void stepFinished(const GridType& grid, unsigned step, WriterEvent event)
{
avrgTemperature = 0;
CoordBox<2> box = grid.boundingBox();
for (CoordBox<2>::Iterator i = box.begin(); i != box.end(); ++i) {
avrgTemperature += grid.get(*i).temperature;
}
avrgTemperature /= box.dimensions.prod();
std::cout << "averageTemperature(" << step << ") = " << avrgTemperature << "\n";
}
