1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Interpolation in matlab

  1. Oct 25, 2009 #1
    1. The problem statement, all variables and given/known data

    If i have an interpolation formula, say:

    [tex]y(t_i)=3+h\sum^i_{j=1}jy(t_j)[/tex]

    where i=0 to n
    h=(a+b)/n
    ti=i*h
    and
    when i=0, we have: y(t0)=0.

    How would i write a code to find y(ti)?

    2. Relevant equations



    3. The attempt at a solution

    function y=examp(a,b,n)
    h=(a+b)/n
    for i=1:n+1
    t(i)=(i-1)*h
    for j=1:i+1

    and now im stuck because i dont know how write a code that uses the previous value of y to compute the next value of y.
     
  2. jcsd
  3. Nov 3, 2009 #2
    Before the first loop, I would set up the y's(actually, it would be faster for your code to init the t's to zeros to, but unless n is very large it shouldn't matter):

    y = zeros(n+1,1)

    Then in the loop it would be something like
    y(j) = 3 + sum( y(1:j-1).*(1:j-1) )

    the .* does an element-wise product
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook