Lagrange Interpolation code error

Please tell me whats wrong with this code, it was given by the professor but when i try to use it it gives me errors.

if true 
function yi = LagrangeInterp(x,y,xi)

x = [ -0.200 0.000 0.200 0.400 0.600 0.800 1.000]; y = [ 0.5000 1.0000 0.5000 0.2000 0.1000 0.0588 0.0385 ];

n = length (x) ; L = zeros (1,n) ; for i =1:n, L(i) = 1; for j = 1:n, if j ~= i, L(i) = L(i) * (xi - x(j)) / (x(i) - x(j)); end end end

yi = sum(y.*L);

    % code

end

*Not enough input values *Error in line 3

I want to find Y values when x= 0.3 & x = 0.9

please give me a correct method to find this .

thank you

Answer 1

[Roger Stafford]

The message is caused by your not defining or properly entering the value of vector 'xi'.