Question

我遇到了跨产品功能的问题。我需要为每个像素取两个向量的叉积，然后求和所有像素的结果。

 i=1;     
 [h,w,d] = size(current_vec);
 for pxRow = 1:h % fixed pixel row
 for pxCol = 1:w % fixed pixel column
 for pxsize = 1:d 

 for r = 1:h % row of distant pixel
 for c = 1:w % column of distant pixel
 for dpth = 1:d

 bfield(c,r,dpth) = cross(current_vec(c,r,dpth),dist_vec(c,r,dpth));                               % pythagoras theorem to get distance to each pixel                                                                     % unit vector from x to s                     

 end
 end
 end
 Bfield(i) = {bfield}; % filling a cell array with results. read below
 i = i+1;
 end
 end
 end


??? Error using ==> cross at 37
A and B must have at least one dimension of length 3.

??? Error using ==> cross at 37
A and B must have at least one dimension of length 3.

Error in ==> MAC2 at 71
bfield(c,r,dpth) = cross(current_vec(c,r,dpth),dist_vec(c,r,dpth));

但是有问题的向量current_vec和dist_vec如下：

>> size(current_vec)

ans =

    35    35     3

>> size(dist_vec)

ans =

    35    35     3

因此，就我而言，他们填写了在交叉产品中使用的标准。为什么不是这种情况？

Answer 1

您需要使用cross的矢量化形式：

bfield = cross(current_vec,dist_vec);

cross将在长度为3的第一个维度上工作。使用嵌套循环执行此操作的方式，您通过索引访问单个元素（标量）。你不能用标量穿过标量。

matlab - 跨产品错误

1 个答案: