In the program below, the loop stops at theta(4). It will be a great help if you can please help me to rectify the error.

clear

theta(1)= input('Enter your guess:')

theta(3)= theta(1)

S1=0.5

S2=.32

S3=0.56

dx=(1/30)

for i= 2:30

    theta(i)=(theta(i+1)+theta(i-1)+S3*(dx)^2)/(S1*theta(i)*(dx)^2+S2*(dx)^2+2)

end

theta(i)

The error message is-----

 ??? Attempted to access theta(4); index out of bounds because numel(theta)=3.

Error in ==> discrtization at 9. theta(i)=(theta(i+1)+theta(i-1)+S3*

(dx)^2)/(S1*theta(i)*(dx)^2+S2*(dx)^2+2)

Answer 1

[Ben11]

Initialize your array theta and change the upper limit of your for loop like so:

theta = zeros(1,30);

theta(1)= input('Enter your guess:')

theta(3)= theta(1)

S1=0.5

S2=.32

S3=0.56

dx=(1/30)

for i= 2:size(theta,2)-1

      theta(i)=(theta(i+1)+theta(i-1)+S3*(dx)^2)/(S1*theta(i)*(dx)^2+S2*(dx)^2+2)
  end

theta(i)

[Tuhin]

Dear Ben, Thanks a ton for the reply. It is working now.

[Ben11]

great then glad to help!