Unable to perform assignment because the left and right sides have a different number of elements

I have the follwing matlab code. After excecuting it, error is displayed as "Unable to perform assignment because the left and right sides have a different number of elements." Kindly help me out.

k12=200;
k34=500;
K=zeros(4,4);
a=2:0.02:9;
b=1:length(a);
kc(b)=2:0.02:9;
for b=1:length(a)
    kc(b)=2:0.02:9;
    K(b)=[k12 -k12 0 0;-k12 kc(b)+k12 -kc(b) 0;0 -kc(b) k34+kc(b) -k34;0 0 -k34 k34];
end

Answer 1

[Image Analyst]

kc(b) is a single element because b is a single number between 1 and length(a).

2:0.02:9 is a 351 long row vector, NOT a single number.

You cannot stuff 351 numbers into an element meant to take only one number.

K(b) is a single element because b is a single number between 1 and length(a).

[k12 -k12 0 0;-k12 kc(b)+k12 -kc(b) 0;0 -kc(b) k34+kc(b) -k34;0 0 -k34 k34]; is a 4-by-4 matrix, NOT a single number.

You cannot stuff a 4x4 matrix into an element meant to take only one number.

[venkatesu u]

Hi

Thanks for your response. Can you kindly provide exact code that i should follow?

[Image Analyst]

No because I don't know what your thought process is. Why are you trying to stuff a 4x4 matrix into a single element? Or did you not intend to do that? If so, what DID you intend?

[venkatesu u]

Hi

I intend to find the eigenvalues & eigenvectors of the matrix [K(b)] with a continuous variation of b. Here b = 2:0.02:9. So that 2 Dimensional plot of K to b can be done. Kindly help me out with this.

[Walter Roberson]

k12=200;
k34=500;
a=2:0.02:9;
num_a = length(a);
K = cell(num_a,1);
Kc = cell(num_a,1);
b = 1:num_a;
kc(b) = repmat({a}, num_a, 1);
for b=1:num_a;
    kc{b} = a;
    K{b} = [k12 -k12 0 0;-k12 kc{b}+k12 -kc{b} 0;0 -kc{b} k34+kc{b} -k34;0 0 -k34 k34];
end

Error using vertcat
Dimensions of arrays being concatenated are not consistent.

That is about as far as you can get. You are storing all of a into the current kc location, and so when you recall the current kc value in the second row of K, then you get all of those a values, and the sizes of the rows no longer match up.

Have you considered the possibility that you might only want to work with one single a value at a time instead of with all of them ?

[venkatesu u]

Hi

I need to work with all of the values. I tried in another way with the following code.

clear all

clc

kc=[1 2 3 4 5 6 7 8 9 0];

k12=200;

k34=300;

new1=1:1:10;

for h1=1:length(new1);

for l1=1:length(new1);

K(h1,l1)=[k12 -k12 0 0;-k12 kc(h1,l1)+k12 -kc(h1,l1) 0;0 -kc(h1,l1) k34+kc(h1,l1) -k34;0 0 -k34 k34];

end

end

But it shows the following error after execution in MATLAB.

"Unable to perform assignment because the indices on the left side are not compatible with the size of the right side"

Kindly help me with this.

[Image Analyst]

Same problem and same question. You're trying to stick a 4x4 matrix into a location that can hold only one value. I don't know why you are trying to do that other than you saying you think you need to. But it's not allowed.