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Bug in cut() (mistakenly sent to "devel")

From: forkandwait
Subject: Bug in cut() (mistakenly sent to "devel")
Date: Mon, 5 Apr 2010 15:36:10 +0000 (UTC)
User-agent: Loom/3.14 (http://gmane.org/)

Hi all, I think there is a bug in cut() , or in its documentation.  Reading the
docs (second and third paras specifically -- see below), I would think it would
return only 1 & 2 and the rest NaNs in the example, but it also returns 0.  Why?

If someone could clarify how the intervals to cut are supposed to be shaped, I
would appreciate it. I would think like [ ) (closed on the minimum, open on the
max), but I can't figure this out...

This behavior might be an attempt to deal with the interval situation, but if so
it should be documented.  Likewise for ML compatibility.

If in fact this is a bug, I promise to send a patch with (1) new docs (2) a
bunch of tests added to cut(), and (perhaps) a fix.  

I am running 3.2.4, but I get the same error the 3.3.50 on my freebsd box


Supporting stuff -- first the cut help result, second some sample output, third
expected output:

## help cut

Function File:  cut (X, BREAKS)
     Create categorical data out of numerical or continuous data by
     cutting into intervals.

     If BREAKS is a scalar, the data is cut into that many equal-width
     intervals.  ***If BREAKS is a vector of break points, the category
     has `length (BREAKS) - 1' groups.***

     The returned value is a vector of the same size as X telling which
     group each point in X belongs to.  ***Groups are labelled from 1 to
     the number of groups***; points outside the range of BREAKS are
     labelled by `NaN'.

## output  
data = -1:6
breaks = [0 2 4]
cdata = cut(data, breaks)

octave-3.2.4.exe:11> [data', cdata']
ans =

    -1   NaN
     0     0                # this shouldn't be here
     1     1
     2     1
     3     2
     4     2
     5   NaN
     6   NaN

## I would expect the following, assuming [,) behavior:

-1  NaN
 0    1
 1    1
 2    2
 3    2
 4  NaN
 5  NaN
 6  NaN

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