From bug-request at octave dot org Thu Jan 27 10:38:21 2005
Subject: Re: dec2base
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Paul Kienzle <pkienzle at users dot sourceforge dot net>
Cc: Yassine Boujelben <yassine dot boujelben at polymtl dot ca>,         Andre Girard <andre@inrs-emt.uquebec.ca>, bug-octave@bevo.che.wisc.edu
Date: Thu, 27 Jan 2005 11:41:46 -0500

On  4-Jan-2005, Paul Kienzle <pkienzle at users dot sourceforge dot net> wrote:

| On Jan 3, 2005, at 3:58 PM, Yassine Boujelben wrote:
| 
| > I found the following bug in the dec2base function:
| > dec2base(1000,10)=000
| 
| Try the attached patch.
| 
| Paul Kienzle <pkienzle at users dot sf dot net>
| 	* strings/dec2base.m: Use integer arithmetic to count number of digits.

| Index: dec2base.m
| ===================================================================
| RCS file: /cvs/octave/scripts/strings/dec2base.m,v
| retrieving revision 1.4
| diff -c -p -r1.4 dec2base.m
| *** a/dec2base.m	29 Aug 2003 17:09:38 -0000	1.4
| --- b/dec2base.m	5 Jan 2005 04:44:29 -0000
| *************** function retval = dec2base (n, base, len
| *** 74,80 ****
|     endif
|     
|     ## determine number of digits required to handle all numbers
| !   max_len = floor (log (max (max (n), 1)) ./ log (base)) + 1;
|   
|     if (nargin == 3)
|       max_len = max (max_len, len);
| --- 74,82 ----
|     endif
|     
|     ## determine number of digits required to handle all numbers
| !   max_n = max(max(n),1);
| !   max_len = ceil(log(max_n)/log(base));
| !   if (base^max_len <= max_n) max_len++; endif
|   
|     if (nargin == 3)
|       max_len = max (max_len, len);
| *************** function retval = dec2base (n, base, len
| *** 89,91 ****
| --- 91,119 ----
|     retval = reshape (symbols (digits+1), size (digits));
|   
|   endfunction
| + 
| + %!test
| + %! s0='';
| + %! for n=1:13
| + %!   for b=2:16
| + %!     pp=dec2base(b^n+1,b);
| + %!     assert(dec2base(b^n,b),['1',s0,'0']);
| + %!     assert(dec2base(b^n+1,b),['1',s0,'1']);
| + %!   end
| + %!   s0=[s0,'0'];
| + %! end
| + 
| + %!test
| + %! digits='0123456789ABCDEF';
| + %! for n=1:13
| + %!   for b=2:16
| + %!     pm=dec2base(b^n-1,b);
| + %!     assert(length(pm),n);
| + %!     assert(all(pm==digits(b)));
| + %!   end
| + %! end
| + 
| + %!test
| + %! for b=2:16
| + %!   assert(dec2base(0,b),'0');
| + %! end

I applied this change.

Thanks,

jwe



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