pdist2 function

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A
A 2012-2-7
评论： Ana Gonçalves 2022-2-16
I'm trying to use the pdist2 function and keep getting this error: "??? Undefined function or method 'pdist2' for input arguments of type 'double'" The 'double' part changes depending on what data type I use, so that part can be ignored.
The statistics toolbox is in my path and I can do "help pdist2" and have the help file come up.
I have tried the examples within the help file and this still doesn't work.
The only thing I can think of is there is a function within pdist2 called partialSort, but no matter how much searching I do, I see no matlab function for this???
Anyone know why my pdist2 doesn't work?
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Sean de Wolski
Sean de Wolski 2012-2-8
I would guess it's not installed correctly. Is it on your path?
>>path
Ana Gonçalves
Ana Gonçalves 2022-2-16
As alternative, you can use this function I developed to replace pdist2.
You can thank me later ;)
function Distance = euclidean(x,y)
% This function replaces the function pdist2 available only at the Machine
% Learning toolbox. It computes the distances between rows of X.
% Autor: Ana C. Goncalves
% n = norm(v) returns the Euclidean norm of vector v. This norm is also
% called the 2-norm, vector magnitude, or Euclidean length.
for i = 1:length(x)
for j = 1:length(y)
if i ~= j
%Distance(i,j) = sqrt((x(i)-x(j))^2 + (y(i)-y(j))^2); % Don't literally work because calculates the distance btw thw columns.
Distance(i,j) = norm(x(i,:) - x(j,:));
end
end
end
end

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回答（3 个）

Benjamin Schwabe
Benjamin Schwabe 2012-2-7
Okay, my MATLAB does not know a pdist2 function, only pdist. (I am using MatLabd r2009b)
Could it be that simple?
Otherwise, in which folder is the pdist2.m file? Add this to the path or change working directory accordingly.
  1 个评论
A
A 2012-2-8
i'm using r2010b and pdist2 was added to this version

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Chathurika
Chathurika 2013-2-20
if you don't have a working pdist2, use the following code..it could be little slower than pdist2..but works fine..
pairwise distance between rows of matrix A and B....A and B should have same no of columns....output D is a 2D matrix with ij entry giving distance between ith row of A and jth row of B....distance used is L1 norm..
tmpB(1,:,:)=B';
x=repmat(tmpB,[size(A,1),1,1]);
y=repmat(A,[1,1,size(x,3)]);
D(:,:)=sum(abs(x-y),2);
ROCKTIM JYOTI DAS
ROCKTIM JYOTI DAS 2019-10-28
how to compare two histogram of images
  1 个评论
Steven Lord
Steven Lord 2019-10-28
This isn't related to the original question. Please ask it as its own question. When you ask it as its own question, you should provide more details about how you want to compare the histograms (just answer "Are they the same?", answer "How many bins are different?", answer "How much does each bin differ between the two images?", etc.)

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