Performance 快速比较矩阵行的方法？

我有一个代码，在运行过程中重复几次。此代码将

C

的行逐行进行比较。它需要很长时间才能运行，特别是对于大型

C

。我正在寻找一种快速的方法来运行它。我使用了

a（ismember（a，b））

而不是

intersect（a，b）

这将是一种方法-

%// Get the size of C and pairwise indices
N = size(C,1);
[Y,X] = find(bsxfun(@gt,[1:N]',[1:N])); %//'

%// Form the two pairs
p1 = C(X,:);
p2 = C(Y,:);

%// Get the matches for each element in a row against all other elements in
%// the matching row pair combinations. This would be equivalent to
%// ISMEMBER implementation in the original code
matches = squeeze(any(bsxfun(@eq,permute(p1,[3 2 1]),permute(p2,[2 3 1])),1));
matches = reshape(matches,[],numel(Y)); %//for special case when C has 2 rows

%// Get linear indices that satisfy the equality criteria from original code
idx = find(sum(matches.'.*p1,2) == sum(p2,2)); %//'

%// Store the row and column information from the linear indices
K_vectorized = Y(idx);
K1_vectorized = X(idx);

---

C

的典型数据大小是什么？谢谢您的提示。

C

的行数最多可达1500行。它有更少的列（最多5列）。你想用它做什么？@knedlsepp:我想找到多余的行。冗余行是指具有其他行元素子集和零的行。例如，如果

C=[17 18 5；3 5 7；17 18 0；4 17 2；5 0 0]

，那么

C（3，：）

和

C（5，：）

是多余的。因此，

n=2

，

K=[35]

和

K1n=[12]

@Meher81:您的原始代码与您在注释中描述的不完全一样。只有当

C

的条目不是负数时，此项才有效。您的代码对某些C无效。我找不到原因。例如，请测试它的

C=[3,4,0,0；4,8,0,0；]

@Divakar:

C

包含零和正整数。@Meher81必须添加一行来处理该特殊情况。现在就去看看。

%// Get the size of C and pairwise indices
N = size(C,1);
[Y,X] = find(bsxfun(@gt,[1:N]',[1:N])); %//'

%// Form the two pairs
p1 = C(X,:);
p2 = C(Y,:);

%// Get the matches for each element in a row against all other elements in
%// the matching row pair combinations. This would be equivalent to
%// ISMEMBER implementation in the original code
matches = squeeze(any(bsxfun(@eq,permute(p1,[3 2 1]),permute(p2,[2 3 1])),1));
matches = reshape(matches,[],numel(Y)); %//for special case when C has 2 rows

%// Get linear indices that satisfy the equality criteria from original code
idx = find(sum(matches.'.*p1,2) == sum(p2,2)); %//'

%// Store the row and column information from the linear indices
K_vectorized = Y(idx);
K1_vectorized = X(idx);