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#include "Props.hh"
#include "Compare.hh"
#include "Cleanup.hh"
#include "IndexIterator.hh"
#include "algorithms/collect_factors.hh"
#include "algorithms/collect_terms.hh"
#include "properties/Symbol.hh"
#include "properties/Coordinate.hh"
//#define DEBUG
using namespace cadabra;
collect_factors::collect_factors(const Kernel& k, Ex& e)
: Algorithm(k, e)
{
}
bool collect_factors::can_apply(iterator it)
{
if(*it->name=="\\prod") return true;
return false;
}
// The hash map is such that all objects which are equal have to sit in the same
// bin, but objects in the same bin do not necessarily all have to be equal.
void collect_factors::fill_hash_map(iterator it)
{
factor_hash.clear();
sibling_iterator sib=tr.begin(it);
unsigned int factors=0;
while(sib!=tr.end(it)) { // iterate over all factors in the product
auto chsib=index_iterator::begin(kernel.properties, sib);
auto chend=index_iterator::end(kernel.properties, sib);
bool dontcollect=false;
while(chsib!=chend) { // iterate over all child nodes of a factor
const Symbol *smb=kernel.properties.get<Symbol>(chsib, true);
const Coordinate *coo=kernel.properties.get<Coordinate>(chsib, true);
// std::cerr << chsib << ": " << smb << std::endl;
if((chsib->fl.parent_rel==str_node::p_sub || chsib->fl.parent_rel==str_node::p_super) &&
chsib->is_rational()==false && smb==0 && coo==0) {
dontcollect=true;
break;
}
++chsib;
}
if(!dontcollect) {
if(*sib->name=="\\pow") {
if(tr.begin(sib)->is_rational()==false) // do not collect exponents of numbers
factor_hash.insert(std::pair<hashval_t, sibling_iterator>(tr.calc_hash(tr.begin(sib)), tr.begin(sib)));
}
else
factor_hash.insert(std::pair<hashval_t, sibling_iterator>(tr.calc_hash(sib), sib));
++factors;
}
++sib;
}
}
Algorithm::result_t collect_factors::apply(iterator& st)
{
assert(tr.is_valid(st));
assert(*st->name=="\\prod");
result_t res=result_t::l_no_action;
Ex_comparator comp(kernel.properties);
fill_hash_map(st);
factor_hash_iterator_t ht=factor_hash.begin();
while(ht!=factor_hash.end()) {
hashval_t curr=ht->first; // hash value of the current set of terms
factor_hash_iterator_t thisbin1=ht, thisbin2;
while(thisbin1!=factor_hash.end() && thisbin1->first==curr) {
thisbin2=thisbin1;
++thisbin2;
Ex expsum;
iterator expsumit=expsum.set_head(str_node("\\sum"));
// add the exponent of the first element in this hash bin
if(*(tr.parent((*thisbin1).second)->name)=="\\pow") {
sibling_iterator powch=tr.parent((*thisbin1).second).begin();
++powch;
iterator newch= expsum.append_child(expsumit, iterator(powch));
newch->fl.bracket=str_node::b_round;
}
else {
expsum.append_child(expsumit, str_node("1", str_node::b_round));
}
// FIXME: If the multiplier of this factor is non-zero, we
// have (pure number)**(exp). We need to catch this
// separately. std::cerr << (*thisbin1).second << std::endl;
// For now, we have disabled collecting such factors; sympy
// can do it anyway.
assert(*((*thisbin1).second->multiplier)==1);
// find the other, identical factors
while(thisbin2!=factor_hash.end() && thisbin2->first==curr) {
if(subtree_exact_equal(&kernel.properties, (*thisbin1).second, (*thisbin2).second)) {
// only do something if this factor can be moved to the other one
iterator objnode1=(*thisbin1).second;
iterator objnode2=(*thisbin2).second;
if(*tr.parent(objnode1)->name=="\\pow") objnode1=tr.parent(objnode1);
if(*tr.parent(objnode2)->name=="\\pow") objnode2=tr.parent(objnode2);
if(comp.can_move_adjacent(st, objnode1, objnode2)) {
// all clear
assert(*((*thisbin2).second->multiplier)==1);
res=result_t::l_applied;
if(*(tr.parent((*thisbin2).second)->name)=="\\pow") {
sibling_iterator powch=tr.parent((*thisbin2).second).begin();
++powch;
iterator newch=expsum.append_child(expsumit, iterator(powch));
newch->fl.bracket=str_node::b_round;
}
else {
expsum.append_child(expsumit, str_node("1", str_node::b_round));
}
factor_hash_iterator_t tmp=thisbin2;
++tmp;
if(*(tr.parent((*thisbin2).second)->name)=="\\pow")
tr.erase(tr.parent((*thisbin2).second));
else
tr.erase((*thisbin2).second);
factor_hash.erase(thisbin2);
thisbin2=tmp;
res=result_t::l_applied;
}
else ++thisbin2;
}
else ++thisbin2;
}
// make the modification to the tree
if(expsum.number_of_children(expsum.begin())>1) {
iterator top=expsum.begin();
cleanup_dispatch(kernel,expsum, top);
// cleanup_nests_below(expsum, expsum.begin());
if(! (expsum.begin()->is_identity()) ) {
collect_terms ct(kernel, expsum);
iterator tp=expsum.begin();
ct.apply(tp);
iterator inserthere=thisbin1->second;
if(*(tr.parent(inserthere)->name)=="\\pow")
inserthere=tr.parent(inserthere);
if(expsum.begin()->is_rational() && (expsum.begin()->is_identity() ||
expsum.begin()->is_zero() ) ) {
if(*(inserthere->name)=="\\pow") {
tr.flatten(inserthere);
inserthere=tr.erase(inserthere);
sibling_iterator nxt=inserthere;
++nxt;
tr.erase(nxt);
}
if(expsum.begin()->is_zero()) {
rset_t::iterator rem=inserthere->multiplier;
node_one(inserthere);
inserthere->multiplier=rem;
}
}
else {
Ex repl;
repl.set_head(str_node("\\pow"));
repl.append_child(repl.begin(), iterator((*thisbin1).second));
repl.append_child(repl.begin(), expsum.begin());
if(*(inserthere->name)!="\\pow") {
inserthere=(*thisbin1).second;
}
tr.insert_subtree(inserthere, repl.begin());
tr.erase(inserthere);
}
}
}
// else txtout << "only one left" << std::endl;
++thisbin1;
}
ht=thisbin1;
}
cleanup_dispatch(kernel, tr, st);
return res;
}
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