Function pos

examples/pentominoes.cpp:881–888

// Symmetry functions
namespace {
  int pos(int h, int w, int h1, int w1) {
    if (!(0 <= h && h < h1) ||
        !(0 <= w && w < w1)) {
      std::cerr << "Cannot place (" << h << "," << w
                << ") on board of size " << h1 << "x" << w1 << std::endl;
    }
    return h * w1 + w;
  }
  template<class CArray, class Array>
  void id(CArray t1, int w1, int h1, Array t2, int& w2, int&h2) {
    w2 = w1; h2 = h1;