如果你正在尋找一個解決方案矢量,你可以這樣做:
nTags = max(L(:));
whois = bsxfun(@eq,L,reshape(1:nTags,1,1,[]));
% whois = L == reshape(1:nTags,1,1,[]); % >=R2016b syntax.
[X,Y,Z] = ind2sub(size(whois), find(whois));
tmp = find(diff([0; Z; nTags+1])); tmp = reshape([tmp(1:end-1) tmp(2:end)-1].',[],1);
M = [X(tmp), Y(tmp), repelem(1:nTags,2).'];
或者極端變量重用:
nTags = max(L(:));
Z = bsxfun(@eq,L,reshape(1:nTags,1,1,[]));
[X,Y,Z] = ind2sub(size(Z), find(Z));
Z = find(diff([0; Z; nTags+1]));
Z = reshape([Z(1:end-1) Z(2:end)-1].',[],1);
M = [X(Z), Y(Z), repelem(1:nTags,2).'];
這裏是我的基準測試代碼:
function varargout = b42973322(isGPU,nLabels,lMat)
if nargin < 3
lMat = 1000;
end
if nargin < 2
nLabels = 20; % if nLabels > intmax('uint8'), Change the type of L to some other uint.
end
if nargin < 1
isGPU = false;
end
%% Create L:
if isGPU
L = sort(gpuArray.randi(nLabels,lMat,lMat,'uint8'),2);
else
L = sort(randi(nLabels,lMat,lMat,'uint8'),2);
end
%% Equality test:
M{3} = DeviL2(L);
M{2} = DeviL1(L);
M{1} = Adiel(L);
assert(isequal(M{1},M{2},M{3}));
%% Timing:
% t(3) = timeit(@()DeviL2(L)); % This is always slower, so it's irrelevant.
t(2) = timeit(@()DeviL1(L));
t(1) = timeit(@()Adiel(L));
%% Output/Print
if nargout == 0
disp(t);
else
varargout{1} = t;
end
end
function M = Adiel(L)
M=[];
for k=1:max(L(:))
[r,c]=find(L==k);
s=sortrows([r c],2);
M=[M;s(1,:) k; s(end,:) k];
end
end
function M = DeviL1(L)
nTags = max(L(:));
whois = L == reshape(1:nTags,1,1,[]); % >=R2016b syntax.
[X,Y,Z] = ind2sub(size(whois), find(whois));
tmp = find(diff([0; Z; nTags+1])); tmp = reshape([tmp(1:end-1) tmp(2:end)-1].',[],1);
M = [X(tmp), Y(tmp), repelem(1:nTags,2).'];
end
function M = DeviL2(L)
nTags = max(L(:));
Z = L == reshape(1:nTags,1,1,[]);
[X,Y,Z] = ind2sub(size(Z), find(Z));
Z = find(diff([0; Z; nTags+1]));
Z = reshape([Z(1:end-1) Z(2:end)-1].',[],1);
M = [X(Z), Y(Z), repelem(1:nTags,2).'];
end
「M」的第一行不應該是「1 1 1」嗎? –
是的你對!,我編輯 –
另外,您正在使用哪個版本的MATLAB? –