k nearest neighbor regression function

조회 수: 16 (최근 30일)
Farideh Jalali
Farideh Jalali 2013년 11월 6일
댓글: Satadru Mukherjee 2021년 1월 18일
Hi,
What is the k nearest neighbour regression function in matalb? Is only knn classification function available?
Regards
Farideh

답변 (5개)

wang guangyi
wang guangyi 2015년 11월 17일
i can not find it too

Satadru Mukherjee
Satadru Mukherjee 2020년 3월 10일
편집: Satadru Mukherjee 2020년 3월 10일
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 2020년 3월 10일
Perhaps fitcknn()
  댓글 수: 1
Satadru Mukherjee
Satadru Mukherjee 2021년 1월 18일
fitcknn is for classification , not for regression

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Bechir EL HOSNI
Bechir EL HOSNI 2020년 9월 3일
편집: Bechir EL HOSNI 2020년 9월 3일
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 2020년 9월 23일
Hi
you can use this link to use KNN regression
this paper uses one type of KNN regression to make the QSAR model.
good luck

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