curvature of mode shape

Can you please help me how to write this code?

I have x=[...]

y=[....]

i=size(x)

and need to calculate r[...]=y(i+1)+y(i-1)-y(i)/h^2

h = x(i)-x(i-1)

Answer 1

[KSSV]

Already you have written what you want and it should be bit placed properly. Let y be your array.

n = length(y) ; 
r = zeros(n-2,1) ; 
for i = 2:n-1
    h = x(i)-x(i-1) ; 
    r(i) = (y(i+1)+y(i-1)-y(i))/h^2
end

[Shohreh Alaedini]

Thank you,