Custom Query (1030 matches)

it once did, for reasons having to do with how subprimitives were called. see <​https://lists.clozure.com/pipermail/openmcl-devel/2016-February/011196.html>

The *default-external-format* doesn't considered by count-characters-in-octet-vector, decode-string-from-octets, encode-string-to-octets, string-size-in-octets functions which has the :external-format parameter.

There are patch suggested by Ron Garret:

(in-package :ccl)

(let ((ccl::*warn-if-redefine-kernel* nil))
  (defun lookup-character-encoding (name)
    (gethash (or name *default-external-format*) *character-encodings*)))

A colleague noticed that the following function can run more slowly with a suitable type declaration. I've reproduced his results on Linux:

Welcome to Clozure Common Lisp Version 1.12-dev-r16729M-trunk (LinuxX8664)!

Here are the commands:

(declaim (OPTIMIZE (COMPILATION-SPEED 0) (DEBUG 0) (SPEED 3) (SPACE 0) (SAFETY 0)))
(defun fibonacci (n)
  (declare (type (integer 0 *) n))
  (if (= n 0)
      0
    (if (= n 1)
        1
      (+ (fibonacci (- n 1)) (fibonacci (- n 2))))))

Then:

? (time (fibonacci 38))
(FIBONACCI 38)
took 912,371 microseconds (0.912371 seconds) to run.
During that period, and with 8 available CPU cores,
     912,812 microseconds (0.912812 seconds) were spent in user mode
         804 microseconds (0.000804 seconds) were spent in system mode
 1 minor page faults, 0 major page faults, 0 swaps.
39088169
? 

But here we see the time cut in more than half when we remove the type declaration:

? (time (fibonacci 38))
(FIBONACCI 38)
took 383,980 microseconds (0.383980 seconds) to run.
During that period, and with 8 available CPU cores,
     382,068 microseconds (0.382068 seconds) were spent in user mode
       2,433 microseconds (0.002433 seconds) were spent in system mode
 1 minor page faults, 0 major page faults, 0 swaps.
39088169
?