package edu.msud.cs.cs1.IPJ5;
public class Matrix {

    public static double dot (double[]x, double[]y)
    {
        int n = x.length;
        double sum = 0;
        if(x.length != y.length) {
            System.out.println("undefined dimensions");
        }
        else {
            for (int i = 0; i < n; i++)
            {
                sum += x[i] * y[i];
            }
        }
        return sum;
    }
    public static double[][] multiply(double[][]x, double[][]y) { //matrix-matrix
        double[][] c = new double[x.length][y[0].length];
        /* ^^create new array two hold both arrays, of size R: array 1 rows, C: array 2 columns*/

        if (y.length == x[0].length) {
            for (int i = 0; i < x.length; i++) {
                for (int j = 0; j < y[0].length; j++) {

                    for (int k = 0; k < x[0].length; k++) {
                        c[i][j] += x[i][k] * y[k][j];

                    }

                }
            }
        }
        else
        {
            System.out.println("Dimension requirements not satisfied for accurate calculation");
        }
        return c;
    }
    public static double[] multiply(double[]x, double[][]y) { //vector-matrix
        double[] c = new double[y[0].length];
//        System.out.println(y[0].length);
        /* ^^create new array two hold both arrays, of size R: array 1 rows, C: array 2 columns*/

//            c[0] = x[0] * y[0][0];
            for (int i = 0; i < x.length; i++) {
                for (int j = 0; j < y[0].length; j++) {

                        c[i] += x[i] * y[i][j];

                }
            }

        return c;
    }
    public static double[] multiply(double[][]x, double[]y) { //matrix-vector
        double[] c = new double[x[0].length];


        for (int i = 0; i < x[0].length; i++) {
            for (int j = 0; j < y.length; j++) {

                c[i] +=x[i][j] * y[j];

            }
        }

        return c;
    }
    public static void printArray (double[][]v) //static method to print results of other methods
    {
        for(int i = 0; i < v.length; i++)
        {
            for(int j = 0; j < v.length; j++)
            {
                System.out.print(v[i][j] + " ");
            }
            System.out.println();
        }
    }
    public static void printArray (double[]v) //static method to print results of other methods
    {
        for(int i = 0; i < v.length; i++)
        {
            System.out.print(v[i] + " ");
        }
    }

    public static void main (String[] args)
    {
//        double[] a = { 1,2,3,4 };
//        double[] b = { 1,2,3,4 };
//        System.out.println(dot(a,b));
        double[][]a = {
                {1,2,3,4},
                {5,6,7,8},
                {9,10,11,12},
                //print array a
        };
        for(int i = 0; i < a[0].length-1; i++)
        {
            for(int j = 0; j < a[0].length; j++)
            {
                System.out.print(a[i][j] + " ");
            }
            System.out.println();
        }


        double[]b = {
                -1,-2,-3

        };
        System.out.println();
        //print array b
        for(int i = 0; i < b.length; i++)
        {

                System.out.print(b[i] + " ");
        }
        System.out.println();
        printArray(multiply(b,a));

    }
}