry(i, 2).doubleValue(), Color.gray); cs.addLine(line); } Point2D[] fpoints = getFeasibleIntersections(cons); /* * Move the center of the coordinate system * to the center of the feasible region. */ if (readScope) { scopeArea(cs, fpoints, true); readScope = false; } if (feasScope && lp.feasible(false)) { scopeArea(cs, fpoints, false); feasScope = false; } /* If there is no feasible region there is no need to try to color it */ if (fpoints.length == 0) return; /* Draw all feasible solutions as points */ Point2D[] pconv = convex(fpoints); for (Point2D p2d : pconv) { CCSPoint ccsp = new CCSPoint(p2d.getX(), p2d.getY()); if (!unb.contains(p2d)) cs.addPoint(ccsp); } /* Color the region depending on whether it is unbounded or not. */ if (unb.size() == 0) { cs.addPolygon(new CCSPolygon(pconv, Color.pink, true)); } else if (unb.size() == 1) { GradientPaint gp = new GradientPaint(pconv[0], Color.pink, unb.get(0), cs.getBackground()); cs.addPolygon(new CCSPolygon(pconv, gp, true)); } else { Point2D p1 = unb.get(0); Point2D p2 = unb.get(1); double xavg = (p1.getX() + p2.getX()) / 2.0; double yavg = (p1.getY() + p2.getY()) / 2.0; /* * Move the end point of the gradient further away from the * polygon edge to make the end of the gradient look less sudden. */ xavg *= 0.9; yavg *= 0.9; Point2D pavg = new Point2D.Double(xavg, yavg); /* Fade into the background color */ GradientPaint gp = new GradientPaint(pconv[0], Color.pink, pavg, cs.getBackground()); cs.addPolygon(new CCSPolygon(pconv, gp, true)); } /* Draw the current objective function */ FieldVector<BigFraction> obj = lp.getObjFunction(); line = new CCSLine(obj.getEntry(0).doubleValue(), obj.getEntry(1).doubleValue(), lp.objVal().doubleValue(), Color.red); cs.addLine(line); /* Draw the current basic solution as a point. */ BigFraction[] point = lp.point(); cs.addPoint(new CCSPoint(point[0].doubleValue(), point[1].doubleValue(), Color.red, true)); }
From source file:model.LP.java
public static BigFraction getMinValue(FieldVector<BigFraction> bf) { BigFraction min = bf.getEntry(0); for (int i = 1; i < bf.getDimension(); i++) { BigFraction val = bf.getEntry(i); if (val.compareTo(min) < 0) { min = val; }/*ww w . java2 s . c o m*/ } return min; }
From source file:controller.VisLP.java
private static boolean feasible(Point2D p2d, FieldMatrix<BigFraction> N, FieldVector<BigFraction> b) { double x = p2d.getX(); double y = p2d.getY(); for (int j = 0; j < N.getRowDimension(); j++) { float nx = N.getEntry(j, 0).floatValue(); float ny = N.getEntry(j, 1).floatValue(); float val = (float) (nx * x + ny * y); if (val > b.getEntry(j).floatValue()) return false; }/*from www.j a va 2 s . c om*/ return true; }
From source file:controller.VisLP.java
private static Point2D[] getFeasibleIntersections(FieldMatrix<BigFraction> cons) { FieldMatrix<BigFraction> N = cons.getSubMatrix(0, cons.getRowDimension() - 1, 0, cons.getColumnDimension() - 2); FieldVector<BigFraction> b = cons.getColumnVector(cons.getColumnDimension() - 1); HashSet<Point2D> points = new HashSet<Point2D>(); unb = new ArrayList<Point2D>(); /* Find all intersections */ for (int i = 0; i < N.getRowDimension(); i++) { for (int j = 0; j < N.getRowDimension(); j++) { if (i == j) continue; FieldMatrix<BigFraction> line1 = N.getRowMatrix(i); FieldMatrix<BigFraction> line2 = N.getRowMatrix(j); BigFraction[] bval = new BigFraction[] { b.getEntry(i), b.getEntry(j) }; FieldVector<BigFraction> bsys = new ArrayFieldVector<BigFraction>(bval); FieldMatrix<BigFraction> sys = LP.addBlock(line1, line2, LP.UNDER); try { FieldVector<BigFraction> point = new FieldLUDecomposition<BigFraction>(sys).getSolver() .getInverse().operate(bsys); double x = point.getEntry(0).doubleValue(); double y = point.getEntry(1).doubleValue(); Point2D p2d = new Point2D.Double(x, y); /* Only add feasible points */ if (feasible(p2d, N, b)) { if (i >= N.getRowDimension() - 1) unb.add(p2d);//from ww w. j a v a 2 s . c om points.add(p2d); } } catch (IllegalArgumentException e) { /* * Two lines that don't intersect forms an invertible * matrix. Skip these points. */ } } } return points.toArray(new Point2D[0]); }
From source file:model.LP.java
/** * Find an entering variable index according * to the largest coefficients rule.//from w ww .j a va2s .c o m * * @param dual * If true, find an entering variable index for the dual dictionary. * Otherwise, find one for the primal dictionary. * @return * An entering variable index. */ private int entering(boolean dual) { String e = "Incumbent basic solution is optimal."; String e2 = String.format("Incumbent basic solution is %s infeasible", dual ? "dually" : "primal"); if (optimal(dual)) throw new RuntimeException(e); if (!feasible(dual)) throw new RuntimeException(e2); FieldVector<BigFraction> check = dual ? b_ : c_; BigFraction min = BigFraction.ZERO; int index = -1; for (int i = 0; i < check.getDimension(); i++) { BigFraction val = check.getEntry(i); if (val.compareTo(min) < 0) { min = val; index = i; } } return index; }
From source file:model.LP.java
/** * Do one iteration of the simplex method. * * @param entering//ww w .j a va 2 s . co m * Index of variable to enter the basis. * @param leaving * Index of variable to leave the basis. * @return * A linear program after one iteration. */ public LP pivot(int entering, int leaving) { FieldMatrix<BigFraction> bin = new FieldLUDecomposition<BigFraction>(B_).getSolver().getInverse() .multiply(N_); // Step 1: Check for optimpivality // Step 2: Select entering variable. // Naive method. Does not check for optimality. Assumes feasibility. // Entering variable is given. // Step 3: Compute primal step direction. FieldVector<BigFraction> ej = new ArrayFieldVector<BigFraction>(bin.getColumnDimension(), BigFraction.ZERO); ej.setEntry(entering, BigFraction.ONE); FieldVector<BigFraction> psd = bin.operate(ej); // Step 4: Compute primal step length. // Step 5: Select leaving variable. // Leaving variable is given. BigFraction t = b_.getEntry(leaving).divide(psd.getEntry(leaving)); // Step 6: Compute dual step direction. FieldVector<BigFraction> ei = new ArrayFieldVector<BigFraction>(bin.getRowDimension(), BigFraction.ZERO); ei.setEntry(leaving, BigFraction.ONE); FieldVector<BigFraction> dsd = bin.transpose().scalarMultiply(BigFraction.MINUS_ONE).operate(ei); // Step 7: Compute dual step length. BigFraction s = c_.getEntry(entering).divide(dsd.getEntry(entering)); // Step 8: Update current primal and dual solutions. FieldVector<BigFraction> nb_ = b_.subtract(psd.mapMultiply(t)); nb_.setEntry(leaving, t); FieldVector<BigFraction> nc_ = c_.subtract(dsd.mapMultiply(s)); nc_.setEntry(entering, s); // Step 9: Update basis. FieldVector<BigFraction> temp = B_.getColumnVector(leaving); FieldMatrix<BigFraction> nB_ = B_.copy(); nB_.setColumn(leaving, N_.getColumn(entering)); FieldMatrix<BigFraction> nN_ = N_.copy(); nN_.setColumnVector(entering, temp); int[] nBi = Bi.clone(); int[] nNi = Ni.clone(); nBi[leaving] = Ni[entering]; nNi[entering] = Bi[leaving]; return new LP(B, N, b, c, nB_, nN_, nb_, nc_, x, nBi, nNi); }
From source file:model.LP.java
public LP reinstate() { FieldVector<BigFraction> nc_ = new ArrayFieldVector<BigFraction>(c_.getDimension(), BigFraction.ZERO); FieldMatrix<BigFraction> bin = new FieldLUDecomposition<BigFraction>(B_).getSolver().getInverse() .multiply(N_);//from w ww. j a va 2 s . c om for (int i = 0; i < Bi.length; i++) { int k = Bi[i]; if (k < Ni.length) { for (int j = 0; j < Ni.length; j++) { BigFraction bf = c.getEntry(k).multiply(bin.getEntry(i, j)); nc_.setEntry(j, nc_.getEntry(j).add(bf)); } } } for (int i = 0; i < Ni.length; i++) { int k = Ni[i]; if (k < Ni.length) { nc_.setEntry(i, nc_.getEntry(i).subtract(c.getEntry(i))); } } return new LP(B, N, b, c, B_, N_, b_, nc_, x, Bi, Ni); }
From source file:model.LP.java
/** * Find a leaving variable index that is the most * bounding on the given entering variable index. * * @param entering//from www. java 2s . c o m * an entering variable index. * @param dual * If true, find a leaving variable index for the dual dictionary. * Otherwise, find one for the primal dictionary. * @return * A leaving variable index. */ private int leaving(int entering, boolean dual) { FieldVector<BigFraction> check; FieldVector<BigFraction> sd; FieldMatrix<BigFraction> bin = new FieldLUDecomposition<BigFraction>(B_).getSolver().getInverse() .multiply(N_); if (dual) { check = c_; FieldVector<BigFraction> unit = new ArrayFieldVector<BigFraction>(bin.getRowDimension(), BigFraction.ZERO); unit.setEntry(entering, BigFraction.ONE); sd = bin.transpose().scalarMultiply(BigFraction.MINUS_ONE).operate(unit); } else { check = b_; FieldVector<BigFraction> unit = new ArrayFieldVector<BigFraction>(bin.getColumnDimension(), BigFraction.ZERO); unit.setEntry(entering, BigFraction.ONE); sd = bin.operate(unit); } boolean unbounded = true; int index = -1; /* Check for unboundedness and find first non-zero element in check */ for (int i = 0; i < sd.getDimension(); i++) { if (!check.getEntry(i).equals(BigFraction.ZERO) && index == -1) { index = i; } if (sd.getEntry(i).compareTo(BigFraction.ZERO) > 0) { unbounded = false; } } String e = "Program is unbounded."; if (unbounded) throw new RuntimeException(e); /* Set temporarily max value as ratio of the first divisible pair. */ BigFraction max = sd.getEntry(index).divide(check.getEntry(index)); for (int i = 0; i < sd.getDimension(); i++) { BigFraction num = sd.getEntry(i); BigFraction denom = check.getEntry(i); if (!denom.equals(BigFraction.ZERO)) { BigFraction val = num.divide(denom); if (val.compareTo(max) > 0) { max = val; index = i; } } else { if (num.compareTo(BigFraction.ZERO) > 0) return i; } } return index; }
From source file:org.rhwlab.BHCnotused.GaussianGIWPrior.java
private void vectorAsString(FieldVector v, StringBuilder builder) { boolean first = true; builder.append("("); for (int i = 0; i < v.getDimension(); ++i) { if (!first) { builder.append(String.format(",%d", ((Dfp) v.getEntry(i)).intValue())); } else {/* www . j a v a 2 s . c om*/ builder.append(String.format("%d", ((Dfp) v.getEntry(i)).intValue())); } first = false; } builder.append(")"); }