How to create the "for" loop?

조회 수: 8 (최근 30일)
Rahul Verma
Rahul Verma 2023년 4월 10일
댓글: Dyuman Joshi 2023년 4월 10일
I am trying to create 'for' loop for one easy problem. It is a simple subsraction.
Let me explain more about. So i want to calculate "v" by using this formula; v = datainput - XSS
Here, the size of datainput is 34*36 and size of XSS is 34*1296.
Now, the trick is that when the substraction takes place, it should be in a manner that 1st column of datainput - /minus whole XSS, (which will give a matrix of size 34*1296). Likewise for whole 36 columns the substraction should happen. And the final result should be stored in v (of size 34*36*1296).
For this i am attaching the datainput and XSS excel files.

답변 (1개)

Dyuman Joshi
Dyuman Joshi 2023년 4월 10일
편집: Dyuman Joshi 2023년 4월 10일
Loop approach
datainput=rand(34,36);
XSS=rand(34,1296);
%Preallocation
v=zeros(34,36,1296);
for k=1:size(datainput,2)
v(:,k,:)=datainput(:,k)-XSS;
end
Vectorized approach -
V=datainput-permute(XSS,[1 3 2]);
%Ideally one should you tolerance to compare floating point numbers
isequal(v,V)
ans = logical
1
  댓글 수: 2
Rahul Verma
Rahul Verma 2023년 4월 10일
In both appraoches, its showinng error. Size of matrix is not matching.
Dyuman Joshi
Dyuman Joshi 2023년 4월 10일
It's working fine here. How are you importing your data?
XSS=readmatrix('XSS.xlsx');
size(XSS)
ans = 1×2
34 1296
datainput=readmatrix('datainput.xlsx');
size(datainput)
ans = 1×2
34 36
v=zeros(34,36,1296);
for k=1:size(datainput,2)
v(:,k,:)=datainput(:,k)-XSS;
end
V=datainput-permute(XSS,[1 3 2]);
isequal(v,V)
ans = logical
1

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