Method ColoredMatrix

examples/colored-matrix.cpp:359–420

Actual model

  /// Actual model
  ColoredMatrix(const ColoredMatrixOptions& opt0)
    : IntMinimizeScript(opt0),
      opt(opt0), height(opt.height()), width(opt.width()), colors(opt.colors()),
      x(*this, height*width, 1, colors),
      max_color(*this, 1, colors)
  {

    max(*this, x, max_color);

    Matrix<IntVarArray> m(x, width, height);

    // For each pair of columns and rows, the intersections may not be equal.
    if (opt.model() & MODEL_CORNERS) {
      for (int c1 = 0; c1 < width; ++c1) {
        for (int c2 = c1+1; c2 < width; ++c2) {
          for (int r1 = 0; r1 < height; ++r1) {
            for (int r2 = r1+1; r2 < height; ++r2) {
              not_all_equal(IntVarArgs() << m(c1,r1) << m(c1,r2) << m(c2,r1) << m(c2,r2));
            }
          }
        }
      }
    }
    // Given two rows/columns, construct variables representing if
    // the corresponding places are equal (and if so, what value).
    // For the new values, no non-zero value may appear more than
    // once.
    if (opt.model() & MODEL_ROWS) {
      for (int r1 = 0; r1 < height; ++r1) {
        for (int r2 = r1+1; r2 < height; ++r2) {
          no_monochrome_rectangle(m.row(r1), m.row(r2));
        }
      }
    }
    if (opt.model() & MODEL_COLUMNS) {
      for (int c1 = 0; c1 < width; ++c1) {
        for (int c2 = c1+1; c2 < width; ++c2) {
          no_monochrome_rectangle(m.col(c1), m.col(c2));
        }
      }
    }

    // Symmetry breaking constraints.
    {
      // Lexical order for all columns and rows (all are interchangeable)
      if (opt.symmetry() & SYMMETRY_MATRIX) {
        for (int r = 0; r < height-1; ++r) {
          rel(*this, m.row(r), IRT_LE, m.row(r+1));
        }
        for (int c = 0; c < width-1; ++c) {
          rel(*this, m.col(c), IRT_LE, m.col(c+1));
        }
      }

      // Value precedence. Compatible with row/column ordering
      if (opt.symmetry() & SYMMETRY_VALUES) {
        precede(*this, x, IntArgs::create(colors, 1));
      }