[Jprogramming] histogram in stats/base

[Devon McCormick]

I have noticed some oddities here too but mostly have ignored them and
adjusted my plots to compensate.  I mostly use my own variant
"plotHistoMulti" - here:
https://code.jsoftware.com/wiki/User:Devon_McCormick/myStats - but have not
yet nailed down exactly what is off with the underlying.

On Sat, Apr 10, 2021 at 12:13 AM Gilles Kirouac <g1201 at myriade.ca> wrote:

>
>     About the histogram verb in stats/base
>
> NB. The result is a list of counts of the number of data points in each
> interval.
>
>    Intervals are specified by the left argument. histogram uses dyadic I.
>
>     The I. primitive defines (1+#x) intervals. See its clear definition
> in Nuvoc. In short, it reports the index of the interval of the
> corresponding data value.
>
>     The primitive implies both __ and _ limits:
>
>        _5 0 5 I. _2 _7 0 3 9
> 1 0 1 2 3
>
>     But histogram does not always correctly report on the last interval:
>
>     _5 0 5 histogram _2 _7 0 3 9
> 1 2 1 0
>
>     Where has the last y value been classified? Five values were passed,
> but only four counted.
>
>     _5 0 5 _ histogram _2 _7 0 3 9 NB. OK
> 1 2 1 1
>
>    As currently defined, the interval defined by {:x must include the
> maximum value of y.
>
>    Apparently the current definition comes from the (old) Vocabulary in
> an example of dyadic I. But the definition there was appropriate for the
> given example (or vice-versa).
>
>    In a library, should we not have a more easily reliable tool? and
> with better symmetry.
>
> ~ Gilles
> ----------------------------------------------------------------------
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>


-- 

Devon McCormick, CFA

Quantitative Consultant