Finding the matrix entrywise sum using element-wise addition.

Here’s a Java code example that finds the matrix entrywise sum using element-wise addition:

public class MatrixEntrywiseSum {

    public static void main(String[] args) {

        int[][] matrix1 = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };

        int[][] matrix2 = { { 9, 8, 7 }, { 6, 5, 4 }, { 3, 2, 1 } };

        int[][] sumMatrix = getEntrywiseSum(matrix1, matrix2);

        // Print the sumMatrix

        for (int i = 0; i < sumMatrix.length; i++) {

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

                System.out.print(sumMatrix[i][j] + " ");

            }

            System.out.println();

        }

    }

    public static int[][] getEntrywiseSum(int[][] matrix1, int[][] matrix2) {

        int rows = matrix1.length;

        int columns = matrix1[0].length;

        int[][] sumMatrix = new int[rows][columns];

        for (int i = 0; i < rows; i++) {

            for (int j = 0; j < columns; j++) {

                sumMatrix[i][j] = matrix1[i][j] + matrix2[i][j];

            }

        }

        return sumMatrix;

    }

}

In this code, we have two matrices, `matrix1` and `matrix2`. The `getEntrywiseSum` method takes these two matrices as input and calculates the entrywise sum by adding the corresponding elements from each matrix. The resulting sum matrix is then returned.

The `main` method demonstrates the usage by creating two example matrices, calling the `getEntrywiseSum` method, and printing the resulting sum matrix. In this case, the output would be:

10 10 10

10 10 10

10 10 10

Each element of the sum matrix is obtained by adding the corresponding elements from `matrix1` and `matrix2`.