From Newsgroup: comp.lang.java.programmer


Railgun CLP is a portable constraint solver library,
developed in connection with Dogelog Player. It requires
nothing more than ISO core standard Prolog and shows
an amazing performance. We added basic indexicals.

To compare our basic indexicals solutions we use 3
magic square problems against the Z3 SMT solver and
the Gecode solver. It turns out that Railgun v11 was
6-7x times faster than Z3 and 2x times slower than
Gecode. As a 100% Prolog solution we still have some

headroom, for example we could realize a native between/3.

See also:

Basic Indexicals for Railgun CLP(Z) https://qiita.com/j4n_bur53/items/ddda3ba5186acddae91b

Mild Shock schrieb:

Railgun CLP is a portable constraint solver
library, developed in connection with Dogelog
Player. It requires nothing more than ISO core
standard Prolog and shows an amazing performance.
We added full multiply.

We discussed full multiply which can extend the
constraint solver from positive intervals, to
negative and zero centered intervals. The realized
compilation scheme does incure a small penality
and in examples such as Pythago and Euler we still
see a 5x to 15x speed-up against SWI-Prolog.

See also:

Full Multiply in Railgun CLP
https://medium.com/2989/26eb4445e5b1

Mild Shock schrieb:

Dear All,

We are happy to announce a new edition
of the Dogelog Player:

- Enhanced library(compat):
We introduced a new built-in occurs_check/2.
The predicate could be bootstrapped from
unify_with_occurs_check/2 via occurs_check(V,T)
:- \+ unify_with_occurs_check(V, T). But
tapping into the native check gives better performance.

- Enhanced library(math):
We introduced sqrtrem/3 and isqrt/2 built-ins,
for integer square root. The former is a predicate
that also computes a reminder, and the later is
an evaluable predicate, that suppresses the reminder.

- New Railgun CLP:
What began as a sport in December 2025 to explore
a constraint solver that only uses ISO core
standard Prolog. Is now a full project with
iterative milestones. In this release we provide
the basic vocabulary of CLP(FD), and an enhanced
solver that uses min/max based partial consistency.

Have Fun!

Jan Burse, https://www.herbrand.ai/ , 22.01.2026

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