Solution solution = new Solution(start, stop, step);
// map contains derivative and initial value
// <y0, 0.0> , <y1, 0.0> , ... , <z0, 0.5> , <z1, 0.5> , ...
Map<String, Double> map = null;
solution.addResult(y.get(y.size() - 1));
for (double i = start; i < stop; i += step)
{
// add <y0, val>, <y1, val2> ....
map = getMap(y, equation.getFunctionVariable());