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How to calculate threshold for matrix in Matlab?

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phdcomputer Eng
phdcomputer Eng 2019-7-30
编辑： KALYAN ACHARJYA 2019-7-31
I wrote these codes to calculate a threshold for distance values between features of the dataset. after computing hamming distance (a) between columns of the dataset, I defined z value, when the distance between two features is more than z, (for example feature ith and jth) so the threshold is between i and j, and we can select the features based on this threshold and remove the rest of the features. At the end, I used fprintf to show the ith and jth features in the output.
I'll be very grateful to have your opinions how to improve the program to compute the threshold for selecting features. Thanks
close all;
clc
load lung.mat
data=lung;
[n,m]=size(data);
l=1;
t=1;
data1=[];
data2=[];
if data(i,m)==1
data1(l,:)=data(i,:);
l=l+1;
else
data2(t,:)=data(i,:);
t=t+1;
end
end
if t>l
data1(l:t-1,:)=0;
else
data2(t:l-1,:)=0;
end
for i=1: m
thisCol1=data1(:,i);
thisCol2=data2(:,i);
a(i)=fHammingDist(thisCol1,thisCol2);
z=sum(a)/m;
if abs(a(i)-a(j))> z
fprintf(' threshold is between %10.6f and %10.6f ',i,j);
end
end
end
but there is an error for line
if abs(a (i)-a(j)) > z
Subscript indices must either be real positive integers or logicals.

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回答（1 个）

KALYAN ACHARJYA
KALYAN ACHARJYA 2019-7-30
编辑：KALYAN ACHARJYA 2019-7-30
j define?
abs(a(i)-a(j))> z
%..........^
a5?
z=sum(a5)/m;
%.....^
  4 个评论
显示 2更早的评论
phdcomputer Eng
phdcomputer Eng 2019-7-31
I didn't define j in the code, I don't know how to define the counter for passsing an array.
a5 is a typing mistake I meant a.
a(i)=fHammingDist(thisCol1,thisCol2);
a is an array that includes distances between columns of the dataset.
KALYAN ACHARJYA
KALYAN ACHARJYA 2019-7-31
编辑：KALYAN ACHARJYA 2019-7-31
Please do share
>>whos data
and
>>whos a
Also What does it mean "define the counter for passsing an array"?

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