static RCP<const Basic> diff(const UnivariatePolynomial &self,
const RCP<const Symbol> &x) {
if (self.get_var()->__eq__(*x)) {
map_uint_mpz d;
for (const auto &p : self.get_dict()) {
d[p.first - 1] = p.second * p.first;
}
return make_rcp<const UnivariatePolynomial>(self.get_var(),
(--(d.end()))->first, std::move(d));
} else {
return zero;
}
}
RCP<const UnivariatePolynomial> neg_uni_poly(const UnivariatePolynomial &a)
{
map_int_Expr dict;
for (const auto &it : a.get_dict())
dict[it.first] = -1 * it.second;
return univariate_polynomial(a.get_var(), std::move(dict));
}
RCP<const UnivariatePolynomial> sub_uni_poly(const UnivariatePolynomial &a,
const UnivariatePolynomial &b)
{
map_int_Expr dict;
RCP<const Symbol> var = symbol("");
if (a.get_var()->get_name() == "") {
var = b.get_var();
} else if (b.get_var()->get_name() == "") {
var = a.get_var();
} else if (!(a.get_var()->__eq__(*b.get_var()))) {
throw std::runtime_error("Error: variables must agree.");
} else {
var = a.get_var();
}
for (const auto &it : a.get_dict())
dict[it.first] = it.second;
for (const auto &it : b.get_dict())
dict[it.first] -= it.second;
return univariate_polynomial(var, std::move(dict));
}
// UnivariatePolynomial printing, tests taken from SymPy and printing ensures
// that there is compatibility
void StrPrinter::bvisit(const UnivariatePolynomial &x)
{
std::ostringstream s;
// bool variable needed to take care of cases like -5, -x, -3*x etc.
bool first = true;
// we iterate over the map in reverse order so that highest degree gets
// printed first
for (auto it = x.get_dict().rbegin(); it != x.get_dict().rend(); ++it) {
std::string t;
// if exponent is 0, then print only coefficient
if (it->first == 0) {
if (first) {
s << it->second;
} else {
t = parenthesizeLT(it->second.get_basic(), PrecedenceEnum::Mul);
if (t[0] == '-') {
s << " - " << t.substr(1);
} else {
s << " + " << t;
}
}
first = false;
continue;
}
// if the coefficient of a term is +1 or -1
if (it->second == 1 or it->second == -1) {
// in cases of -x, print -x
// in cases of x**2 - x, print - x
if (first) {
if (it->second == -1)
s << "-";
} else {
s << " " << _print_sign(static_cast<const Integer &>(
*it->second.get_basic())
.as_mpz())
<< " ";
}
}
// same logic is followed as above
else {
// in cases of -2*x, print -2*x
// in cases of x**2 - 2*x, print - 2*x
if (first) {
s << parenthesizeLT(it->second.get_basic(), PrecedenceEnum::Mul)
<< "*";
} else {
t = parenthesizeLT(it->second.get_basic(), PrecedenceEnum::Mul);
if (t[0] == '-') {
s << " - " << t.substr(1);
} else {
s << " + " << t;
}
s << "*";
}
}
s << x.get_var()->get_name();
// if exponent is not 1, print the exponent;
if (it->first > 1) {
s << "**" << it->first;
} else if (it->first < 0) {
s << "**(" << it->first << ")";
}
// corner cases of only first term handled successfully, switch the bool
first = false;
}
if (x.get_dict().size() == 0)
s << "0";
str_ = s.str();
}