How do I get the combination of cell array "wmn" and set up the preallocation of "wmn"

Question

Mark 2021-6-8

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/850400-how-do-i-get-the-combination-of-cell-array-wmn-and-set-up-the-preallocation-of-wmn

评论： Mark 2021-6-8

Below is my code.

In the last line of my code. Because "i" is variable, I would like to ask how to combine the wmn without using "Combine=wmn{1}+wmn{2}+wmn{3}+wmn{4}". So I can combine more term when "i" is a large number.

Also, about the second for loop, I would like to know how should I preallocate the "wmn array" with zero matrix, just as I did for the first for loop "amn=zeros(1,len)" so that I can do the calculation more efficiently.

Thank you very much!!

clc
clear
format long
E=209e+3; 
q=-1; 
h=15; 
D=6.459478021978022e+07; 
I=2.8125e+02; 
a=600;b=2400; 
% change the value of mn
n =7;
[T1, T2] = meshgrid(1:2:n);
mn = [T1(:), T2(:)]
syms x y
x_value=0:10:600;
y_value=0:10:2400;
[X,Y]=meshgrid(x_value,y_value)
% Fine the amn
len=length(mn);
amn=zeros(1,len);
for  i=1:len
    m=mn(i,1);
    n=mn(i,2);
    amn(i)=(16*q/(m*n*D*pi^6))*(1/((m/a)^2+(n/b)^2)^2); % amn(i) storage the array
end
% Fine the wmn
% How do I preallocate the wmn array?
for i=1:len
    m=mn(i,1);
    n=mn(i,2);
    wmn{i}=amn(i).*((sin(m.*pi.*X./a)).*(sin(n.*pi.*Y./b))); 
end
% How do I find the combination of wmn ?
 Combine=wmn{1}+wmn{2}+wmn{3}+wmn{4}

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Answer 1

KSSV 2021-6-8

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/850400-how-do-i-get-the-combination-of-cell-array-wmn-and-set-up-the-preallocation-of-wmn#answer_719390

编辑：KSSV 2021-6-8

在 MATLAB Online 中打开

clc; clear all ;
clc
clear
format long
E=209e+3; 
q=-1; 
h=15; 
D=6.459478021978022e+07; 
I=2.8125e+02; 
a=600;b=2400; 
% change the value of mn
n =7;
[T1, T2] = meshgrid(1:2:n);
mn = [T1(:), T2(:)]
syms x y
x_value=0:10:600;
y_value=0:10:2400;
[X,Y]=meshgrid(x_value,y_value) ; 
% Fine the amn
len=length(mn);
amn=zeros(1,len);
for  i=1:len
    m=mn(i,1);
    n=mn(i,2);
    amn(i)=(16*q/(m*n*D*pi^6))*(1/((m/a)^2+(n/b)^2)^2); % amn(i) storage the array
end
% Fine the wmn
wmn = zeros(size(X,1),size(X,2),len) ;    % preallocation 
for i=1:len
    m=mn(i,1);
    n=mn(i,2);
    wmn(:,:,i)=amn(i).*((sin(m.*pi.*X./a)).*(sin(n.*pi.*Y./b))); 
end
 Combine=sum(wmn(:,:,1:4),3) ;   % use the function sum 

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KSSV 2021-6-8

在 MATLAB Online 中打开

Type error:

Replace

Combine=sum(wmn(:,:,1:4),[],3) ;

with

Combine=sum(wmn(:,:,1:4),3) ;

Edited the answer.

Mark 2021-6-8

It works! Thank you very much!

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How do I get the combination of cell array "wmn" and set up the preallocation of "wmn"

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How do I get the combination of cell array "wmn" and set up the preallocation of "wmn"

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