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Keep track of precision requested in gmp_float.

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Fixes: https://github.com/boostorg/multiprecision/issues/164.
This commit is contained in:
jzmaddock
2019-11-08 14:00:35 +00:00
parent 8597a212e0
commit 2f504dd60e
1 changed files with 57 additions and 24 deletions
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81
include/boost/multiprecision/gmp.hpp
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@@ -515,45 +515,59 @@ struct gmp_float : public detail::gmp_float_imp<digits10>
template <>
struct gmp_float<0> : public detail::gmp_float_imp<0>
{
gmp_float()
//
// We have a problem with mpf_t in that the precision we request isn't what we get.
// As a result the front end can end up chasing it's tail trying to create a variable
// with the the correct precision to hold the result of an expression.
// See: https://github.com/boostorg/multiprecision/issues/164
// The problem is made worse by the fact that our conversions from base10 to 2 and
// vice-versa do not exactly round trip (and probably never will).
// The workaround is to keep track of the precision requested, and always return
// that as the current actual precision.
//
private:
unsigned requested_precision;
public:
gmp_float() : requested_precision(get_default_precision())
{
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(get_default_precision()));
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
}
gmp_float(const mpf_t val)
gmp_float(const mpf_t val) : requested_precision(get_default_precision())
{
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(get_default_precision()));
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
mpf_set(this->m_data, val);
}
gmp_float(const mpz_t val)
gmp_float(const mpz_t val) : requested_precision(get_default_precision())
{
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(get_default_precision()));
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
mpf_set_z(this->m_data, val);
}
gmp_float(const mpq_t val)
gmp_float(const mpq_t val) : requested_precision(get_default_precision())
{
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(get_default_precision()));
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
mpf_set_q(this->m_data, val);
}
gmp_float(const gmp_float& o) : detail::gmp_float_imp<0>(o) {}
gmp_float(const gmp_float& o) : detail::gmp_float_imp<0>(o), requested_precision(o.requested_precision) {}
template <unsigned D>
gmp_float(const gmp_float<D>& o)
{
mpf_init2(this->m_data, mpf_get_prec(o.data()));
mpf_set(this->m_data, o.data());
requested_precision = multiprecision::detail::digits2_2_10(static_cast<unsigned long>(mpf_get_prec(this->m_data)));
}
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
gmp_float(gmp_float&& o) BOOST_NOEXCEPT : detail::gmp_float_imp<0>(static_cast<detail::gmp_float_imp<0>&&>(o))
gmp_float(gmp_float&& o) BOOST_NOEXCEPT : detail::gmp_float_imp<0>(static_cast<detail::gmp_float_imp<0>&&>(o)), requested_precision(o.requested_precision)
{}
#endif
gmp_float(const gmp_int& o);
gmp_float(const gmp_rational& o);
gmp_float(const gmp_float& o, unsigned digits10)
gmp_float(const gmp_float& o, unsigned digits10) : requested_precision(digits10)
{
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(digits10));
mpf_set(this->m_data, o.data());
}
template <class V>
gmp_float(const V& o, unsigned digits10)
gmp_float(const V& o, unsigned digits10) : requested_precision(digits10)
{
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(digits10));
*this = o;
@@ -564,7 +578,7 @@ struct gmp_float<0> : public detail::gmp_float_imp<0>
// Support for new types in C++17
//
template <class Traits>
gmp_float(const std::basic_string_view<char, Traits>& o, unsigned digits10)
gmp_float(const std::basic_string_view<char, Traits>& o, unsigned digits10) : requested_precision(digits10)
{
using default_ops::assign_from_string_view;
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(digits10));
@@ -574,12 +588,14 @@ struct gmp_float<0> : public detail::gmp_float_imp<0>
gmp_float& operator=(const gmp_float& o)
{
*static_cast<detail::gmp_float_imp<0>*>(this) = static_cast<detail::gmp_float_imp<0> const&>(o);
requested_precision = o.requested_precision;
return *this;
}
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
gmp_float& operator=(gmp_float&& o) BOOST_NOEXCEPT
{
*static_cast<detail::gmp_float_imp<0>*>(this) = static_cast<detail::gmp_float_imp<0>&&>(o);
requested_precision = o.requested_precision;
return *this;
}
#endif
@@ -595,6 +611,7 @@ struct gmp_float<0> : public detail::gmp_float_imp<0>
mpf_set_prec(this->m_data, mpf_get_prec(o.data()));
}
mpf_set(this->m_data, o.data());
requested_precision = o.requested_precision;
return *this;
}
gmp_float& operator=(const gmp_int& o);
@@ -602,21 +619,30 @@ struct gmp_float<0> : public detail::gmp_float_imp<0>
gmp_float& operator=(const mpf_t val)
{
if (this->m_data[0]._mp_d == 0)
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(get_default_precision()));
{
requested_precision = get_default_precision();
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
}
mpf_set(this->m_data, val);
return *this;
}
gmp_float& operator=(const mpz_t val)
{
if (this->m_data[0]._mp_d == 0)
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(get_default_precision()));
{
requested_precision = get_default_precision();
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
}
mpf_set_z(this->m_data, val);
return *this;
}
gmp_float& operator=(const mpq_t val)
{
if (this->m_data[0]._mp_d == 0)
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(get_default_precision()));
{
requested_precision = get_default_precision();
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
}
mpf_set_q(this->m_data, val);
return *this;
}
@@ -636,11 +662,12 @@ struct gmp_float<0> : public detail::gmp_float_imp<0>
}
unsigned precision() const BOOST_NOEXCEPT
{
return static_cast<unsigned>(multiprecision::detail::digits2_2_10(static_cast<unsigned long>(mpf_get_prec(this->m_data))));
return requested_precision;
}
void precision(unsigned digits10) BOOST_NOEXCEPT
{
mpf_set_prec(this->m_data, multiprecision::detail::digits10_2_2(digits10));
requested_precision = digits10;
mpf_set_prec(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
}
};
@@ -2273,27 +2300,33 @@ inline gmp_float<Digits10>& gmp_float<Digits10>::operator=(const gmp_rational& o
mpf_set_q(this->data(), o.data());
return *this;
}
inline gmp_float<0>::gmp_float(const gmp_int& o)
inline gmp_float<0>::gmp_float(const gmp_int& o) : requested_precision(get_default_precision())
{
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(get_default_precision()));
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
mpf_set_z(this->data(), o.data());
}
inline gmp_float<0>::gmp_float(const gmp_rational& o)
inline gmp_float<0>::gmp_float(const gmp_rational& o) : requested_precision(get_default_precision())
{
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(get_default_precision()));
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
mpf_set_q(this->data(), o.data());
}
inline gmp_float<0>& gmp_float<0>::operator=(const gmp_int& o)
{
if (this->m_data[0]._mp_d == 0)
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(this->get_default_precision()));
{
requested_precision = this->get_default_precision();
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
}
mpf_set_z(this->data(), o.data());
return *this;
}
inline gmp_float<0>& gmp_float<0>::operator=(const gmp_rational& o)
{
if (this->m_data[0]._mp_d == 0)
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(this->get_default_precision()));
{
requested_precision = this->get_default_precision();
mpf_init2(this->m_data, multiprecision::detail::digits10_2_2(requested_precision));
}
mpf_set_q(this->data(), o.data());
return *this;
}