From bug-octave-request at bevo dot che dot wisc dot edu  Sat May 13 01:01:41 2000
Subject: strrep speedup
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: pkienzle at kienzle dot powernet dot co dot uk (Paul Kienzle)
Cc: bug-octave at bevo dot che dot wisc dot edu
Date: Sat, 13 May 2000 01:03:50 -0500 (CDT)

On 12-May-2000, Paul Kienzle <pkienzle at kienzle dot powernet dot co dot uk> wrote:

| To: bug-octave at bevo dot che dot wisc dot edu
| Cc: pkienzle
| Subject: strrep speedup
| 
| Bug report for Octave 2.0.13 configured for i386-pc-linux-gnu
| 
| Description:
| -----------
| 
| speedups for strrep.  Break-even by 3 replacements, hundreds of times
| faster for many, many replacements.
| 
| Repeat-By:
| ---------
| 
| octave> s=blanks(2000); t=time(); strrep(s," ", "y"); time()-t
| ans = 0.027692
| octave> s=blanks(2000); t=time(); strrep_orig(s," ", "y"); time()-t
| ans = 6.Fix

I applied this patch with one additional change.  I removed

      if (size(s,1) == 1)
	t = t';
      endif

in the section jump > 0.  Otherwise, I see

  octave:18> strrep ("abbc", "bb", "X")
  ans = aXc
  octave:19> strrep ("abbc", "bb", "XX")
  ans = aXXc
  octave:20> strrep ("abbc", "bb", "XXX")
  t = abbc
  ans =

  a
  X
  X
  X
  c

Can you please explain if the transpose is really needed for some
other case?

Thanks,

jwe



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