[Cuis-dev] On ArrayedCollection >> incrementFraction

[Luciano Notarfrancesco]

Hi Pancho,
Is it really more efficient? I think the idea of the original is to take
advantage of the bulk primitives in Float32Array and Float64Array, it
should be much faster (Although it contains a superfluous copy, it could be
improved a bit).

On Wed, May 13, 2026 at 19:31 Francisco Garau via Cuis-dev <
cuis-dev at lists.cuis.st> wrote:

> I've prepared a more generic and efficient implementation of these methods
> (with a small difference in behavior) -- I would prefer to submit this
> changes with a couple of PRs (one for the base image and one for the
> numerical package). Appreciate if there is any documentation for new
> contributions.
>
> #( 3 5 8 ) successiveRatios = { 1. 5/3 . 8/5} ." -- currently the first
> element is always 1 -- "
> #( 3 5 8 ) successiveRatios = { 5/3 . 8/5} . " -- the ratios will be
> calculated in between pairs --"
>
> *ArrayedCollection >> successiveRatios*
>
> "
> #( 3 5 8 ) successiveRatios = {5/3 . 8/5}.
> ([#(3) successiveRatios] on: Error do: [:ex | ex description ] ) = 'Error:
> this collection is too small'.
> "
> ^self collectSlidingWindow: [:a :b | b / a ]
>
>
>
> *SequenceableCollection >> collectSlidingWindow: aBlock*
>
> "
> (#( 3 5 8 13 ) collectSlidingWindow: [:a :b | a at b]) = {3 at 5 . 5 at 8 . 8 at 13}.
> (#( 3 5 8 13 ) collectSlidingWindow: [:a :b :c | {a. b. c}]) = {{3. 5. 8}.
> {5. 8. 13.}}.
> ('hello_word'  collectSlidingWindow: [:a | Character codePoint: a
> codePoint - 32]) = 'HELLO?WORD'.
>
> ([#(3) collectWithSlidingWindow: [:a :b | a + b]] on: Error do: [:ex | ex
> description]) = 'Error: this collection is too small'.
> "
> |  tupleSize newSize answer  blockArgs |
> tupleSize := aBlock numArgs.
> self size < tupleSize ifTrue: [self errorCollectionTooSmall].
> newSize := self size - tupleSize + 1.
> answer := self species new: newSize.
> blockArgs := Array new: tupleSize.
> 1 to: newSize do: [ :i |
> 1 to: tupleSize do: [:m | blockArgs at: m put: (self at: i + m -1 )].
> answer at: i put: (aBlock valueWithArguments: blockArgs).].
> ^ answer
>
>
>
> On Mon, 11 May 2026 at 20:12, Juan Vuletich via Cuis-dev <
> cuis-dev at lists.cuis.st> wrote:
>
>> Hi Ezequiel,
>>
>> (inline)
>> On 2026-05-03 1:48 AM, Ezequiel Birman via Cuis-dev wrote:
>>
>> Hi!,
>>
>> 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:
>>
>> incrementFraction
>>> "
>>> #(10 12.5 15 20) incrementFraction
>>> "
>>> | displaced answer |
>>> displaced := self class new: self size.
>>> displaced replaceFrom: 2 to: self size with: self startingAt: 1.
>>> displaced at: 1 put: self first.
>>> answer := self copy.
>>> answer -= displaced.
>>
>> ^answer / displaced
>>
>>
>> derivative
>>> | displaced answer |
>>> displaced := self class new: self size.
>>> displaced replaceFrom: 2 to: self size with: self startingAt: 1.
>>> displaced at: 1 put: self first - self first. "Some reasonable zero"
>>> answer := self copy.
>>> answer -= displaced.
>>> ^answer
>>
>>
>> I think I want something similar, except for the subtraction:
>>
>>> myThing
>>>
>>> | displaced answer |
>>> displaced := self class new: self size.
>>> displaced replaceFrom: 2 to: self size with: self startingAt: 1.
>>> displaced at: 1 put: self first.
>>> answer := self copy.
>>
>> ^answer / displaced
>>
>>
>> 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.
>>
>> This makes a lot of sense. I've just added your method with selector
>> #successiveRatios and your author initials. Thanks!
>>
>>
>> Neither `derivative` nor `incrementFraction` nor `Integral` have senders.
>> Juan, maybe you remember why or under which circumstances you added them in
>> 2024?
>>
>> 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.
>>
>>  Are there any efforts / packages for numeric or data analysis?
>>
>>
>> Not specifically for that, but a good place for it would be
>> https://github.com/Cuis-Smalltalk/Numerics
>>
>> Cheers,
>>
>>
>> --
>> Eze
>>
>> --
>> Juan Vuletichwww.cuis.stgithub.com/jvuletichresearchgate.net/profile/Juan-Vuletichindependent.academia.edu/JuanVuletichpatents.justia.com/inventor/juan-manuel-vuletich
>>
>> --
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>>
> --
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