Thanks Thomas,

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Hi,

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Hi there,

I'm currently evaluating powerloom for research in the context of an agent platform.

I've read through all documentation of powerloom so far and I think it's certainly powerful enough
to use it for our purposes, certainly for all the standard logic.
I do have a question however on producing solutions and alternatives. The only recursion
example I found in Powerloom used transitivity rules (parent/ancestor example and the RCC8 KB).
Unfortunately, my problem cannot be used with transitivity.

The problem I have is:

- Someone states input need X.
- Programs provide one single output
- In order to produce the output, a program may have 0-n input needs, which need to be resolved
with outputs from other programs.
- Those programs providing these outputs in their turn may have 0-n input needs themselves.


The required output is a list of acceptable solutions that, in their combination, can provide
the output. I imagine that the only way to do this properly is through recursion somehow.
I do however have two alternatives there:
- I can do this in Java and just maintain the tree myself
- I may be able to rely on Powerloom to produce these alternatives, but I don't know what to look for.
(many instances of programs may exist, so including a similar instance is actually a different solution).


So that's the question basically. Can powerloom produce a list of entities that together form the solution,
based on some constraints that are set on the production of this list and present each acceptable, but minimal
solution individually? I'm not asking for a piece of code, just what I need to look for to realize this.


Rgds,

G>


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Thanks Hans, this has certainly been helpful. 

The justifications example certainly looks very complex to me and your second point made
me realize I'd be better off maintaining my own tree in the host code. Then I can choose which
branches to explore based on a number of different algorithms (breadth-first, iterative deepening, best-first, etc.).
I think I'll go down that route for now at least.


Before looking at powerloom, I looked at JSHOP2. JSHOP2 can solve planning problems, but it requires compilation
of the KB and the language is certainly not as rich as powerloom's for the expression of particular relations and so forth.
Is powerloom well suited for planning problems in general? I haven't found any demos or tutorials that
show how it's used for those kinds of problems.

Rgds,

Gerard


> From: hans <at> ISI.EDU
> Date: Thu, 25 Mar 2010 13:18:24 -0800
> To: toonstge <at> hotmail.com
> CC: powerloom-forum <at> ISI.EDU
> Subject: Re: Powerloom, a first stab...

> (2) minimality: you can do a "retrieve all" and PowerLoom will try to
> generate all possible solutions. If you have some kind of cost
> function, you'd compute that cost for each solution and then select
> the one with the smallest one (e.g., make the cost an output argument
> and do a :sort-by :values in the retrieve). However, if there is a
> potentially large number of solutions, you might want to do something
> smarter than that by cutting off partial solutions that can't improve
> on what you already have. That, however, you would have to do in
> code. You might also have more complex subsumption relationships
> between solutions which might require a somewhat more sophisticated
> approach.
>
> Hope that helps,
>
> Hans
>
> >>>>> Gerard Toonstra <toonstge <at> hotmail.com> writes:
>
> > Hi there,
>
> > I'm currently evaluating powerloom for research in the context of an agent platform.
>
> > I've read through all documentation of powerloom so far and I think it's certainly powerful enough
> > to use it for our purposes, certainly for all the standard logic.
> > I do have a question however on producing solutions and alternatives. The only recursion
> > example I found in Powerloom used transitivity rules (parent/ancestor example and the RCC8 KB).
> > Unfortunately, my problem cannot be used with transitivity.
>
> > The problem I have is:
>
> > So that's the question basically. Can powerloom produce a list of entities that together form the solution,
> > based on some constraints that are set on the production of this list and present each acceptable, but minimal
> > solution individually? I'm not asking for a piece of code, just what I need to look for to realize this.
>
> > Rgds,
>
> G>
>
> > _________________________________________________________________
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