Subject: Re: Q: (LispWorks) speed issue From: Erik Naggum <email@example.com> Date: Wed, 13 Mar 2002 18:12:42 GMT Newsgroups: comp.lang.lisp Message-ID: <firstname.lastname@example.org> * Nicolas Neuss | An even simpler possibility is to use floating point operations for | semi-long integers. Try the following: | | (defun tt (nn) | (declare (optimize (speed 3) (safety 0))) | (loop for k of-type double-float below (float nn 1.0d0) do | nil)) | | (time (tt 100000000)) Very good advice, only make sure that k and (1- k) are different, i.e., that you use fewer bits than the precision of the floating point format. (float-precision 1d0) returns that number. Of course, this works best when double-floats are not passed around, otherwise, they need to be boxed and cons like mad. It _should_ have been equally efficient with bignums, methinks. Oh, well. /// -- In a fight against something, the fight has value, victory has none. In a fight for something, the fight is a loss, victory merely relief.