parfeval feature

[Nelson-numerical-software]

using C++ 17 features as future, thread pool

tic()
A = rand(3000, 3000);
B = rand(3000,3000);
C = rand(3000,3000);
D = rand(3000,3000);
toc();

tic()
b = backgroundPool();
h = str2func('rand');

f1 = parfeval(b, h, 1, 3000, 3000);
f2 = parfeval(b, h, 1, 3000, 3000);
f3 = parfeval(b, h, 1, 3000, 3000);
f4 = parfeval(b, h, 1, 3000, 3000);

A = fetchOutputs(f1);
B = fetchOutputs(f2);
C = fetchOutputs(f3);
D = fetchOutputs(f4);

toc()

see https://github.com/Nelson-numerical-software/nelson/tree/parallel