Re: Testable Predictions by HdB
- From: Han de Bruijn <Han.deBruijn@xxxxxxxxxxxxxx>
- Date: Fri, 07 Oct 2005 10:24:33 +0200
*** T. Winter wrote:
I am now trying to thoroughly look at it, and much of it does not make sense to me. (And I tried to implement it, but the results were completely wrong.) First question. Given a set of t_k and function values f_k, you define a continuation:
f(t) = sum{k} f_k.exp(-[(t - t_k)/sigma]^2/2)
Yes. That's a consequence of my sloppy documentation. At first, the t_k should be _equidistant_ (: essential). And a norm = 1/sqrt(2.pi.sigma) (: the "well-known constant", see below) must be included:
f(t) = norm . sum{k} f_k.exp(-[(t - t_k)/sigma]^2/2)in what way is that a continuation? When I fill in any t_k for t, it is not f_k that comes out. (You also mention a well-known constant in that context. Well, that constant is not known to me.)
That's true: f_k is _not_ equal to f(t_k) . That's the penalty you pay for the ease later on. But if you choose the sigma = 2.|t_(k+1) - t_k| then the approximation should be good where f''(x) is not large. Order of magnitude of the error = f''(x).sigma^2/2 . Any comments on my non- standard terminology would be welcome as well. And no, I don't have a decent theory (in my head) for non-equidistant samples. Not yet. Hope this helps, anyway.
Han de Bruijn
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