Re: [boost] Time Series review - 7/30-8/8

From: Matthias Troyer (troyer_at_[hidden])
Date: 2007-08-08 23:47:22

On 7 Aug 2007, at 12:06, Eric Niebler wrote:

>
> I'm sorry you ran into trouble with floating-point offsets. To be
> honest, they were added to the time_series library as a bit of an
> after-thought, and they are admittedly not a seamless addition. With
> integral offsets, runs are in fact half-open. Floating-point runs are
> not -- it's not clear what that would mean. (E.g., a delta series D  
> has
> a 42 at [3.14,3.14) -- that's a zero-width half open range! What  
> should
> D[3.14] return?) Some of the algorithms won't work with floating-point
> offsets. If you feel this part of the library needs more thought,  
> that's
> a fair assessment. I'm certain that had you used integral offsets your
> experience would have been less frustrating.
>
> I think with better docs and more strict type checking, integral and
> floating point offsets can both be supported without confusion.

Don't confuse the sparse/dense time series with piecewise constant  
functions. A delta series D has 42 at 3.14, not at any interval  
[3.14,3.14) - intervals should be used only for the piecewise  
constant functions.

Matthias