From help-octave-request at bevo dot che dot wisc dot edu Sat Jan 25 15:12:50 2003
Subject: Why is sscanf() so slow?
From: stefan <stefan at lkcc dot org>
To: help-octave at bevo dot che dot wisc dot edu
Date: Sat, 25 Jan 2003 14:45:39 -0600

Dear Octaver's,

first of all:  Thanks for great software.  I am using it now for about two
years, especialy for displaying and adjusting measured data (comes from
some measurement bus system to computer).  The software which drives these
devices almostly always produce tab- or comma-seperated data.

For this I do:

    while (isstr(line = fgets(fid)))
      if (index(line, "#") == 1)
        continue;
      endif
      if (length(line) <= 2)
        continue;
      endif
      numbers = sscanf(line, "%g %g %g %g %g %g %g %g", 8);
      for i = 1 : length(numbers)
        values(n, i) = numbers(i);
      endfor
      n = n + 1;
    endwhile

or very likely...

For more than 1000 lines this takes *ages*.  Is there a better way to do
so or is it a slow implementation in octave?  I would like to see this
improved some day.

For now I do 'save -mat-binary %s values' to keep loading times short next
time.  Some cache algo around the above code.

Any help is appreciated,
	stefan at lkcc dot org



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