About JEP 338: Vector API

[b.lacombe at lug.com]

About JEP 338: Vector API

A)  you write :
-----
static final VectorSpecies<Float> SPECIES = FloatVector.SPECIES_256;

void vectorComputation(float[] a, float[] b, float[] c) {

 
    for (int i = 0; i < a.length; i += SPECIES.length()) {
        var m = SPECIES.indexInRange(i, a.length);
    // FloatVector va, vb, vc;
        var va = FloatVector.fromArray(SPECIES, a, i, m);
        var vb = FloatVector.fromArray(SPECIES, b, i, m);
        var vc = va.mul(va).
                    add(vb.mul(vb)).
                    neg();
        vc.intoArray(c, i, m);
    }
}
-----
It is very complexe source code to write a simple (a*a+b )*-1

It 'll more easy, if we can write :
        FloatVector.forAll(a).mul(a).add(b).neg().toArray(c)
Where each operator (mul,add,neg) can make the convertion :
        var va=>FloatVector.fromArray(SPECIES, a, i, m) ...
Of course optimisation can be done  with a code like :
----
        void mul(a, ... buf){
                var va = cache.get(a);
                if( va==nul ){
                        va =  FloatVector.fromArray(SPECIES, a, i, m);
                        cache.put(a,va);
                }
                //here va
                .....
        }
----

2) A another optimisation can be make by preparing data  whith a "width" 
operator like :
        FloatVector
                .width(a,b,c)
                .forAll(a)
                .mul(a).add(b).neg()
                .toArray(c);
then source is more easy to read, and less complex 
what did you think ?


3) And if we can upgrade java grammar, a code like this for matrix :
                c = FloatVector[[ a*a+b*-1 ]] 
would be ecxellent (where a,b,c must be final array) and so easy ....







Cordialement

Bruno LACOMBE
Multimédia SOLUTIONS
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