<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<p>Hi Ezequiel,</p>
<p>(inline)</p>
<div class="moz-cite-prefix">On 2026-05-03 1:48 AM, Ezequiel Birman
via Cuis-dev wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAOo=t4c+n14s6vQbpZUpbV1Kh6ZHGAq66g9SXwOa9L3UkpQ6ng@mail.gmail.com">Hi!,<br>
<br>
I want to collect the successive ratios in a collection of numbers
in order to appreciate how “fast” they grow. I noticed that the
image already implements ArrayedCollection >>
incrementFraction, which is almost equal to ArrayedCollection
>> derivative:<br>
<br>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">incrementFraction<br>
"<br>
#(10 12.5 15 20) incrementFraction<br>
"<br>
| displaced answer |<br>
displaced := self class new: self size.<br>
displaced replaceFrom: 2 to: self size with: self startingAt: 1.<br>
displaced at: 1 put: self first.<br>
answer := self copy.<br>
answer -= displaced. </blockquote>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">^answer
/ displaced</blockquote>
<div><br>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">derivative<br>
| displaced answer |<br>
displaced := self class new: self size.<br>
displaced replaceFrom: 2 to: self size with: self startingAt:
1.<br>
displaced at: 1 put: self first - self first. "Some reasonable
zero"<br>
answer := self copy.<br>
answer -= displaced.<br>
^answer </blockquote>
</div>
<div><br>
</div>
<div>I think I want something similar, except for the
subtraction: </div>
<div>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">myThing<br>
<br>
| displaced answer |<br>
displaced := self class new: self size.<br>
displaced replaceFrom: 2 to: self size with: self startingAt:
1.<br>
displaced at: 1 put: self first.<br>
answer := self copy. </blockquote>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">^answer
/ displaced</blockquote>
<div><br>
I'll probably need both, since I'm doing exploratory analysis.
And while `myThing`, (which could be named `successiveRatios`
or something along those lines) can answer if there is a
constant or varying growth, `incrementFraction` measures the
rate at which the growth itself is scaling.<br>
</div>
</div>
</blockquote>
<p>This makes a lot of sense. I've just added your method with
selector #successiveRatios and your author initials. Thanks!</p>
<blockquote type="cite"
cite="mid:CAOo=t4c+n14s6vQbpZUpbV1Kh6ZHGAq66g9SXwOa9L3UkpQ6ng@mail.gmail.com">
<div>
<div><br>
Neither `derivative` nor `incrementFraction` nor `Integral`
have senders. Juan, maybe you remember why or under which
circumstances you added them in 2024?</div>
</div>
</blockquote>
<p>I'd guess they are older than that. They are there because they
are ilustrative and could be of use. It is nice to have this kind
of stuff in the image. I believe it shows general Smalltalk-fu.</p>
<blockquote type="cite"
cite="mid:CAOo=t4c+n14s6vQbpZUpbV1Kh6ZHGAq66g9SXwOa9L3UkpQ6ng@mail.gmail.com">
<div>
<div> Are there any efforts / packages for numeric or data
analysis?<br>
</div>
</div>
</blockquote>
<p><br>
</p>
<p>Not specifically for that, but a good place for it would be
<a class="moz-txt-link-freetext" href="https://github.com/Cuis-Smalltalk/Numerics">https://github.com/Cuis-Smalltalk/Numerics</a></p>
<p>Cheers,</p>
<blockquote type="cite"
cite="mid:CAOo=t4c+n14s6vQbpZUpbV1Kh6ZHGAq66g9SXwOa9L3UkpQ6ng@mail.gmail.com">
<div>
<div><br>
-- <br>
Eze</div>
</div>
</blockquote>
<pre class="moz-signature" cols="72">--
Juan Vuletich
<a class="moz-txt-link-abbreviated" href="http://www.cuis.st">www.cuis.st</a>
github.com/jvuletich
researchgate.net/profile/Juan-Vuletich
independent.academia.edu/JuanVuletich
patents.justia.com/inventor/juan-manuel-vuletich</pre>
</body>
</html>