New backend

A much cleaner and faster library. It calls the Accelerate library in most cases (all operators, some simple functions and all complex functions) and is nicely structured (matrix depends on ndarray depends on [Double]).

In addition, I have implemented a complex signal processing algorithm from Matlab to iOS with this framework. The conversion was almost line for line. For example, here's a real-world example of my Matlab-iOS conversion:

swix

var i = abs(S) < mu/2
S[argwhere(i)] = zeros(i.n)
i = argwhere(1 - i) // equivalent to notting every element
S[i] = S[i] - sign(S[i]) * mu/2;
var S0 = zeros((sm, sn))
S0["diag"] = S
var L_new = U *! (S0 *! V)

matlab

i = abs(S) > mu/2;
S(~i) = 0; 
S(i) = S(i) - sign(S(i))*mu/2; 
S = diag(S);
S0(1:min_snm, 1:min_snm) = S;
L_new = U * S0 * V';