Matlab 多维版本的；克朗“；产品？

现在我有一个矩阵a的维数是N乘以p，另一个矩阵B的维数是N乘以q。我想要的是一个矩阵，比如说C，维数N乘以pq，这样

C(i,:) = kron(A(i,:), B(i,:));

如果N较大，则在N行上循环可能需要相当长的时间。因此，目前我正在适当地增加A和B（结合使用repmat、permute和reforme），以将维度N的每个矩阵转化为pq，然后用类似的公式表示C

C = A_aug .* B_aug;

有更好的主意吗？

检查一下++魔术-

---

基准测试与验证

基准测试代码-

%// Setup inputs
N = 200;
p = 190;
q = 180;
A = rand(N,p);
B = rand(N,q);

disp('--------------------------------------- Without magic')
tic
C = zeros(size(A,1),size(A,2)*size(B,2));
for i = 1:size(A,1)
    C(i,:) = kron(A(i,:), B(i,:));
end
toc

disp('--------------------------------------- With some magic')
tic
out = reshape(bsxfun(@times,permute(A,[1 3 2]),B),size(A,1),[]);
toc

error_val = max(abs(C(:)-out(:)))

输出-

--------------------------------------- Without magic
Elapsed time is 0.524396 seconds.
--------------------------------------- With some magic
Elapsed time is 0.055082 seconds.
error_val =
     0

---

查看MATLAB的FileExchange上的

superkron

-

--------------------------------------- Without magic
Elapsed time is 0.524396 seconds.
--------------------------------------- With some magic
Elapsed time is 0.055082 seconds.
error_val =
     0