Re: [eclipse-clp-users] Is referenced_record/2 related to accessing asserted clauses?

From: Joachim Schimpf <jschimpf_at_...311...>
Date: Tue, 04 Dec 2012 18:04:23 +0100
On 28/11/2012 05:01, Edwin Wirawan wrote:
> Hi Kish, Thorsten,
>
> While using a store is much faster than using dynamic clauses when we only need to access a single
> item, the performance seems similar when we need to access every single item in the store /
> asserted database.
> My code needs to do the latter, i.e. it needs to visit every item whenever it is accessing the
> database, so replacing the asserted database with a store would not seem to provide a lot of speed-up.
>
> It seems that in order to tap into the store's superior performance, I would have to use the store
> in a way such that the key of the store is not merely an edge ID, which doesn't allow the code to
> constrain the search
> through the items in the store, but rather a key that reflects some constraints that would narrow
> down the search to a subset of all the items in the store.
>
> Is there an alternative which would not involve constraining the search and therefore would still
> access every single item in the store / database, while still providing a considerable speed-up?

If you store your graph data in clauses or a "store" (which are both
persistent with respect to backtracking), then every access involves
a relatively expensive copy operation.

You should therefore consider representing your graph as a normal data
structure, which gets passed around as an argument to your predicates.
A suitable graph data structure is defined in library(graph_algorithms),
which also gives you a number of useful operations on such graphs.
There is also some visualization support for these graphs.

http://www.eclipseclp.org/doc/bips/lib/graph_algorithms/index.html
http://www.eclipseclp.org/doc/bips/lib/graphviz/index.html


-- Joachim
Received on Tue Dec 04 2012 - 17:04:58 CET

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