[Cuis-dev] On ArrayedCollection >> incrementFraction

[Francisco Garau]

Ahh.. I've missed those optimisations in the FloatArray classes.

It needs a bit more work if we were to keep those optimizations.

For me it was more an exercise in using Cuis than solving an actual problem.


On Wed, 13 May 2026 at 14:31, Luciano Notarfrancesco via Cuis-dev <
cuis-dev at lists.cuis.st> wrote:

> 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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