devtools/eigen
1
0
Fork 0
mirror of https://gitlab.com/libeigen/eigen.git synced 2026-04-10 11:34:33 +08:00
Code Issues Packages Projects Releases Wiki Activity

Exponentially scaled modified Bessel functions of order zero and one.

Browse Source 
The functions are conventionally called i0e and i1e. The exponentially scaled version is more numerically stable. The standard Bessel functions can be obtained as i0(x) = exp(|x|) i0e(x)

The code is ported from Cephes and tested against SciPy.
This commit is contained in:
Michael Figurnov
2018-05-31 15:34:53 +01:00
parent 6af1433cb5
commit f216854453
12 changed files with 731 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
unsupported/Eigen/src/SpecialFunctions/SpecialFunctionsPacketMath.h
View File

@@ -50,6 +50,18 @@ Packet pigammac(const Packet& a, const Packet& x) { using numext::igammac; retur
template<typename Packet> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
Packet pbetainc(const Packet& a, const Packet& b,const Packet& x) { using numext::betainc; return betainc(a, b, x); }
/** \internal \returns the exponentially scaled modified Bessel function of
* order zero i0e(\a a) (coeff-wise) */
template <typename Packet>
EIGEN_DEVICE_FUNC EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
Packet pi0e(const Packet& x) { using numext::i0e; return i0e(x); }
/** \internal \returns the exponentially scaled modified Bessel function of
* order one i1e(\a a) (coeff-wise) */
template <typename Packet>
EIGEN_DEVICE_FUNC EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
Packet pi1e(const Packet& x) { using numext::i1e; return i1e(x); }
} // end namespace internal
} // end namespace Eigen