for loops not working

Asked by sriram amarnath

sriram amarnath (view profile)

on 24 Jun 2019
Latest activity Commented on by sriram amarnath

on 24 Jun 2019

madhan ravi (view profile)

The below code is to calculate the modes on a plate. The for loops are not using all the values of m & n
% Modes on a plate
Lx=0.286; % length of plate(m)
Lz=0.198; % breadth of plate(m)
for m = 1:1000 % mode numbers
for n = 1:10
func=((n.*pi)./Lx).^2 +((m.*pi)./Lz).^2;% summation function n=1:10 & m= 1:1000
end
end

dpb

dpb (view profile)

on 24 Jun 2019
I'm sure the loop runs 10,000 times--only you don't do anything inside the loop except write over the same variable with each computed value in succession so all you get in the end is the very last value.
sriram amarnath

sriram amarnath (view profile)

on 24 Jun 2019
So how do i get a matrix of every value?

madhan ravi (view profile)

on 24 Jun 2019
Edited by madhan ravi

madhan ravi (view profile)

on 24 Jun 2019

The same goal can be achieved trivially using meshgrid() or ndgrid() without a loop:
% Modes on a plate
Lx=0.286; % length of plate(m)
Lz=0.198; % breadth of plate(m)
n=10;
m=1000;
[Y,X]= ndgrid(1:m,1:n);
func=(X*pi/Lx).^2 +(Y*pi/Lz).^2;
But the modication in your code is as follows:
func = zeros(1000,10); % before loop
func(m,n) = ... %just add (m,n) next to func inside the loop

sriram amarnath

on 24 Jun 2019