[Octave-bug-tracker] [bug #53199] hist returns different results depending on 2nd 1:n/n input argument

[Rik]

Update of bug #53199 (project octave):

                  Status:                    None => Works For Me           

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Follow-up Comment #1:

There is a difference between the two calling syntaxes.  When you call hist
with a vector you directly set the bin centers.  When you call hist with just
the number of bins to use it determines the bin centers based on the range of
the data.  The two are not the same.  Use the second output argument to see
the calculated bin centers.  Try the following code:


a = [  1,  2,  3,  4, 0;
       5,  4,  6,  7, 8;
       9, 12, 11, 10, 0;
      13, 16, 15, 14, 0;
      17, 20, 19, 18, 0;
      21, 22, 23,  2, 0;
      24, 27, 26, 25, 0;
      28, 31, 30, 29, 0;
      32, 35, 34, 33, 0;
      36, 39, 38, 37, 0;
      40, 43, 42, 41, 0;
      44, 47, 46, 45, 0;
      48, 51, 50, 49, 0;
      52, 55, 54, 53, 0];
a = a(:);
b = min (a)
n = max(a)
[cnt1, ctr1] = hist(a, 1:n);
ctr1
[cnt2, ctr2] = hist(a, n);
ctr2


In Octave this produces


octave:19> diary on
octave:20> a = [  1,  2,  3,  4, 0;
>        5,  4,  6,  7, 8;
>        9, 12, 11, 10, 0;
>       13, 16, 15, 14, 0;
>       17, 20, 19, 18, 0;
>       21, 22, 23,  2, 0;
>       24, 27, 26, 25, 0;
>       28, 31, 30, 29, 0;
>       32, 35, 34, 33, 0;
>       36, 39, 38, 37, 0;
>       40, 43, 42, 41, 0;
>       44, 47, 46, 45, 0;
>       48, 51, 50, 49, 0;
>       52, 55, 54, 53, 0];
octave:21> a = a(:);
octave:22> b = min (a)
b = 0
octave:23> n = max(a)
n =  55
octave:24> [cnt1, ctr1] = hist(a, 1:n);
octave:25> ctr1
ctr1 =

 Columns 1 through 19:

    1    2    3    4    5    6    7    8    9   10   11   12   13   14   15  
16   17   18   19

 Columns 20 through 38:

   20   21   22   23   24   25   26   27   28   29   30   31   32   33   34  
35   36   37   38

 Columns 39 through 55:

   39   40   41   42   43   44   45   46   47   48   49   50   51   52   53  
54   55

octave:26> [cnt2, ctr2] = hist(a, n);
octave:27> ctr2
ctr2 =

 Columns 1 through 8:

    0.50000    1.50000    2.50000    3.50000    4.50000    5.50000    6.50000 
  7.50000

 Columns 9 through 16:

    8.50000    9.50000   10.50000   11.50000   12.50000   13.50000   14.50000 
 15.50000

 Columns 17 through 24:

   16.50000   17.50000   18.50000   19.50000   20.50000   21.50000   22.50000 
 23.50000

 Columns 25 through 32:

   24.50000   25.50000   26.50000   27.50000   28.50000   29.50000   30.50000 
 31.50000

 Columns 33 through 40:

   32.50000   33.50000   34.50000   35.50000   36.50000   37.50000   38.50000 
 39.50000

 Columns 41 through 48:

   40.50000   41.50000   42.50000   43.50000   44.50000   45.50000   46.50000 
 47.50000

 Columns 49 through 55:

   48.50000   49.50000   50.50000   51.50000   52.50000   53.50000   54.50000

octave:28> diary off



Could you try the same code in Matlab and also report the version of Matlab
you are using?  Octave used to be Matlab compatible, but I notice they are now
trying to deprecate the hist() function and move to the histogram function
instead.


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