#include <iostream>
#include <vector>
#include <ctime>
#include <cmath>
#include <fstream>
#include "mersenne.h"

using namespace std;

#define ARRAYELEMCOUNT(x) sizeof(x) / sizeof(x[0])

#define TAB "\t"

//Rand01IE: Get random number from [0,1)
#define Rand01IE() mersenne()
#define SeedRand(x) seed_mersenne(x)

//This sets random values[0,1) to every coordinate of a double array.
inline void RandomiseValues(double* const array, const int size)
//----------------------------------------------------------
{
	for(int i = 0; i<size; i++) array[i] = Rand01IE();
	//Note: When taking random vectors from [-1,1] hypercube, coordinate can be negative,
	//but here taking only values from [0,1). This is(?) ok in this particular task
	//since negative coordinate gives exactly the same contribution to the vector length
	//as positive.
}

inline double LengthSquared(double* const array, const int size)
//----------------------------------------------------------------------
{
	double sum = 0;
	for(int i = 0; i<size; i++) sum += array[i]*array[i];
	return sum;
}


int main()
//--------
{
	const int seed = time(0);
	SeedRand(seed);
	const int samples[] = {10000, /*10000000*/};
	const int dims[] = {1,2,3,4,5,6,7,8,9,10,12,14,16,18};

	ofstream fout("hw3.txt", ios::trunc);
	ostream& oStrm = fout;
	oStrm.width(20);

	oStrm << "#seed: " << seed << endl;
	oStrm << "#columns: dim\tsphereVol\tboxvol\thits\tmisses" << endl;
	for(int j = 0; j<ARRAYELEMCOUNT(samples); j++)
	{
		cout << "j = " << j << endl;
		oStrm << "#samples: " << samples[j] << endl;
		for(int i = 0; i<ARRAYELEMCOUNT(dims); i++)
		{
			int hits = 0, misses = 0;
			vector<double> x(dims[i], 0);
			for(int n = 0; n<samples[j]; n++)
			{
				RandomiseValues(&x[0], x.size());
				if(LengthSquared(&x[0], x.size()) <= 1) hits++;
				else misses++;
			}

			const double boxvol = pow(2.0, double(dims[i]));

			oStrm << dims[i] << TAB
				  << boxvol * double(hits)/(hits+misses) << TAB
				  << boxvol << TAB
				  << hits << TAB << misses << endl;	
		}
		oStrm << endl;
	}

	return 0;
}