make several matrices in a for loop ERROR

Hi,

When i try to run the next for loop i get: (i display here the variables involved.

Unable to perform assignment because brace indexing is not supported for variables of this type.

Error in A******a (line 41)

k{i}= [E*A/long(i) 0 -E*A/long(i) 0

i would like (in this case to get three similar matrices

Hope someone can help. Thanks in advance

element =
     1     2     1
     2     3     1
     3     4     1

>> 1:size(element,1)
ans =
     1     2     3

E = 2040000

A = 4

>> long
long =
    5.0000    4.1231    5.0000
    
for i = 1:size(element,1)
    k{i}= [E*A/long(i) 0 -E*A/long(i) 0
          0            0 0            0
          -E*A/long(i) 0 E*A/long(i)  0
          0            0 0            0];
end

Answer 1

[Image Analyst]

This runs without error:

element = [
    1     2     1
    2     3     1
    3     4     1]
[rows, columns] = size(element)
ramp =  1:rows
E = 2040000
A = 4
long = [5.0000, 4.1231, 5.0000]
for ii = 1 : rows
    k{ii}= [E*A/long(ii) 0 -E*A/long(ii) 0
        0, 0, 0, 0
        -E*A/long(ii), 0, E*A/long(ii),  0
        0, 0, 0, 0];
end
celldisp(k)

Answer 2

[KSSV]

You have to initialize k as a cell.

element = [ 1     2     1
     2     3     1
     3     4     1] ;

E = 2040000 ;
long = [5.0000    4.1231    5.0000];
A = 4 ;

k = cell(size(element,1),1) ; 
    
for i = 1:size(element,1)
    k{i}= [E*A/long(i) 0 -E*A/long(i) 0
          0            0 0            0
          -E*A/long(i) 0 E*A/long(i)  0
          0            0 0            0];
end

It looks like you have initilized k as a 3D matrix, but you have indexed it as a cell. So you got the error.

I would suggest you to use:

    element = [ 1     2     1
     2     3     1
     3     4     1] ;

E = 2040000 ;
long = [5.0000    4.1231    5.0000];
A = 4 ;

k = zeros(4,4,3) ; 
    
for i = 1:size(element,1)
    k(:,:,i)= [E*A/long(i) 0 -E*A/long(i) 0
          0            0 0            0
          -E*A/long(i) 0 E*A/long(i)  0
          0            0 0            0];
end