/**
* @param[in] args reference set of piranha::symbol.
*
* @return degree of the monomial.
*
* @throws std::invalid_argument if the size of \p args is greater than one or
* if the size is zero and the exponent is not zero.
* @throws unspecified any exception thrown by piranha::math::is_zero().
*/
T degree(const symbol_set &args) const
{
if (unlikely(args.size() > 1u || (!args.size() && !math::is_zero(m_value)))) {
piranha_throw(std::invalid_argument,"invalid symbol set");
}
return m_value;
}
void multiply(univariate_monomial &retval, const univariate_monomial<U> &other, const symbol_set &args) const
{
if (unlikely(args.size() > 1u || (!args.size() && (!math::is_zero(m_value) || !math::is_zero(other.m_value))))) {
piranha_throw(std::invalid_argument,"invalid symbol set");
}
retval.m_value = m_value;
retval.m_value += other.m_value;
}
/**
* A monomial is unitary if piranha::math::is_zero() on its exponent returns \p true.
*
* @param[in] args reference set of piranha::symbol.
*
* @return \p true if the monomial is unitary, \p false otherwise.
*
* @throws std::invalid_argument if the size of \p args is greater than one or
* if the size is zero and the exponent is not zero.
* @throws unspecified any exception thrown by piranha::math::is_zero().
*/
bool is_unitary(const symbol_set &args) const
{
const bool is_zero = math::is_zero(m_value);
if (unlikely(args.size() > 1u || (!args.size() && !is_zero))) {
piranha_throw(std::invalid_argument,"invalid symbol set");
}
return is_zero;
}
/**
* Arguments merging in case of univariate monomial is meaningful only when extending a zero-arguments
* monomial to one argument. Therefore, this method will either throw or return a default-constructed monomial.
*
* @param[in] orig_args original arguments.
* @param[in] new_args new arguments.
*
* @return a default-constructed instance of piranha::univariate_monomial.
*
* @throws std::invalid_argument if the size of \p new_args is different from 1 or the size of \p orig_args is not zero.
* @throws unspecified any exception thrown by the default constructor of piranha::univariate_monomial.
*/
univariate_monomial merge_args(const symbol_set &orig_args, const symbol_set &new_args) const
{
piranha_assert(std::is_sorted(orig_args.begin(),orig_args.end()));
piranha_assert(std::is_sorted(new_args.begin(),new_args.end()));
if (unlikely(new_args.size() != 1u || orig_args.size())) {
piranha_throw(std::invalid_argument,"invalid symbol set");
}
piranha_assert(math::is_zero(m_value));
// The only valid possibility here is that a monomial with zero args is extended
// to one arg. Default construction is ok.
return univariate_monomial();
}
/**
* Will print to stream a human-readable representation of the monomial.
*
* @param[in] os target stream.
* @param[in] args reference set of piranha::symbol.
*
* @throws std::invalid_argument if the size of \p args is greater than one or
* if the size is zero and the exponent is not zero.
* @throws unspecified any exception thrown by:
* - piranha::math::is_zero(),
* - construction of the exponent type from \p int,
* - comparison of exponents,
* - printing exponents to stream.
*/
void print(std::ostream &os, const symbol_set &args) const
{
if (unlikely(args.size() > 1u || (!args.size() && !math::is_zero(m_value)))) {
piranha_throw(std::invalid_argument,"invalid symbol set");
}
const value_type zero(0), one(1);
if (args.size() && m_value != zero) {
os << args[0u].get_name();
if (m_value != one) {
os << "**" << m_value;
}
}
}
/**
* Partial degree of the monomial: only the symbols with names in \p active_args are considered during the computation
* of the degree. Symbols in \p active_args not appearing in \p args are not considered.
*
* @param[in] active_args names of the symbols that will be considered in the computation of the partial degree of the monomial.
* @param[in] args reference set of piranha::symbol.
*
* @return the summation of all the exponents of the monomial corresponding to the symbols in
* \p active_args, or <tt>value_type(0)</tt> if no symbols in \p active_args appear in \p args.
*
* @throws std::invalid_argument if the size of \p args is greater than one or
* if the size is zero and the exponent is not zero.
* @throws unspecified any exception thrown by piranha::math::is_zero() or by constructing an instance of \p T from zero.
*/
T degree(const std::set<std::string> &active_args, const symbol_set &args) const
{
if (unlikely(args.size() > 1u || (!args.size() && !math::is_zero(m_value)))) {
piranha_throw(std::invalid_argument,"invalid symbol set");
}
if (!args.size()) {
return T(0);
}
piranha_assert(args.size() == 1u);
// Look for the only symbol in active args, if we find it return its exponent.
const bool is_present = std::binary_search(active_args.begin(),active_args.end(),args[0].get_name());
if (is_present) {
return m_value;
} else {
return T(0);
}
}
/**
* Will print to stream a TeX representation of the monomial.
*
* @param[in] os target stream.
* @param[in] args reference set of piranha::symbol.
*
* @throws std::invalid_argument if the size of \p args is greater than one or
* if the size is zero and the exponent is not zero.
* @throws unspecified any exception thrown by:
* - piranha::math::is_zero() and piranha::math::negate(),
* - construction of the exponent type,
* - comparison of exponents,
* - printing exponents to stream.
*/
void print_tex(std::ostream &os, const symbol_set &args) const
{
if (unlikely(args.size() > 1u || (!args.size() && !math::is_zero(m_value)))) {
piranha_throw(std::invalid_argument,"invalid symbol set");
}
const value_type zero(0), one(1);
value_type copy(m_value);
bool sign_change = false;
if (args.size() && copy != zero) {
if (copy < zero) {
math::negate(copy);
os << "\\frac{1}{";
sign_change = true;
}
os << "{" << args[0u].get_name() << "}";
if (copy != one) {
os << "^{" << copy << "}";
}
if (sign_change) {
os << "}";
}
}
}
/**
* @param[in] args reference arguments set.
*
* @return \p true if the size of \p args is 1 or if the size of \p args is 0 and piranha::math::is_zero()
* on the exponent returns \p true.
*/
bool is_compatible(const symbol_set &args) const noexcept(true)
{
const auto size = args.size();
return (size == 1u || (!size && math::is_zero(m_value)));
}
/**
* This constructor will initialise the value of the exponent to 0.
*
* @param[in] args set of symbols used for construction.
*
* @throws std::invalid_argument if the size of \p args is greater than 1.
* @throws unspecified any exception thrown by the construction of an instance of \p T from 0.
*/
explicit univariate_monomial(const symbol_set &args):m_value(0)
{
if (unlikely(args.size() > 1u)) {
piranha_throw(std::invalid_argument,"excessive number of symbols for univariate monomial");
}
}