package test;

import Jama.Matrix;

public class LectureExample {
	public static void main(String[] args) {
		// This example application solves the matrix equation A*betas=b, where:
		//     [   7    90   1571]
		// A = [  90  1746  26905]
		//     [1571 26905 440239]
		//
		// b = {2438 36506 625765}
		//
		
		// create a 3x3 matrix "A" with all elements initialized to 0
		Matrix A = new Matrix(3,3,0.0); 
		
		// set the actual values for the first row (be careful - Matrix elements are 0-based!!!):
		A.set(0,0, 7);		// set row 0, col 0 to 7
		A.set(0,1, 90);		// set row 0, col 1 to 90
		A.set(0,2, 1571);	// set row 0, col 2 to 1571
		
		// second row:
		A.set(1,0, 90);
		A.set(1,1, 1746);
		A.set(1,2, 26905);

		// third row:
		A.set(2,0, 1571);
		A.set(2,1, 26905);
		A.set(2,2, 440239);
		
		// create a 3x1 matrix (a column vector) "b" with all elements initialized to 0:
		Matrix b = new Matrix(3,1,0.0);
		// now set the values:
	    b.set(0,0, 2438);
	    b.set(1,0, 36506);
	    b.set(2,0, 625765);
	    
	    // print out the A matrix for debugging purposes
	    System.out.println("A values");
	    for( int i=0; i<A.getRowDimension(); i++ ) {
	    	for( int j=0; j<A.getColumnDimension(); j++ ) {
	    		System.out.print( A.get(i, j) + "\t");
	    	}
	    	System.out.println("");
	    }

	    // now solve for betas in A*betas=b, letting the JAMA Matrix.solve() method do all work...
	    Matrix betas = A.solve(b); 
	    
	    // print out the result; should agree with expected answer
	    System.out.println("\nbeta values");
	    System.out.println(betas.get(0,0));
	    System.out.println(betas.get(1,0));
	    System.out.println(betas.get(2,0));
	    
//	    System.out.println("\nbetas row dimension: " + betas.getRowDimension() );
//	    System.out.println("betas column dimension: " + betas.getColumnDimension() );
	}
}