Re: Problem Computing Dot Product with mir

[Kyle Ingraham via Digitalmars-d-learn]

On Monday, 22 February 2021 at 07:14:26 UTC, 9il wrote:
On Sunday, 21 February 2021 at 16:18:05 UTC, Kyle Ingraham 
wrote:
I am trying to convert sRGB pixel values to XYZ with mir using 
the following guide: 
http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html

[...]

mir-glas is deprecated experimental project. It is worth use 
mir-blas or lubeck instead. There is also naming issue. In the 
classic BLAS naming dot refers a function that accept two 1D 
vectors.

Your suggestion worked beautifully. I went with lubeck. I don't 
know how I missed it seeing that it is right there in the Dlang 
tour.

Thank you for writing such useful libraries.

Final code ended up being:

import std.stdio;

import kaleidic.lubeck: mtimes;
import mir.ndslice: as, byDim, fuse, map, sliced;

void main()
{
        auto rgbToXyz = [0.4124564,  0.3575761,  0.1804375,
                                         0.2126729,  0.7151522,  0.0721750,
                                         0.0193339,  0.1191920,  0.9503041]
                .as!double
                .sliced(3, 3);

        ubyte[] rgbPixels = [255, 0, 0,
                                                 0, 255, 0,
                                                 0, 0, 255,
                                                 120, 120, 120];

        auto xyzPixels = rgbPixels
                // convert input array elements to double - lazy
                .as!double
                // create a slice-shell over the input array
                .sliced(2, 2, 3)
                // normalize pixel channels to range [0, 1]
                .map!(chnl => chnl / 255.0)
                // sRGB inverse compand
		.map!(chnl => chnl <= 0.04045 ? chnl / 12.92 : ((chnl + 0.055) 
/ 1.055) ^^ 2.4)
                // linear RGB to XYZ
                // iterator by x and y over pixels (3rd dimension)
                .byDim!(0, 1) // same as .pack!1
                // dot product of each pixel with conversion matrix
                .map!(pixel => mtimes(rgbToXyz, pixel))
                // join iterator values into a matrix
                .fuse;

        xyzPixels.writeln;
        xyzPixels.shape.writeln;
}