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Merge pull request #564 from boostorg/nct_fixes

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Fix up non-central T test data for 128-bit floats.
This commit is contained in:
jzmaddock
2021-03-09 12:11:04 +00:00
committed by GitHub
parent 7b270fc5f0 9c40b89aa9
commit 65fbd06cba
7 changed files with 640 additions and 312 deletions
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12
include/boost/math/special_functions/gamma.hpp
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@@ -1555,9 +1555,17 @@ T tgamma_delta_ratio_imp_lanczos(T z, T delta, const Policy& pol, const Lanczos&
T result;
if(z + delta == z)
{
if(fabs(delta) < 10)
result = exp((constants::half<T>() - z) * boost::math::log1p(delta / zgh, pol));
if (fabs(delta / zgh) < boost::math::tools::epsilon<T>())
{
// We have:
// result = exp((constants::half<T>() - z) * boost::math::log1p(delta / zgh, pol));
// 0.5 - z == -z
// log1p(delta / zgh) = delta / zgh = delta / z
// multiplying we get -delta.
result = exp(-delta);
}
else
// from the pow formula below... but this may actually be wrong, we just can't really calculate it :(
result = 1;
}
else