Revert changes to std_falback::log1p that broke handling of arguments less than -1. Fix packet op accordingly.

This commit is contained in:
Rasmus Munk Larsen 2019-08-27 15:35:29 -07:00
parent b021cdea6d
commit 9aba527405
3 changed files with 2 additions and 7 deletions

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@ -550,9 +550,8 @@ namespace std_fallback {
EIGEN_USING_STD_MATH(log);
Scalar x1p = RealScalar(1) + x;
Scalar log_1p = log(x1p);
const bool is_inf = numext::equal_strict(x1p, log_1p);
const bool is_small = numext::equal_strict(x1p, Scalar(1));
return (is_inf || is_small) ? x : x * (log_1p / (x1p - RealScalar(1)));
return is_small ? x : x * (log_1p / (x1p - RealScalar(1)));
}
}

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@ -137,10 +137,8 @@ Packet generic_plog1p(const Packet& x)
Packet xp1 = padd(x, one);
Packet small_mask = pcmp_eq(xp1, one);
Packet log1 = plog(xp1);
// Add a check to handle x == +inf.
Packet pos_inf_mask = pcmp_eq(x, log1);
Packet log_large = pmul(x, pdiv(log1, psub(xp1, one)));
return pselect(por(small_mask, pos_inf_mask), x, log_large);
return pselect(small_mask, x, log_large);
}
/** \internal \returns exp(x)-1 computed using W. Kahan's formula.

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@ -607,8 +607,6 @@ template<typename Scalar,typename Packet> void packetmath_real()
CHECK_CWISE1_IF(internal::packet_traits<Scalar>::HasLGamma, std::lgamma, internal::plgamma);
CHECK_CWISE1_IF(internal::packet_traits<Scalar>::HasErf, std::erf, internal::perf);
CHECK_CWISE1_IF(internal::packet_traits<Scalar>::HasErfc, std::erfc, internal::perfc);
data1[0] = std::numeric_limits<Scalar>::infinity();
data1[1] = std::numeric_limits<Scalar>::denorm_min();
CHECK_CWISE1_IF(PacketTraits::HasExpm1, std::expm1, internal::pexpm1);
CHECK_CWISE1_IF(PacketTraits::HasLog1p, std::log1p, internal::plog1p);
#endif