Does this give you what you want:
function make_interp(x, y)
y = copy(y)
function interp(x2)
@assert x2 > x[1] && x2 < x[end]
i = 1
while x[i] < x2; i += 1; end
(x[i] - x2) * y[i-1] + (x2 - x[i-1]) * y[i]
end
end
x = [1,2,3,4,5]
y = [x2^2 for x2 in x]
my_interp = make_interp(x, y)
println(my_interp(2.1)) # prints 4.5
y[2] = 5
println(my_interp(2.1)) # prints 4.5
On Tue, Feb 25, 2014 at 4:01 PM, Marek Gagolewski
<[email protected]> wrote:
> Dear Andrew,
>
> Nope, unfortunately it's not what I am trying to achieve. The code you've
> kindly (let's forget the interpolation task, what I really meant is some
> programming construct, so it's OK with no delta_x) submitted gives:
>
> my_interp = make_interp(x, y)
> println(my_interp(2.1)) # prints 4.5
>
> y[2] = 5
> println(my_interp(2.1)) # prints 5.4
>
> and I also would like to get 4.5 in the second case.
>
> All the best,
> Marek
