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Prolog is well suited for small (toy) combinatorial optimization, useless in practice. It's no wonder the whole 5GL idea tanked mainly because Prolog just could

by bitL 9y ago

Prolog is well suited for small (toy) combinatorial optimization, useless in practice. It's no wonder the whole 5GL idea tanked mainly because Prolog just couldn't deliver. Yes, I had fun with SWI Prolog and 2nd order abstractions, but in no way I am going to use it on large problems, though I might implement pieces of Warren's Abstract Machine when I see fit.

zmonx 9y ago
SWI-Prolog lacks a commercial-grade constraint solver that is sufficiently efficient for the tasks you might have tried. If you are interested in applying constraint solving for very complex combinatorial tasks, consider trying a Prolog system with more efficient constraint solvers which are routinely used in industry. Note that SWI-Prolog is not based on the WAM either.
- saosebastiao 9y ago
  The only one I know of is sicstus prolog and it hasn't kept up with the state of the art, such as OR-Tools and HaifaCSP, both of which are available from a FlatZinc language interface. Prolog has some benefits in its more declarative nature, but it really constrains you because it forces you to use an entire prolog implementation, when all you really need is an interface to a solver.
  - zmonx 9y ago
    Conversely, what if you really need a Prolog system or indeed any general purpose programming language, but only have an interface to a more limited solver? I find this even more constrained. As technology progresses, interfaces to other solvers that appear from time to time become available in Prolog systems if enough users demand it. For many cases, a Prolog system is already more than sufficient on its own, and is far more flexible than specialized tools which can still be provided as add-ons to Prolog. It is straight-forward to use only a specific subset of Prolog, if that is all you need. In contrast, it is generally impossible to use basic features of Prolog, such as backtracking and logical variables, in more specialized tools and solvers.

by bitL 9y ago

zmonx 9y ago

SWI-Prolog lacks a commercial-grade constraint solver that is sufficiently efficient for the tasks you might have tried. If you are interested in applying constraint solving for very complex combinatorial tasks, consider trying a Prolog system with more efficient constraint solvers which are routinely used in industry. Note that SWI-Prolog is not based on the WAM either.

saosebastiao 9y ago
The only one I know of is sicstus prolog and it hasn't kept up with the state of the art, such as OR-Tools and HaifaCSP, both of which are available from a FlatZinc language interface. Prolog has some benefits in its more declarative nature, but it really constrains you because it forces you to use an entire prolog implementation, when all you really need is an interface to a solver.
- zmonx 9y ago
  Conversely, what if you really need a Prolog system or indeed any general purpose programming language, but only have an interface to a more limited solver? I find this even more constrained. As technology progresses, interfaces to other solvers that appear from time to time become available in Prolog systems if enough users demand it. For many cases, a Prolog system is already more than sufficient on its own, and is far more flexible than specialized tools which can still be provided as add-ons to Prolog. It is straight-forward to use only a specific subset of Prolog, if that is all you need. In contrast, it is generally impossible to use basic features of Prolog, such as backtracking and logical variables, in more specialized tools and solvers.