k nearest neighbor regression function

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Farideh Jalali
Farideh Jalali 2013-11-6
评论： Satadru Mukherjee 2021-1-18
Hi,
What is the k nearest neighbour regression function in matalb? Is only knn classification function available?
Regards
Farideh

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回答（5 个）

wang guangyi
wang guangyi 2015-11-17
i can not find it too
Satadru Mukherjee
Satadru Mukherjee 2020-3-10
编辑：Satadru Mukherjee 2020-3-10
clc
clear all
close all
x=input('Enter the x coordinates:');
y=input('Enter the y coordinates:');
z=[];
a=input('Enter the x coordinate of which , you want to predict the y value:');
k=input('Enter the k value:');
for i=1:length(x)
z=[z abs(x(i)-a)];%difference calculation
end
temp=0;
gemp=0;
for i=1:length(z)
for j=1:(length(z)-i)
if(z(j)>z(j+1))
temp=z(j);
z(j)=z(j+1);
z(j+1)=temp;
gemp=y(j);
y(j)=y(j+1);
y(j+1)=gemp;
end
end
end
tuka=0;
for i=1:k
tuka=tuka+y(i);
end
output=tuka/k
Image Analyst
Image Analyst 2020-3-10
Perhaps fitcknn()
Bechir EL HOSNI
Bechir EL HOSNI 2020-9-3
编辑：Bechir EL HOSNI 2020-9-3
Hi
KNN is a non parametric method used in machine learning.
We find two knid of KNN:
KNN classifier: Used in classification problem in which the ouput is a categorical variable.
KNN regression : Used in regression problem in which the output is a numerical variable.
In the context of regression problem we indentifie the first the K (Integer) nearest training points, to the observation we want to predict its output, and next we compute the average of the value of those points. The optimal value of K depend on the "Bias-Vriance tradeoff" ( a very important concept in statistic and machine learning).
Thanks.
Elaheh Shamsi
Elaheh Shamsi 2020-9-23
Hi
you can use this link to use KNN regression
https://www.sciencedirect.com/science/article/abs/pii/S1093326301001231
this paper uses one type of KNN regression to make the QSAR model.
good luck

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