实现自定义算子：逆矩阵inverse

import torch
from torch.linalg import det
 
def cof1(M,index):
    zs = M[:index[0]-1,:index[1]-1]
    ys = M[:index[0]-1,index[1]:]
    zx = M[index[0]:,:index[1]-1]
    yx = M[index[0]:,index[1]:]
    s = torch.cat((zs,ys),axis=1)
    x = torch.cat((zx,yx),axis=1)
    return det(torch.cat((s,x),axis=0))
 
def alcof(M,index):
    return pow(-1,index[0]+index[1])*cof1(M,index)
 
def adj(M):
    result = torch.zeros((M.shape[0],M.shape[1]))
    for i in range(1,M.shape[0]+1):
        for j in range(1,M.shape[1]+1):
            result[j-1][i-1] = alcof(M,[i,j])
    return result
 
def invmat(M):
    return 1.0/det(M)*adj(M)
 
M = torch.FloatTensor([[1,2,-1],[2,3,4],[3,1,2]])
print(invmat(M))
print(torch.inverse(M))