[Gcl-devel] Re: [Maxima] Maxima rationals compared to CL rationals

[Camm Maguire]

Greetings!

Just FYI ---

gcl
GCL (GNU Common Lisp)  2.6.8 CLtL1    Jul  4 2007 16:45:08
Source License: LGPL(gcl,gmp), GPL(unexec,bfd,xgcl)
Binary License:  GPL due to GPL'ed components: (XGCL READLINE BFD UNEXEC)
Modifications of this banner must retain notice of a compatible license
Dedicated to the memory of W. Schelter

Use (help) to get some basic information on how to use GCL.
Temporary directory for compiler files set to /tmp/

>(defun h (n)
  (let ((acc 0))
    (dotimes (i n acc)
      (setq acc (+ acc (/ 1 (+ 1 i)))))))

H

>(compile 'h)

Compiling /tmp/gazonk_16089_0.lsp.
End of Pass 1.  
End of Pass 2.  
OPTIMIZE levels: Safety=0 (No runtime error checking), Space=0, Speed=3
Finished compiling /tmp/gazonk_16089_0.lsp.
Loading /tmp/gazonk_16089_0.o
start address -T 0x8644000 Finished loading /tmp/gazonk_16089_0.o
#<compiled-function H>
NIL
NIL

>(time (progn (h 5000) nil))

real time       :     12.820 secs
run-gbc time    :      6.510 secs
child run time  :      0.000 secs
gbc time        :      0.390 secs
NIL

>
GCL_ANSI=t gclcvs
GCL (GNU Common Lisp)  2.7.0 ANSI    Jul 18 2007 10:48:57
Source License: LGPL(gcl,gmp,pargcl), GPL(unexec,bfd,xgcl)
Binary License:  GPL due to GPL'ed components: (XGCL READLINE BFD UNEXEC)
Modifications of this banner must retain notice of a compatible license
Dedicated to the memory of W. Schelter

Use (help) to get some basic information on how to use GCL.

Temporary directory for compiler files set to /tmp/

>(defun h (n)
  (let ((acc 0))
    (dotimes (i n acc)
      (setq acc (+ acc (/ 1 (+ 1 i)))))))

H

>(compile 'h)

;; Compiling /tmp/gazonk_16375_0.lsp.
;; End of Pass 1.  
;; End of Pass 2.  
;; OPTIMIZE levels: Safety=0 (No runtime error checking), Space=0, Speed=3, 
(Debug quality ignored)
;; Finished compiling /tmp/gazonk_16375_0.o.
;; Loading /tmp/gazonk_16375_0.o
 ;; start address -T 0xaa5d88 ;; Finished loading /tmp/gazonk_16375_0.o
#<compiled-function H>
NIL
NIL

>(time (progn (h 5000) nil))

real time       :      0.080 secs
run-gbc time    :      0.010 secs
child run time  :      0.000 secs
gbc time        :      0.070 secs
NIL

Take care,


Barton Willis <address@hidden> writes:

> Which function will compute 1 + 1/2 + ... + 1/5000 the fastest?
> 
> ;; Use Maxima rational numbers with add & div.
> 
> (defun $harmonic (n)
>   (let ((acc 0))
>     (dotimes (i n acc)
>       (setq acc (add acc (div 1 (+ 1 i)))))))
> 
> ;; Use CL rationals with + and /.
> 
> (defun $harmonic2 (n)
>   (let ((acc 0))
>     (dotimes (i n (cl-rat-to-maxima acc))
>       (setq acc (+ acc (/ 1 (+ 1 i)))))))
> 
> Using GCL, I get
> 
> (%i1) load("harmonic.o")$
> 
> (%i2) harmonic(5000)$
> Evaluation took 0.19 seconds (0.19 elapsed)
> 
> (%i3) harmonic2(5000)$
> Evaluation took 19.89 seconds (19.89 elapsed)
> 
> Is this due to fast code in addk? Or is GCL just slow
> with rational addition and division? Or something else?
> What's the story?
> 
> Barton
> _______________________________________________
> Maxima mailing list
> address@hidden
> http://www.math.utexas.edu/mailman/listinfo/maxima
> 
> 
> 

-- 
Camm Maguire                                            address@hidden
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"The earth is but one country, and mankind its citizens."  --  Baha'u'llah