private double getReferenceTime(int n) {
final long t0 = System.nanoTime();
for (int i = 0; i < n * 100; i++) { // Jacobi is less than 100 times slower
Math.acos(1.0e-5 * Math.random());
}
final long t1 = System.nanoTime();
return (t1 - t0) / 1.0e9;
}
