/* Matrix
 * <Description>
 * Takes the dot product of 2 1D arrays or multiplies 2 2D arrays.
 * 
 * <Usage>
 * javac Matrix.java
 * ----------Just Tests---------
 * java Matrix
 * ----------End Tests----------
 *
 * ---------1D Arrays(Dot)--------
 * ######################
 * #####example.txt######
 * ######################
 * #4                   #
 * #1 2 3 4             #
 * #4                   #
 * #5 6 7 8             #
 * ######################
 * java Matrix 1 < example.txt
 * --------END 1D Arrays(Dot)-----
 * 
 * ---------2D Arrays(Multiply)-------
 * ######################
 * #####example.txt######
 * ######################
 * #3 3                 #
 * #9 8 7               #
 * #6 5 4               #
 * #3 2 1               #
 * #3 3                 #
 * #1 2 3               #
 * #4 5 6               #
 * #7 8 9               #
 * ######################
 * java Matrix 2 < example.txt
 * -------END 2D Arrays(Multiply------
 * 
 * <References>
 * CIS201-L UAB SUMMER 2014 Dr. Sloan
 * @author
 * Dan Latham <l3li3l@torguard.tg>
 *
 * @version 0.0.1
 *
 */
 

public class Matrix
{
	public static double dot(double[] a, double[] b)
	{
		//dot = a ** b = a1*b1 + a2*b2 + a3*b3...
		//System.out.println("dot_Test");
		//check
		assert (a.length == b.length);
		//counter
		double c = 0;
		
		for (int i = 0; i <= a.length-1; i+=1)
		{
			double d = a[i]*b[i];
			c += d;
		}
		return c;
	}
		
	public static double[][] multiply(double[][] firstarray, double[][] secondarray)
	{
		/* Create another 2d array to store the result
		 * using the original arrays' lengths on row and column respectively. */
		double [][] result = new double[firstarray.length][secondarray[0].length];

		/* Loop through each and get product, then sum up and store
		 * the value */
		for (int i = 0; i < firstarray.length; i++)
		{ 
			for (int j = 0; j < secondarray[0].length; j++)
			{ 
				for (int k = 0; k < firstarray[0].length; k++)
				{ 
					result[i][j] += firstarray[i][k] * secondarray[k][j];
				}
			}
		}
		return result;
	}
	public static void test()
	{
		System.out.println("--------------------TESTS------------------");
		//DOT tests
		double[] a0 = {1,2,3,4,5};
		double[] b0 = {6,7,8,9,10};
		System.out.println("DOT test #0: " + dot(a0,b0));
		double[] a1 = {8,3,5,2,4,6,7};
		double[] b1 = {1.2,33.5,5,8,9,1,2};
		System.out.println("DOT test #1: " + dot(a1,b1));
		//Multiply tests
		double[][] a2 = {
			{1,2,3},
			{4,5,6},
			{7,8,9}
			};
		double[][] b2 = {
			{9,8,7},
			{6,5,4},
			{3,2,1}
			};
		double zzz[][] = multiply(a2,b2);
		StdArrayIO.print(zzz);
		
		double[][] a3 = {
			{1,2,3},
			{4,5,6}
			};
		double[][] b3 = {
			{7,8},
			{9,10},
			{11,12}
			};
		double zzz1[][] = multiply(a3,b3);
		StdArrayIO.print(zzz1);
		System.out.println("------------------END TESTS----------------");
	}
	
	public static void main(String[] args)
	{
		if (args.length == 0)
		{
			test();
			System.exit(1);
		}
		int c = Integer.parseInt(args[0]);
		if (c == 1)
		{
			double[] a = StdArrayIO.readDouble1D();
			double[] b = StdArrayIO.readDouble1D();
			System.out.println("Dot is: "+dot(a,b));
		}
		else if (c == 2)
		{
			double[][] a = StdArrayIO.readDouble2D();
			double[][] b = StdArrayIO.readDouble2D();
			StdArrayIO.print(multiply(a,b));
		}
		else System.out.println("Options are 1 for 1D arrays(dot) and 2 for 2D arrays(multiply)");
	}
}