/**
 * 
 */
package util;

/**
 * Performs Matrix Operations.
 * @author John H. Krantz, Ph.D.
 *
 */
public class Matrix {
	
	/**
	 * Does a standard matrix muliplication operation.
	 * Assumes that at the number of columns of m1 = number
	 * of rows of m2
	 * @param double [][] m1
	 * @param double [][] m2
	 * @return 
	 */
	public double [][] mMult(double [][] m1, double [][] m2){
		double [][] temp = null;
		
		// test that matrices fit requirements
		if (m1[0].length == m2.length){
			temp =  new double [m1.length][m2[0].length];
			for (int i = 0; i < temp.length; i ++){
				for (int j = 0; j < temp[0].length; j ++){
					temp[i][j] = 0;
					for (int r = 0; r < m1[0].length; r ++){
						temp[i][j] += m1[i][r]*m2[r][j];
					}// end for r
				}// end for j
			} // end for i
		} // end doing matrix mult
		
		return temp;
	}
	/**
	 * Does a standard matrix muliplication operation.
	 * Assumes that at the number of columns of m1 = number
	 * of elements of m2 and m2 is a one dimensional array.
	 * @param double [][] m1
	 * @param double [] m2
	 * @return 
	 */
	public double [] mMult(double [][] m1, double [] m2){
		// convert one dimensional array to a 2d array
		// and use over version of this method
		double [][] temp = new double [m2.length][1];
		for (int i = 0; i < m2.length; i ++){
			temp[i][0] = m2[i];
		}
		// do the matrix multiplication
		double [][] tt = mMult(m1,temp);
		// convert output to 1d array
		double t [] = new double[m2.length];
		for (int i = 0; i < m2.length; i ++){
			t[i] = tt[i][0];
		}
		return t;
	}

}