News for R Package Bessel

Changes in version 0.7-0 (2026-01-07, svn r357)

New Features

• New bessJsmlNu(), to get J_\nu(x) for very small \nu; related to R-devel bug report for nu = 1e-15.

• besselJs(x, nu) got new switch use.log which is now automatically true for large (x/2)^nu, and allows e.g., besselJs(5, 999) to correctly return 0 instead of NaN.

• New incompleteBesselK() (calling C code) and incompleteBesselKR() pure R code, both from CRAN package DistributionUtils, donated by David Scott and Hassan Safouhi (in Sep. 2010, but never activated).

Changes in version 0.6-2 (2024-08-12, svn r325)

Misc

• .C(zbiry, ..) correctly now, thanks to Alexios Galanos.

Changes in version 0.6-1 (2024-07-29, svn r323)

New Features

• Using cospi(nu) instead of cos(pi*nu), for negative nu, both in BesselJ() and BesselY() may increase accuracy.

Bug Fixes

• Rd-crossrefs: replace \linkS4class{mpfr} by \link[Rmpfr:mpfr-class]{mpfr}.

Changes in version 0.6-0 (2019-04-24, svn r67)

SIGNIFICANT USER-VISIBLE CHANGES

• The exponential rescaling for the asymptotic version of the I() function has been changed (for non-real complex arguments) to be compatible to the scaling for BesselI().

New Features

• deprecate bI() to use besselIs() instead – enable log = TRUE option and test it.

• new besselJs(), i.e., Taylor series for J_n(x); using lssum() for alternating exp/log sum, also works with Rmpfr's mpfr() high precision numbers.

• use C routine registration, adding safety and a bit of speed.

• improved documentation for Bessel functions Ai,Bi, H, I,J,K,Y.

• besselI.nuAsym() and besselK.nuAsym() now allow maximal k.max = 5 (instead of 4).

• new besselKasym() (9.7.2 of A.&S. p.378).

• All the TOMS 644 routines get an optional argument verbose indicating the verbosity level of output notably from C code. The output itself may change and is not part of the API.

Bug Fixes

• fix BesselI(<cmplx>, nu < 0, expo..=TRUE) bug thanks to Hiroyuki Kawakatsu.

• better warning message (r29).

• the TOMS 644 routines Bessel[HIYJK] and Airy[AB] now all return NaN with a warning instead of stopping with an error in case of low level error ierr == 4.

• BesselK(0,*) is zero now, and BesselH(m, z=0,..) returns Inf/NaN combinations. Both no longer end with an error (from ierr == 1).

• BesselK(<negative>, 3) and BesselJ(*) now also return the correct imaginary part instead of just a numeric value.

• besselIs(z, nu) now also works for complex z.

Changes in version 0.5-5 (2013-12-10, svn r17)

Bug Fixes

• Adapt to new standard: move vignettes to own ‘vignettes/’ directory.

Changes in version 0.5-4 (2012-03-21, svn r16)

New Features

• Improved vignette

Bug Fixes

• BesselY(0, nu) should not give an error message from zbesy(), but either -Inf (real 0) or something like "Inf + NaN i".

• Cosmetic, mainly for R CMD check

Changes in version 0.5-3 (2009-12-22 – 2010-11-29, svn r8)

New Features

• besselI.nuAsym() and besselK.nuAsym() asymptotic versions for large nu and/or x

ALL PREVIOUS changes (version 0.0-0)

• See the ‘ChangeLog’ file in the sources.