use Random;
use Math;
use Time;
use BlockDist;

config const n = 1000000;

const PI = 3.141592653589793238462643;

proc main() {

	const space = {1..n};
	var Dom: domain(1) dmapped Block(boundingBox=space) = space;

	var p_x: [Dom] real(64);
	var p_y: [Dom] real(64);

	points(p_x, p_y);
	
	
	writeln("Calculate PI with data parallelism");

	var start = getCurrentTime();
	var pi = compute_pi(p_x, p_y);
	var stop = getCurrentTime();

	writeln("PI estimate: ", format("#.#####", pi));
	writeln("PI error: ", format("#.#####", abs(pi - PI)));
	writeln("Time: ", format("#.##", stop - start));
}

proc points(p_x: [] real(64), p_y: [] real(64)) {
	fillRandom(p_x);
	fillRandom(p_y);
	return;
}

proc in_circle(x: real(64), y: real(64)): bool
{
	return (x ** 2 + y ** 2) <= 1;
}

proc compute_pi(p_x: [] real(64), p_y: [] real(64)) : real {
	var c = +reduce in_circle(p_x, p_y);
	return c * 4.0 / n;
}