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Merge pull request #1298 from andrjohns/log-pi-constant

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Add new constant `log_pi`
This commit is contained in:
Matt Borland
2025-08-14 11:15:40 +02:00
committed by GitHub
parent 4d7d6e1982 0353afe0d7
commit 2519259c91
5 changed files with 25 additions and 3 deletions
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1
doc/constants/constants.qbk
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@@ -340,6 +340,7 @@ This section lists the mathematical constants, their use(s) (and sometimes ratio
[[pi_minus_three] [[pi]-3] [0.141593] [] ]
[[four_minus_pi] [4 -[pi]] [0.858407] [] ]
[[pi_pow_e] [[pi][super e]] [22.4591] [] ]
[[log_pi] [ln([pi])] [1.14473] [] ]
[[pi_sqr] [[pi][super 2]] [9.86960] [] ]
[[pi_sqr_div_six] [[pi][super 2]/6] [1.64493] [] ]

8
include/boost/math/constants/calculate_constants.hpp
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@@ -95,6 +95,14 @@ inline T constant_one_div_two_pi<T>::compute(BOOST_MATH_EXPLICIT_TEMPLATE_TYPE_S
return 1 / two_pi<T, policies::policy<policies::digits2<N> > >();
}
template <class T>
template<int N>
inline T constant_log_pi<T>::compute(BOOST_MATH_EXPLICIT_TEMPLATE_TYPE_SPEC((std::integral_constant<int, N>)))
{
BOOST_MATH_STD_USING
return log(pi<T, policies::policy<policies::digits2<N> > >());
}
template <class T>
template<int N>
inline T constant_root_pi<T>::compute(BOOST_MATH_EXPLICIT_TEMPLATE_TYPE_SPEC((std::integral_constant<int, N>)))

3
include/boost/math/constants/constants.hpp
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@@ -280,6 +280,7 @@ namespace constants {
BOOST_DEFINE_MATH_CONSTANT(four_thirds_pi, 4.188790204786390984616857844372670512e+00, "4.18879020478639098461685784437267051226289253250014109463325945641042187504827866483737976712282275730953078202e+00")
BOOST_DEFINE_MATH_CONSTANT(one_div_two_pi, 1.591549430918953357688837633725143620e-01, "1.59154943091895335768883763372514362034459645740456448747667344058896797634226535090113802766253085956072842727e-01")
BOOST_DEFINE_MATH_CONSTANT(one_div_root_two_pi, 3.989422804014326779399460599343818684e-01, "3.98942280401432677939946059934381868475858631164934657665925829670657925899301838501252333907306936430302558863e-01")
BOOST_DEFINE_MATH_CONSTANT(log_pi, 1.144729885849400174143427351353058711e+00, "1.14472988584940017414342735135305871164729481291531157151362307147213776988482607978362327027548970770200981223e+00")
BOOST_DEFINE_MATH_CONSTANT(root_pi, 1.772453850905516027298167483341145182e+00, "1.77245385090551602729816748334114518279754945612238712821380778985291128459103218137495065673854466541622682362e+00")
BOOST_DEFINE_MATH_CONSTANT(root_half_pi, 1.253314137315500251207882642405522626e+00, "1.25331413731550025120788264240552262650349337030496915831496178817114682730392098747329791918902863305800498633e+00")
BOOST_DEFINE_MATH_CONSTANT(root_two_pi, 2.506628274631000502415765284811045253e+00, "2.50662827463100050241576528481104525300698674060993831662992357634229365460784197494659583837805726611600997267e+00")
@@ -357,5 +358,3 @@ BOOST_MATH_GPU_ENABLED inline constexpr T tau() { return two_pi<T>(); }
#endif
#endif // BOOST_MATH_CONSTANTS_CONSTANTS_INCLUDED

2
test/test_constant_generate.cpp
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@@ -48,6 +48,7 @@ int main()
BOOST_CONSTANTS_GENERATE(four_thirds_pi);
BOOST_CONSTANTS_GENERATE(one_div_two_pi);
BOOST_CONSTANTS_GENERATE(one_div_root_two_pi);
BOOST_CONSTANTS_GENERATE(log_pi);
BOOST_CONSTANTS_GENERATE(root_pi);
BOOST_CONSTANTS_GENERATE(root_half_pi);
BOOST_CONSTANTS_GENERATE(root_two_pi);
@@ -189,4 +190,3 @@ Output
*/

14
test/test_constants.cpp
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@@ -103,6 +103,7 @@ void test_spots(RealType)
BOOST_MATH_STD_USING
CHECK_ULP_CLOSE(3.14159265358979323846264338327950288419716939937510L, pi<RealType>(), 2);
CHECK_ULP_CLOSE(log(3.14159265358979323846264338327950288419716939937510L), log_pi<RealType>(), 2);
CHECK_ULP_CLOSE(sqrt(3.14159265358979323846264338327950288419716939937510L), root_pi<RealType>(), 2);
CHECK_ULP_CLOSE(sqrt(3.14159265358979323846264338327950288419716939937510L/2), root_half_pi<RealType>(), 2);
CHECK_ULP_CLOSE(sqrt(3.14159265358979323846264338327950288419716939937510L * 2), root_two_pi<RealType>(), 2);
@@ -160,6 +161,7 @@ void test_spots(RealType)
CHECK_ULP_CLOSE(1 / (3.14159265358979323846264338327950288419716939937510L), one_div_pi<RealType>(), 2);
CHECK_ULP_CLOSE(2 / (3.14159265358979323846264338327950288419716939937510L), two_div_pi<RealType>(), 2);
CHECK_ULP_CLOSE(1 / (2 * 3.14159265358979323846264338327950288419716939937510L), one_div_two_pi<RealType>(), 2);
CHECK_ULP_CLOSE(log(3.14159265358979323846264338327950288419716939937510L), log_pi<RealType>(), 2);
CHECK_ULP_CLOSE(sqrt(3.14159265358979323846264338327950288419716939937510L), root_pi<RealType>(), 2);
CHECK_ULP_CLOSE(sqrt(3.14159265358979323846264338327950288419716939937510L / 2), root_half_pi<RealType>(), 2);
CHECK_ULP_CLOSE(sqrt(2 * 3.14159265358979323846264338327950288419716939937510L), root_two_pi<RealType>(), 2);
@@ -242,6 +244,7 @@ void test_float_spots()
BOOST_MATH_STD_USING
CHECK_ULP_CLOSE(static_cast<float>(3.14159265358979323846264338327950288419716939937510F), pi, 2);
CHECK_ULP_CLOSE(static_cast<float>(log(3.14159265358979323846264338327950288419716939937510F)), log_pi, 2);
CHECK_ULP_CLOSE(static_cast<float>(sqrt(3.14159265358979323846264338327950288419716939937510F)), root_pi, 2);
CHECK_ULP_CLOSE(static_cast<float>(sqrt(3.14159265358979323846264338327950288419716939937510F/2)), root_half_pi, 2);
CHECK_ULP_CLOSE(static_cast<float>(sqrt(3.14159265358979323846264338327950288419716939937510F * 2)), root_two_pi, 2);
@@ -293,6 +296,7 @@ void test_float_spots()
CHECK_ULP_CLOSE(static_cast<float>(1 / (3.14159265358979323846264338327950288419716939937510F)), one_div_pi, 2);
CHECK_ULP_CLOSE(static_cast<float>(2 / (3.14159265358979323846264338327950288419716939937510F)), two_div_pi, 2);
CHECK_ULP_CLOSE(static_cast<float>(1 / (2 * 3.14159265358979323846264338327950288419716939937510F)), one_div_two_pi, 2);
CHECK_ULP_CLOSE(static_cast<float>(log(3.14159265358979323846264338327950288419716939937510F)), log_pi, 2);
CHECK_ULP_CLOSE(static_cast<float>(sqrt(3.14159265358979323846264338327950288419716939937510F)), root_pi, 2);
CHECK_ULP_CLOSE(static_cast<float>(sqrt(3.14159265358979323846264338327950288419716939937510F / 2)), root_half_pi, 2);
CHECK_ULP_CLOSE(static_cast<float>(sqrt(2 * 3.14159265358979323846264338327950288419716939937510F)), root_two_pi, 2);
@@ -362,6 +366,7 @@ void test_f32_spots()
BOOST_MATH_STD_USING
CHECK_ULP_CLOSE(static_cast<std::float32_t>(3.14159265358979323846264338327950288419716939937510F32), pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float32_t>(log(3.14159265358979323846264338327950288419716939937510F32)), log_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float32_t>(sqrt(3.14159265358979323846264338327950288419716939937510F32)), root_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float32_t>(sqrt(3.14159265358979323846264338327950288419716939937510F32/2)), root_half_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float32_t>(sqrt(3.14159265358979323846264338327950288419716939937510F32 * 2)), root_two_pi, 2);
@@ -413,6 +418,7 @@ void test_f32_spots()
CHECK_ULP_CLOSE(static_cast<std::float32_t>(1 / (3.14159265358979323846264338327950288419716939937510F32)), one_div_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float32_t>(2 / (3.14159265358979323846264338327950288419716939937510F32)), two_div_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float32_t>(1 / (2 * 3.14159265358979323846264338327950288419716939937510F32)), one_div_two_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float32_t>(log(3.14159265358979323846264338327950288419716939937510F32)), log_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float32_t>(sqrt(3.14159265358979323846264338327950288419716939937510F32)), root_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float32_t>(sqrt(3.14159265358979323846264338327950288419716939937510F32 / 2)), root_half_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float32_t>(sqrt(2 * 3.14159265358979323846264338327950288419716939937510F32)), root_two_pi, 2);
@@ -482,6 +488,7 @@ void test_double_spots()
BOOST_MATH_STD_USING
CHECK_ULP_CLOSE(static_cast<double>(3.14159265358979323846264338327950288419716939937510), pi, 2);
CHECK_ULP_CLOSE(static_cast<double>(log(3.14159265358979323846264338327950288419716939937510)), log_pi, 2);
CHECK_ULP_CLOSE(static_cast<double>(sqrt(3.14159265358979323846264338327950288419716939937510)), root_pi, 2);
CHECK_ULP_CLOSE(static_cast<double>(sqrt(3.14159265358979323846264338327950288419716939937510/2)), root_half_pi, 2);
CHECK_ULP_CLOSE(static_cast<double>(sqrt(3.14159265358979323846264338327950288419716939937510 * 2)), root_two_pi, 2);
@@ -533,6 +540,7 @@ void test_double_spots()
CHECK_ULP_CLOSE(static_cast<double>(1 / (3.14159265358979323846264338327950288419716939937510)), one_div_pi, 2);
CHECK_ULP_CLOSE(static_cast<double>(2 / (3.14159265358979323846264338327950288419716939937510)), two_div_pi, 2);
CHECK_ULP_CLOSE(static_cast<double>(1 / (2 * 3.14159265358979323846264338327950288419716939937510)), one_div_two_pi, 2);
CHECK_ULP_CLOSE(static_cast<double>(log(3.14159265358979323846264338327950288419716939937510)), log_pi, 2);
CHECK_ULP_CLOSE(static_cast<double>(sqrt(3.14159265358979323846264338327950288419716939937510)), root_pi, 2);
CHECK_ULP_CLOSE(static_cast<double>(sqrt(3.14159265358979323846264338327950288419716939937510 / 2)), root_half_pi, 2);
CHECK_ULP_CLOSE(static_cast<double>(sqrt(2 * 3.14159265358979323846264338327950288419716939937510)), root_two_pi, 2);
@@ -601,6 +609,7 @@ void test_f64_spots()
BOOST_MATH_STD_USING
CHECK_ULP_CLOSE(static_cast<std::float64_t>(3.14159265358979323846264338327950288419716939937510F64), pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float64_t>(log(3.14159265358979323846264338327950288419716939937510F64)), log_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float64_t>(sqrt(3.14159265358979323846264338327950288419716939937510F64)), root_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float64_t>(sqrt(3.14159265358979323846264338327950288419716939937510F64/2)), root_half_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float64_t>(sqrt(3.14159265358979323846264338327950288419716939937510F64 * 2)), root_two_pi, 2);
@@ -652,6 +661,7 @@ void test_f64_spots()
CHECK_ULP_CLOSE(static_cast<std::float64_t>(1 / (3.14159265358979323846264338327950288419716939937510F64)), one_div_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float64_t>(2 / (3.14159265358979323846264338327950288419716939937510F64)), two_div_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float64_t>(1 / (2 * 3.14159265358979323846264338327950288419716939937510F64)), one_div_two_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float64_t>(log(3.14159265358979323846264338327950288419716939937510F64)), log_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float64_t>(sqrt(3.14159265358979323846264338327950288419716939937510F64)), root_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float64_t>(sqrt(3.14159265358979323846264338327950288419716939937510F64 / 2)), root_half_pi, 2);
CHECK_ULP_CLOSE(static_cast<std::float64_t>(sqrt(2 * 3.14159265358979323846264338327950288419716939937510F64)), root_two_pi, 2);
@@ -724,6 +734,7 @@ void test_long_double_spots()
BOOST_MATH_STD_USING
CHECK_ULP_CLOSE(static_cast<long double>(3.14159265358979323846264338327950288419716939937510L), pi, 2);
CHECK_ULP_CLOSE(static_cast<long double>(log(3.14159265358979323846264338327950288419716939937510L)), log_pi, 2);
CHECK_ULP_CLOSE(static_cast<long double>(sqrt(3.14159265358979323846264338327950288419716939937510L)), root_pi, 2);
CHECK_ULP_CLOSE(static_cast<long double>(sqrt(3.14159265358979323846264338327950288419716939937510L/2)), root_half_pi, 2);
CHECK_ULP_CLOSE(static_cast<long double>(sqrt(3.14159265358979323846264338327950288419716939937510L * 2)), root_two_pi, 2);
@@ -775,6 +786,7 @@ void test_long_double_spots()
CHECK_ULP_CLOSE(static_cast<long double>(1 / (3.14159265358979323846264338327950288419716939937510L)), one_div_pi, 2);
CHECK_ULP_CLOSE(static_cast<long double>(2 / (3.14159265358979323846264338327950288419716939937510L)), two_div_pi, 2);
CHECK_ULP_CLOSE(static_cast<long double>(1 / (2 * 3.14159265358979323846264338327950288419716939937510L)), one_div_two_pi, 2);
CHECK_ULP_CLOSE(static_cast<long double>(log(3.14159265358979323846264338327950288419716939937510L)), log_pi, 2);
CHECK_ULP_CLOSE(static_cast<long double>(sqrt(3.14159265358979323846264338327950288419716939937510L)), root_pi, 2);
CHECK_ULP_CLOSE(static_cast<long double>(sqrt(3.14159265358979323846264338327950288419716939937510L / 2)), root_half_pi, 2);
CHECK_ULP_CLOSE(static_cast<long double>(sqrt(2 * 3.14159265358979323846264338327950288419716939937510L)), root_two_pi, 2);
@@ -851,6 +863,7 @@ void test_real_concept_policy(const Policy&)
BOOST_MATH_STD_USING
CHECK_ULP_CLOSE(3.14159265358979323846264338327950288419716939937510L, (pi<real_concept, Policy>)(), 2);
CHECK_ULP_CLOSE(log(3.14159265358979323846264338327950288419716939937510L), (log_pi<real_concept, Policy>)(), 2);
CHECK_ULP_CLOSE(sqrt(3.14159265358979323846264338327950288419716939937510L), (root_pi<real_concept, Policy>)(), 2);
CHECK_ULP_CLOSE(sqrt(3.14159265358979323846264338327950288419716939937510L/2), (root_half_pi<real_concept, Policy>)(), 2);
CHECK_ULP_CLOSE(sqrt(3.14159265358979323846264338327950288419716939937510L * 2), (root_two_pi<real_concept, Policy>)(), 2);
@@ -902,6 +915,7 @@ void test_real_concept_policy(const Policy&)
CHECK_ULP_CLOSE(1 / (3.14159265358979323846264338327950288419716939937510L), (one_div_pi<real_concept, Policy>)(), 2);
CHECK_ULP_CLOSE(2 / (3.14159265358979323846264338327950288419716939937510L), (two_div_pi<real_concept, Policy>)(), 2);
CHECK_ULP_CLOSE(1 / (2 * 3.14159265358979323846264338327950288419716939937510L), (one_div_two_pi<real_concept, Policy>)(), 2);
CHECK_ULP_CLOSE(log(3.14159265358979323846264338327950288419716939937510L), (log_pi<real_concept, Policy>)(), 2);
CHECK_ULP_CLOSE(sqrt(3.14159265358979323846264338327950288419716939937510L), (root_pi<real_concept, Policy>)(), 2);
CHECK_ULP_CLOSE(sqrt(3.14159265358979323846264338327950288419716939937510L / 2), (root_half_pi<real_concept, Policy>)(), 2);
CHECK_ULP_CLOSE(sqrt(2 * 3.14159265358979323846264338327950288419716939937510L), (root_two_pi<real_concept, Policy>)(), 2);