//processing equations
int i;
for (i = 0; i < equations.length; ++i) {
Expression eq = equations[i];
//iterating over the whole equation
FromChildToParentIterator iterator = new FromChildToParentIterator(eq);
Tensor t;
while ((t = iterator.next()) != null) {
if (!(t instanceof Product) || t.getIndices().size() == 0)
continue;
//scalars content
Tensor[] scalars = ((Product) t).getContent().getScalars();
for (Tensor scalar : scalars) {