int factorial(const MultipleDeriv& ms)
{
Sundance::Map<Deriv, int> counts;
for (MultipleDeriv::const_iterator i=ms.begin(); i!=ms.end(); i++)
{
if (counts.containsKey(*i)) counts[*i]++;
else counts.put(*i, 1);
}
int rtn = 1;
for (Sundance::Map<Deriv, int>::const_iterator
i=counts.begin(); i!=counts.end(); i++)
{
int f = 1;
for (int j=1; j<=i->second; j++) f *= j;
rtn *= f;
}
return rtn;
}
bool ReorderSum::doTransform(const RCP<ScalarExpr>& left,
const RCP<ScalarExpr>& right,
int sign, RCP<ScalarExpr>& rtn) const
{
TimeMonitor timer(reorderSumTimer());
/* first we check to see whether the terms are already in order.
* The left and right trees are already ordered, so that if the
* first term on the right is after the last term on the left, the
* combination of both is already ordered. In that case, nothing more needs
* to be done.
*/
Expr L = Expr::handle(left);
Expr R = Expr::handle(right);
Sundance::Map<Expr, int> tree = L.getSumTree();
Sundance::Map<Expr, int>::const_reverse_iterator iL = tree.rbegin();
Expr endOfLeft = iL->first;
Sundance::Map<Expr, int> rightTree = R.getSumTree();
Sundance::Map<Expr, int>::const_iterator iR = rightTree.begin();
Expr startOfRight = iR->first;
if (endOfLeft.lessThan(startOfRight))
{
Tabs tab1;
SUNDANCE_VERB_MEDIUM(tab1 << "Terms are already ordered, doing nothing");
return false;
}
else
{
Tabs tab1;
for (Map<Expr, int>::const_iterator i=rightTree.begin(); i!=rightTree.end(); i++)
{
int leftCount = 0;
if (tree.containsKey(i->first))
{
leftCount = tree[i->first];
}
int count = leftCount + sign * i->second;
tree.put(i->first, count);
}
SUNDANCE_VERB_MEDIUM(tab1 << "Ordered terms are: " << tree);
Expr sum = new ZeroExpr();
/* add up all terms. If no terms are left after cancellations, the result will
* be zero. */
for (Map<Expr, int>::const_iterator i=tree.begin(); i!=tree.end(); i++)
{
const Expr& term = i->first;
int count = i->second;
if (count==0) continue;
if (count==1) sum = sum + term;
else if (count==-1) sum = sum - term;
else sum = sum + count*term;
}
rtn = getScalar(sum);
return true;
}
}