Here is a snapshot of the hierarchy I used in VW several years ago.

[image: Capture d’écran 2020-05-04 à 21.11.17.png]
It is in cincom store SYSEXT-RawArray
Unlike squeak, I have used single-byte elements uniformly.
VW only provide 8(byte) and 16(word) bits elements, so there is not much to
gain in complexifying the interface.
I did use Float and Double rather than Float32 and Float64 to fit what is
in a VW image. For the rest, just int and uint...
I might re-create a similar hierarchy in STEM, but I would prefer to see a
good one in the base image. That's useful for everyone.

Le lun. 4 mai 2020 à 09:29, K K Subbu <kksubbu.ml at gmail.com> a écrit :

> On 03/05/20 7:22 pm, Nicolas Cellier wrote:
> > More than often, the data transfer can handle offset and stride via a
> > BitBlt tricks (unless we have an odd layout).
> > This enables extracting a single "column" or bloc of data from a big
> > file with a single copy.
> > I may need to extend BitBlt to cope with all the available bit-widths,
> > not just 8 (byte) or 32 (word) though.
> >
> > Also, those formats offer packed and contiguous memory layout which is
> > an advantage too when dealing with large chunks of data.
> > Especially if we have vectorized primitives operating on the arrays.
> Ha! Now I get it. But FixedWidthBitArray is too primitive a type for
> this purpose. It would expose host's word size to class methods instead
> of encapsulating it in plugins.
>
> I would apply recursive decomposition and use something like
> PackedVector(stride, length) on the lines of a Form(width, height).
> PackedVectors may decomposed into smaller packedvectors recursively
> until they are small enough for ImmediateClass (i.e. stride = host's
> word size). This would be well-suited to speed up through arch-specific
> plugins.
>
> When loading a packedvector from an image on a smaller word size host,
> ImmediateClass elements could be converted into packedvectors. The
> reverse could happen on larger word size hosts with a one-time
> conversion cost.
>
> Regards .. Subbu
>
>
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