Compare a = pinv(A)*b and a = A\b, with timing in GNU Octave

solveTest.m

function [ti ts delta] = solveTest(n)
% Compares a = pinv(A)*b and a = A\b, with timing.

%#####################################################%
$ Thanks to John D. Cook of 
$ http://www.johndcook.com/blog/2010/01/19/dont-invert-that-matrix/
$ where he mentioned that solving vs inverting is O(n^2) vs O(n^3)
$
% Results:
% solveTest(1000); => 
% 13.55s for inversion, 0.16s for A\b. Difference 0.00
%
% solveTest(1500);
% 43.69s for inversion, 0.52s for A\b. Difference 0.00
%
% solveTest(2000);
% 108.68s for inversion, 1.15s for A\b. Difference 0.00
%
% on GNU Octave, version 3.2.4 (32bit), Win 7 (64 bit)
%
% Greetings to the @ml_class team!
%#####################################################%

%initialize
A = rand(n);
b = rand(n,1);

t0 = time; 

% solve with inverse
Ai = pinv(A); 
a_i = Ai * b;

t1 = time; 
ti = t1-t0;

% solve with A \ b
a_s = A \ b;

t2 = time;
ts = t2 - t1;

% compare
delta = sum(abs(a_i - a_s));

fprintf("%0.2fs for inversion, %0.2fs for A\\b. Difference %0.2f \n",ti,ts,delta);
[ti ts delta];