3x3矩阵，1x1矩阵，3X3零矩阵融合，矩阵乘法

1. 理论

$$\begin{array}{c}\left[\begin{array}{ccc}4& 2& 9\\ & & \\ 2& 4& 3\\ & & \\ 6& 9& 2\end{array}\right]+9+0\to \left[\begin{array}{ccc}4& 2& 9\\ & & \\ 2& 4& 3\\ & & \\ 6& 9& 2\end{array}\right]+\left[\begin{array}{ccc}0& 0& 0\\ & & \\ 0& 9& 0\\ & & \\ 0& 0& 0\end{array}\right]+\left[\begin{array}{ccc}0& 0& 0\\ & & \\ 0& 0& 0\\ & & \\ 0& 0& 0\end{array}\right]=\left[\begin{array}{ccc}4& 2& 9\\ & & \\ 2& 13& 3\\ & & \\ 6& 9& 2\end{array}\right]\end{array}$$

2. python 代码

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# @FileName  :padding3x3.py
# @Time      :2024/12/1 14:00
# @Author    :Jason Zhang
import torch
from torch import nn

torch.set_printoptions(sci_mode=False, precision=3)
torch.manual_seed(455)
if __name__ == "__main__":
    run_code = 0
    matrix_3 = torch.randint(1, 10, (3, 3), dtype=torch.float)
    matrix_1 = torch.randint(1, 10, (1, 1), dtype=torch.float)
    ones_left = torch.zeros((3, 1))
    ones_left[1] = 1
    print(f"ones_left=\n{ones_left}")
    matrix_13 = ones_left @ matrix_1 @ ones_left.T
    matrix_03 = torch.zeros_like(matrix_3)
    result = matrix_03 + matrix_13 + matrix_3
    print(f"matrix_1=\n{matrix_1}")
    print(f"matrix_13=\n{matrix_13}")
    print(f"matrix_3=\n{matrix_3}")
    print(f"matrix_03=\n{matrix_03}")
    print(f"result=\n{result}")

ones_left=
tensor([[0.],
        [1.],
        [0.]])
matrix_1=
tensor([[9.]])
matrix_13=
tensor([[0., 0., 0.],
        [0., 9., 0.],
        [0., 0., 0.]])
matrix_3=
tensor([[4., 2., 9.],
        [2., 4., 3.],
        [6., 9., 2.]])
matrix_03=
tensor([[0., 0., 0.],
        [0., 0., 0.],
        [0., 0., 0.]])
result=
tensor([[ 4.,  2.,  9.],
        [ 2., 13.,  3.],
        [ 6.,  9.,  2.]])