Index exceeds array bounds error

Hi there I have a problem with the code below. I am trying to run a for loop for n=100 times where E is a constant and dnew is a 100x1 matrix. I am hoping for this to create S_FEM, an additional 100x1 matrix. However when trying to run I get the error "Index exceeds array bounds". How can I fix this?

for i = 1:n  
    S_FEM(i) = (E*(dnew(i+1)-dnew(i)))/l;    
end

S_FEM(n+1) = S_FEM(n); 

Answer 1

[Star Strider]

Consider:

‘n=100’

‘dnew is a 100x1 matrix’

and you are addressing:

dnew(i+1)

that does not exist.

Try this instead:

for i = 1:n-1  
    S_FEM(i) = (E*(dnew(i+1)-dnew(i)))/l;    
end
S_FEM(n+1) = S_FEM(n);

Answer 2

[madhan ravi]

When the loop iterator becomes n which is 100 , what happens is dnew(i+1) tries to grab 101’st element from the variable dnew which doesn’t exist.

So anyway you don’t need a loop to acquire this task:

S_FEM = E*diff(dnew)/l;
S_FEM = [S_FEM;S_FEM(n)]