initialize_beliefs_improved.cpp

#include "headers/initialize_beliefs_improved.h"

using namespace std;

// Not necessary to pass in the grid variable since it is never used
// Could either pass by reference or just pass in the height and width
vector< vector <float> > initialize_beliefs_improved(int height, int width) {

	// not necessary to calculate the area variable first since it is only used once
	float prob_per_cell = 1.0 / float(height * width);

	vector<float> row;
	vector< vector<float> > newGrid;

	// because the vectors are not of variable length, 
	// it is faster to reserve space in memory for the vectors
	row.reserve(width);
	newGrid.reserve(height);

	// avoiding nested for loops since in this case it is not needed
	// each element in the 2D vector has the exact same value
	for (int i = 0; i < width; i++) {
		row.push_back(prob_per_cell);
	}

	for (int i = 0; i < height; i++) {
		newGrid.push_back(row);
	}

	return newGrid;
}