java设计矩阵类matrix代码

好的，下面是一份简单的 Java 矩阵类 Matrix 的代码：

public class Matrix {
    private final int rows;
    private final int cols;
    private final double[][] data;

    public Matrix(int rows, int cols) {
        if (rows <= 0 || cols <= 0) {
            throw new IllegalArgumentException("rows and cols must be positive");
        }

        this.rows = rows;
        this.cols = cols;
        this.data = new double[rows][cols];
    }

    public int getRows() {
        return rows;
    }

    public int getCols() {
        return cols;
    }

    public double get(int i, int j) {
        checkBounds(i, j);
        return data[i][j];
    }

    public void set(int i, int j, double x) {
        checkBounds(i, j);
        data[i][j] = x;
    }

    private void checkBounds(int i, int j) {
        if (i < 0 || i >= rows) {
            throw new IndexOutOfBoundsException("row index out of bounds");
        }

        if (j < 0 || j >= cols) {
            throw new IndexOutOfBoundsException("col index out of bounds");
        }
    }

    public static Matrix add(Matrix a, Matrix b) {
        if (a.rows != b.rows || a.cols != b.cols) {
            throw new IllegalArgumentException("matrices must have the same dimensions");
        }

        Matrix c = new Matrix(a.rows, a.cols);
        for (int i = 0; i < a.rows; i++) {
            for (int j = 0; j < a.cols; j++) {
                c.data[i][j] = a.data[i][j] + b.data[i][j];
            }
        }

        return c;
    }

    public static Matrix multiply(Matrix a, Matrix b) {
        if (a.cols != b.rows) {
            throw new IllegalArgumentException("number of columns in A must match number of rows in B");
        }

        Matrix c = new Matrix(a.rows, b.cols);
        for (int i = 0; i < a.rows; i++) {
            for (int j = 0; j < b.cols; j++) {
                double sum = 0.0;
                for (int k = 0; k < a.cols; k++) {
                    sum += a.data[i][k] * b.data[k][j];
                }
                c.data[i][j] = sum;
            }
        }

        return c;
    }
}

这个矩阵类支持以下操作：

- 创建矩阵对象：`Matrix m = new Matrix(rows, cols)`
- 获取矩阵的行数和列数：`m.getRows()` 和 `m.getCols()`
- 获取矩阵的某个元素：`m.get(i, j)`
- 设置矩阵的某个元素：`m.set(i, j, x)`
- 矩阵加法：`Matrix.add(a, b)`
- 矩阵乘法：`Matrix.multiply(a, b)`