Re: How to sort a multidimensional ndslice?

[9il via Digitalmars-d-learn]

On Tuesday, 18 August 2020 at 13:07:56 UTC, Arredondo wrote:

On Tuesday, 18 August 2020 at 04:07:56 UTC, 9il wrote:

To reorder the columns data according to precomputed index:
auto index = a.byDim!1.map!sum.slice;

Hello Ilya, thanks for the answer!

Unfortunately I can't use it because I don't have (and can't define) a sorting index for my columns. I only have a predicate `larger(c1, c2)` that compares two columns to decide which one is "larger".

Cheers!
Armando.

This should work. But reallocates the data.

/+dub.sdl:
dependency "mir-algorithm" version="~>3.9.24"
+/
import std.stdio;

import mir.array.allocation;
import mir.ndslice;
import mir.ndslice.sorting;

void main() {
    auto a = [[1, -1, 3, 2],
              [0, -2, 3, 1]].fuse;

    writeln(a);
    auto b = a.byDim!1.array;
    b.sort!larger;
        auto c = b.fuse!1;
    writeln(c);
}

auto larger(C)(C u, C v) {
    import mir.math.sum : sum;
    return sum(u) > sum(v);
}