This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "OCT: A portable Lisp implementation for quad-double precision floats". The branch, master has been updated via 08d254374188f97026d114451bba5d839dbdad11 (commit) from c31b1cdd112f26334b7762014d3afb781917ebda (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 08d254374188f97026d114451bba5d839dbdad11 Author: Raymond Toy <toy.raymond@gmail.com> Date: Mon Mar 28 22:54:32 2011 -0400 Make INCOMPLETE-GAMMA-TAIL more accurate. o Use the new continued fraction for the incomplete-gamma when the argument z is close enough to the negative real axis. diff --git a/qd-gamma.lisp b/qd-gamma.lisp index e020a91..7048b80 100644 --- a/qd-gamma.lisp +++ b/qd-gamma.lisp @@ -372,8 +372,15 @@ (if (and (> (abs z) (abs (- a 1))) (not (minusp (realpart z)))) (cf-incomplete-gamma-tail a z) - (- (gamma a) (incomplete-gamma a z))) - (cf-incomplete-gamma-tail a z)))) + (- (gamma a) (cf-incomplete-gamma a z))) + ;; If the argument is close enough to the negative real axis, + ;; the continued fraction for the tail is not very accurate. + ;; Use the incomplete gamma function to evaluate in this + ;; region. (Arbitrarily selected the region to be a sector. + ;; But what is the correct size of this sector?) + (if (<= (phase z) 3.1) + (cf-incomplete-gamma-tail a z) + (- (gamma a) (cf-incomplete-gamma a z)))))) (defun incomplete-gamma (a z) "Incomplete gamma function defined by: ----------------------------------------------------------------------- Summary of changes: qd-gamma.lisp | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) hooks/post-receive -- OCT: A portable Lisp implementation for quad-double precision floats