arbtt feedback

[Joachim Breitner]

Hi,

Am Sonntag, den 16.09.2012, 13:54 -0400 schrieb Gwern Branwen:
> > GHC in testing is at 7.4. But 0.6.2-1 should have been compiled with
> > that.
> 
> /shrug
> 
> When I run update && upgrade, GHC is in the kept back list so far.

Have you tried dist-upgrade? (I am part of the Debian team that
maintains ghc, so I’m interested in user reports).

> > I looked at the code again and the problem is that it currently keeps
> > track of the whole list for several reasons:
> >  * There can be multiple report being processed.
> >  * Some global data (i.e. total number of records) is calculated first
> > and then shared between possibly multiple report passes.
> >  * Some reports also refer to the non-selected time (“% of total time
> > selected”). So making arbtt-stats O(1) is a non-trivial refactoring.
> 
> Why would either of the latter two force retention of the full
> dataset? An integer counter like 'total number of records' should be
> computable without retaining the list, and likewise integer counters
> for selected or non-selected time.

Yes, each individual value could be calculated lazily, but not first one
and then the other. This is basically the same problem as in
	let xs = [1..100000000]
	in (last xs, length xs)
I could, for each traversal, re-open the file, re-parse it and lazily
process it. Or I could manually merge the various computations into one
fold, but that looks tedious. I should look what support libraries like
iteratee provide for that.


Greetings,
Joachim

-- 
Joachim Breitner
  e-Mail: mail at joachim-breitner.de
  Homepage: http://www.joachim-breitner.de
  Jabber-ID: nomeata at joachim-breitner.de
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