Plan Simulator

[Daniel Schwartz]

Has anyone ever created a system that will simulate the execution of a plan generated by Fast Downward?

[Robert P. Goldman]

Apologies for answering a question with another, but … it depends: what do you mean by simulate?

If you mean simulate the execution of a PDDL plan under the assumptions of classical planning (static environment, perfect action models, and complete information), then yes, there are many such programs, starting with VAL (on github).  Every (at least) forward search planner does this implicitly.

If you want to relax any of these assumptions, yes, there probably are, but then you need to be very clear about what assumptions you are relaxing, and how realistic you want the domain dynamics to be.

Happy Thanksgiving to those who celebrate.

[Robert P. Goldman]

P.S. The more realistic you want to be, the more likely it is that your simulator will be domain-dependent.

[Daniel Schwartz]

Hello Robert,

 

Thanks for the quick reply.  I found VAL on GitHub and will take a look.  You say that are many such simulators.  Can you tell me where I might find them?

 

Happy Thanksgiving to you, as well.  I’m writing this while watching over a turkey cooking.

 

Dan Schwartz

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[Robert Goldman]

If I recall correctly, cpddl has one, and there’s Patrik Haslum’s INVAL. Try searching for pddl validator instead of simulator, and you should find more

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[Daniel Schwartz]

Thanks.  I appreciate this.  I found cpddl and INVAL, plus another one.  I’ll take a look.  Somehow it didn’t seem to me that a validator would be a simulator, but maybe so.

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[Malte Helmert]

I think there are simulation capabilities both in the planning.domains
infrastructure and in the VSCode plugin by Jan Dolejší.

For planing.domains (http://planning.domains/), I think this is somehow
integrated in the editor or available as a plugin. I think Christian
Muise would be the best person to ask.

I haven't seen Jan in a while, so I don't know how active his project
is, but here you can find his github, which also has a plan
visualization project: https://github.com/jan-dolejsi.

This is more of a general planning question than a Fast Downward
question, so a good place to ask would be the planning community slack,
linked from http://planning.domains/about.

Best,
Malte

On 28.11.25 00:40, Daniel Schwartz wrote:
> Thanks.  I appreciate this.  I found cpddl and INVAL, plus another one.
> I’ll take a look.  Somehow it didn’t seem to me that a validator would
> be a simulator, but maybe so.
>

> *From:*fast-d...@googlegroups.com <fast-d...@googlegroups.com>
> *On Behalf Of *Robert Goldman
> *Sent:* Thursday, November 27, 2025 2:38 PM
> *To:* fast-d...@googlegroups.com
> *Subject:* Re: [Fast Downward] Re: Plan Simulator

>
> If I recall correctly, cpddl has one, and there’s Patrik Haslum’s INVAL.
> Try searching for pddl validator instead of simulator, and you should
> find more
>
> On Thu, Nov 27, 2025 at 12:30 Daniel Schwartz <d...@danielgschwartz.com
> <mailto:d...@danielgschwartz.com>> wrote:
>
> Hello Robert,
>
> Thanks for the quick reply.  I found VAL on GitHub and will take a
> look.  You say that are many such simulators.  Can you tell me where
> I might find them?
>
> Happy Thanksgiving to you, as well.  I’m writing this while watching
> over a turkey cooking.
>
> Dan Schwartz
>

> *From:*fast-d...@googlegroups.com <mailto:fast-
> down...@googlegroups.com> <fast-d...@googlegroups.com
> <mailto:fast-d...@googlegroups.com>> *On Behalf Of *Robert P.
> Goldman
> *Sent:* Thursday, November 27, 2025 12:52 PM
> *To:* Fast Downward <fast-d...@googlegroups.com <mailto:fast-
> down...@googlegroups.com>>
> *Subject:* [Fast Downward] Re: Plan Simulator

>
> P.S. The more realistic you want to be, the more likely it is that
> your simulator will be domain-dependent.
>
> On Thursday, November 27, 2025 at 11:50:13 AM UTC-6 Robert P.
> Goldman wrote:
>
> Apologies for answering a question with another, but … it
> depends: what do you mean by simulate?
>
> If you mean simulate the execution of a PDDL plan under the
> assumptions of classical planning (static environment, perfect
> action models, and complete information), then yes, there are
> many such programs, starting with VAL (on github).  Every (at
> least) forward search planner does this implicitly.
>

> If you want to /relax/ any of these assumptions, yes, there

> probably are, but then you need to be very clear about what
> assumptions you are relaxing, and how realistic you want the
> domain dynamics to be.
>
> Happy Thanksgiving to those who celebrate.
>
> On Thursday, November 27, 2025 at 11:39:35 AM UTC-6 Daniel
> Schwartz wrote:
>
> Has anyone ever created a system that will simulate the
> execution of a plan generated by Fast Downward?
>
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