From help-octave-request at bevo dot che dot wisc dot edu Thu Jan 23 00:16:22 2003
Subject: Re: How to input tabular data through a form? (fwd)
From: "Dmitri A. Sergatskov" <dima at coffee dot phys dot unm dot edu>
To: help-octave <help-octave at bevo dot che dot wisc dot edu>
Date: Wed, 22 Jan 2003 23:16:06 -0700 (MST)

Oops, forgot to CC to the list.

---------- Forwarded message ----------
Date: Wed, 22 Jan 2003 23:12:17 -0700 (MST)
From: Dmitri A. Sergatskov <dima at coffee dot phys dot unm dot edu>
To: Paul Kienzle <pkienzle at users dot sf dot net>
Subject: Re: How to input tabular data through a form?

Paul,

Just for fun I timed your dlmread vs straight fscanf on a rather  
large file (did 3 times to see if there cache related effects):

--------
GNU Octave, version 2.1.42 (i686-pc-linux-gnu).
....
gnuplot_binary = /usr/local/bin/gnuplot
octave:1> tic ; a=dlmread('tmp2.dat') ; toc
ans = 125.80
octave:2> tic ; a=dlmread('tmp2.dat') ; toc
ans = 126.94
octave:3> tic ; a=dlmread('tmp2.dat') ; toc
ans = 126.73
octave:4> tic; fid=fopen('tmp2.dat'); a=fscanf(fid,'%f,%f,%f,%f,%f,%f,%f,%f,%f,%f',[10,inf]); fclose(fid); toc
ans = 23.869
octave:5> tic; fid=fopen('tmp2.dat'); a=fscanf(fid,'%f,%f,%f,%f,%f,%f,%f,%f,%f,%f',[10,inf]); fclose(fid); toc
ans = 23.518
octave:6> tic; fid=fopen('tmp2.dat'); a=fscanf(fid,'%f,%f,%f,%f,%f,%f,%f,%f,%f,%f',[10,inf]); fclose(fid); toc
ans = 23.485

[dima at psyche t4c-8]$ ls -lh tmp2.dat
-rw-rw-r--    1 dima     dima          63M Jan 22 22:48 tmp2.dat
[dima at psyche t4c-8]$
----------------

I understand that dlmread does quite a few things, but frankly I was surprised
that difference is so large. I suspect it is mostly due to 'reshape', 
but have not done any actual profiling. 

Sincerely,

Dmitri.
 







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