MINERVA superseeded IF/Prolog.
Please see
http://www.ifcomputer.co.jp/MINERVA
for details.
We discontinued to sell IF/Prolog Dec 31. 2003.
Dedicated technical support for IF/Prolog ended Dec 31 2008.
This site is maintained as a community service only.
To illustrate finite domain constraints we
consider the classic "SEND MORE MONEY" prob-
lem where the three words represent a sum
(SEND + MORE = MONEY) and each letter a
variable which takes one of the integers 0 to 9.
Traditionally this problem takes a considerable
amount of search time to find the solution by
considering all possible integer values for
each variable in turn. Using constraints, the values
are propagated and the solution is calculated directly.
:- import(const_domain).
send([[S,E,N,D], [M,O,R,E], [M,O,N,E,Y]]) :-
Digits = [S,E,N,D,M,O,R,Y],
Carries = [C1,C2,C3,C4],
Digits in 0..9,
Carries in 0..1,
M ?= C4,
O + 10 * C4 ?= M + S + C3,
N + 10 * C3 ?= O + E + C2,
E + 10 * C2 ?= R + N + C1,
Y + 10 * C1 ?= E + D,
M ?>= 1,
S ?>= 1,
all_distinct(Digits),
label(Digits).
[user] ?- send(X).
X = [[9,5,6,7],[1,0,8,5],[1,0,6,5,2]]
yes
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