failure to post arithmetic constraint

[Bowie Owens]

Hi,

I am having difficulty posting some simple arithmetic constraints in
GNU Prolog 1.2.8 (and 1.2.9) under x86 Linux. The problems come from
the multiplication of otherwise unconstrained variables. There does seem
to be some interaction with the vector representation of variables. As
using full AC equality forces use of the vector representation when I
would not expect it to do so.

| ?- A * X  #= Y.

no
| ?-  A+X #=< 127, A * X  #= Y.

A = _#22(0..127)
X = _#41(0..127)
Y = _#86(0..16129)

yes
| ?- A+X #>= 127, A * X  #= Y.

no
| ?- A * X  #=# Y.             

A = _#3(0..268435455)
X = _#22(0..268435455)
Y = _#41(0..127@)

yes
| ?- A+X #>= 127, A * X  #=# Y.

A = _#22(0..268435455)
X = _#41(0..268435455)
Y = _#86(0..127@)

yes
| ?- A+X #=< 127, A * X  #=# Y.

A = _#22(0..127)
X = _#41(0..127)
Y = _#86(0..127)

yes


-- Bowie Owens

CSIRO Mathematical & Information Sciences
phone : +61 3 9545 8055
email : address@hidden