Question on Vector API and MemorySegment

[Bhateja, Jatin]

Hi Paul,  Aurelian,

We already have an enhancement request filed for this.

https://bugs.openjdk.org/browse/JDK-8320698

Best Regards,
Jatin

> -----Original Message-----
> From: panama-dev <panama-dev-retn at openjdk.org> On Behalf Of Paul Sandoz
> Sent: Saturday, May 4, 2024 3:43 AM
> To: Aurelian Tutuianu <padreati at yahoo.com>
> Cc: panama-dev at openjdk.org
> Subject: Re: Question on Vector API and MemorySegment
> 
> Hi Aurelian,
> 
> There was no explicit plan, but they should probably be added now that Foreign
> Function and Memory API is final (before that we were conservative adding
> memory segment access methods). Need a volunteer :-)
> 
> In theory we should be able to reuse the underlying storeWithMap intrinsic for
> indexed segment access. There is some degree of complexity wiring up segment
> accesses to be correctly scoped. Perhaps most of the work is adding tests. API-
> wise we would need to decide whether the index map should also be a segment
> with a long map offset, rather than an int[] array. I think it should be a segment,
> and it’s slightly more work to do that.
> 
> Paul.
> 
> 
> > On Apr 23, 2024, at 3:00 AM, Aurelian Tutuianu <padreati at yahoo.com> wrote:
> >
> > Hi everybody,
> >
> > I am using Vector API to manipulate arrays for linear algebra purposes with
> stride arrays. I was considering to use directly MemorySegment but I found some
> APIs that does not exist for MemorySegment, but there are for arrays. Those
> methods are for loading and storing from a MemorySegment using an index map.
> This is really useful for stride arrays. Below is an example of code:
> >
> > VectorSpecies<Double> vsd = DoubleVector.SPECIES_PREFERRED; int[]
> > indexes = new int[vsd.length()]; for (int i = 0; i < indexes.length;
> > i++) { indexes[i] = i * 2; }
> >
> > double[] array = new double[1000];
> > // read with index map elements 2 by 2 DoubleVector.fromArray(vsd,
> > array, 0, indexes, 0);
> >
> > MemorySegment ms = MemorySegment.ofArray(array); // no possible to
> > read with index map vsd.fromMemorySegment(ms, 0,
> > ByteOrder.nativeOrder());
> >
> >
> > Do you have in plan to implement those methods?
> >
> > Thanks for everything. Best regards,
> > Aurelian Tutuianu
>