Lockstep iteration in parallel: Error: cannot have parameter of type `void`

[kdevel]

Thanks for your explications!

On Friday, 19 May 2023 at 21:18:28 UTC, Ali Çehreli wrote:
> [...]
> - std.range.zip can be used instead but it does not provide 
> 'ref' access to its elements.

How/why does sort [1] work with zipped arrays?

> [...]
>
> The following amap example there may be useful for your case 
> but I could not make the types work:

Do you mean using the function pointer does not work?

> // Same thing, but explicitly allocate an array
> // to return the results in.  The element type
> // of the array may be either the exact type
> // returned by functions or an implicit conversion
> // target.
> auto squareRoots = new float[numbers.length];
> taskPool.amap!sqrt(numbers, squareRoots);

This even seems to work with a static function pointer:

    int main ()
    {
       import std.stdio;
       import std.math;
       import std.parallelism;

       const double [] a = [1., 2., 3., 4.];
       double [] b = [0., 0., 0., 0.];

       writeln (a);
       writeln (b);

       double function (double) fp = &sqrt;
       taskPool.amap!fp (a, b);

       writeln (a);
       writeln (b);
       return 0;
    }

Using an automatic variable gives a deprecation warning

    main.amap!(const(double)[], double[]).amap` function requires a
    dual-context, which is deprecated

[1] https://dlang.org/library/std/range/zip.html