RCP<Basic> pow_expand(const RCP<Pow> &self)
{
if (is_a<Integer>(*self->exp_)) {
if (is_a<Add>(*self->base_)) {
map_vec_mpz r;
int n = rcp_dynamic_cast<Integer>(self->exp_)->as_int();
RCP<Add> base = rcp_dynamic_cast<Add>(self->base_);
int m = base->dict_.size();
multinomial_coefficients_mpz(m, n, r);
Dict_int rd;
for (auto &p: r) {
auto power = p.first.begin();
auto i2 = base->dict_.begin();
Dict_int d;
for (; power != p.first.end(); ++power, ++i2) {
if (*power > 0) {
RCP<Integer> exp = rcp(new Integer(*power));
RCP<Basic> base = i2->first;
d[base] = exp;
}
}
RCP<Basic> term = Mul::from_dict(one, d);
rd[term] = rcp(new Integer(p.second));
}
RCP<Basic> result = Add::from_dict(rd);
return result;
}
}
return self;
}
RCP<const Basic> pow_expand(const RCP<const Pow> &self)
{
RCP<const Basic> _base = expand(self->base_);
bool negative_pow = false;
if (! is_a<Integer>(*self->exp_) || ! is_a<Add>(*_base)) {
if (neq(_base, self->base_)) {
return pow(_base, self->exp_);
} else {
return self;
}
}
map_vec_mpz r;
int n = rcp_static_cast<const Integer>(self->exp_)->as_int();
if (n < 0) {
n = -n;
negative_pow = true;
}
RCP<const Add> base = rcp_static_cast<const Add>(_base);
umap_basic_num base_dict = base->dict_;
if (! (base->coef_->is_zero())) {
// Add the numerical coefficient into the dictionary. This
// allows a little bit easier treatment below.
insert(base_dict, base->coef_, one);
}
int m = base_dict.size();
multinomial_coefficients_mpz(m, n, r);
umap_basic_num rd;
// This speeds up overall expansion. For example for the benchmark
// (y + x + z + w)^60 it improves the timing from 135ms to 124ms.
rd.reserve(2*r.size());
RCP<const Number> add_overall_coeff=zero;
for (auto &p: r) {
auto power = p.first.begin();
auto i2 = base_dict.begin();
map_basic_basic d;
RCP<const Number> overall_coeff=one;
for (; power != p.first.end(); ++power, ++i2) {
if (*power > 0) {
RCP<const Integer> exp = rcp(new Integer(*power));
RCP<const Basic> base = i2->first;
if (is_a<Integer>(*base)) {
imulnum(outArg(overall_coeff),
rcp_static_cast<const Number>(
rcp_static_cast<const Integer>(base)->powint(*exp)));
} else if (is_a<Symbol>(*base)) {
Mul::dict_add_term(d, exp, base);
} else {
RCP<const Basic> exp2, t, tmp;
tmp = pow(base, exp);
if (is_a<Mul>(*tmp)) {
for (auto &p: (rcp_static_cast<const Mul>(tmp))->dict_) {
Mul::dict_add_term_new(outArg(overall_coeff), d,
p.second, p.first);
}
imulnum(outArg(overall_coeff), (rcp_static_cast<const Mul>(tmp))->coef_);
} else {
Mul::as_base_exp(tmp, outArg(exp2), outArg(t));
Mul::dict_add_term_new(outArg(overall_coeff), d, exp2, t);
}
}
if (!(i2->second->is_one())) {
if (is_a<Integer>(*(i2->second)) || is_a<Rational>(*(i2->second))) {
imulnum(outArg(overall_coeff),
pownum(i2->second,
rcp_static_cast<const Number>(exp)));
} else if (is_a<Complex>(*(i2->second))) {
RCP<const Number> tmp = rcp_static_cast<const Complex>(i2->second)->pow(*exp);
imulnum(outArg(overall_coeff), tmp);
}
}
}
}
RCP<const Basic> term = Mul::from_dict(overall_coeff, std::move(d));
RCP<const Number> coef2 = rcp(new Integer(p.second));
if (is_a_Number(*term)) {
iaddnum(outArg(add_overall_coeff),
mulnum(rcp_static_cast<const Number>(term), coef2));
} else {
if (is_a<Mul>(*term) &&
!(rcp_static_cast<const Mul>(term)->coef_->is_one())) {
// Tidy up things like {2x: 3} -> {x: 6}
imulnum(outArg(coef2),
rcp_static_cast<const Mul>(term)->coef_);
// We make a copy of the dict_:
map_basic_basic d2 = rcp_static_cast<const Mul>(term)->dict_;
term = Mul::from_dict(one, std::move(d2));
}
Add::dict_add_term(rd, coef2, term);
}
}
RCP<const Basic> result = Add::from_dict(add_overall_coeff, std::move(rd));
if (negative_pow) result = pow(result, minus_one);
return result;
}
