> MATLAB is slow and Octave is even slower while working with matrices.

I'm curious what you mean with this. Matlab was always fast with matrices (but my experience is now from 2 decades ago). The thing that was slow was loops. That is:

  for i = 1:100
    c(i) = a(i) + b(i);
  end

would always be slower than this:

  c = a .+ b;

The trick in my work was to always find matrix/vector operations that were equivalent to my desired loop and conditional structures. I could improve execution by 100x or more for many programs doing this.