The first two predicates can be used to run a MiniZinc program in one go.
mzn_run_file(+MznFile)
mzn_run_file(+MznFile, +Options)
MznFile is a MiniZinc program file and Options is
a list of options; see see Zinc Options. Runs the
MiniZinc program on MznFile, and writes the result onto
the file given in the option/1
option if given, or onto the
current output stream otherwise. This is done by first calling
minizinc -c
, and then interpreting its output with
fzn_run_stream/[1,2]
(see FlatZinc Exported Predicates). Fails if the constraints of the MiniZinc program
are inconsistent.
mzn_run_model(+MznModel)
mzn_run_model(+MznModel, +Options)
MznModel is a MiniZinc program specified by a list of
strings as explained below and Options is a list of options; see
see Zinc Options. Runs the MiniZinc program
MznModel, and writes the result onto the file given in the
option/1
option if given, or onto the current output stream
otherwise. This is done by first calling minizinc -c
and
interpreting its output with fzn_run_stream/[1,2]
(see FlatZinc Exported Predicates). The MiniZinc program
specification MznModel must be a list of strings (list of
character codes) where each element must specify one line of the
MiniZinc program. For example, a MiniZinc program for
the N Queens problem can be specified as follows:
NQueens = ["int: n;", "array [1..n] of var 1..n: q;", "constraint forall (i in 1..n, j in i+1..n)", "(q[i] != q[j] /\\", "q[i] + i != q[j] + j /\\", "q[i] - i != q[j] - j);", "solve satisfy;", "output [\"A solution to the \", show(n),", "\" Queens problem: \", show(q), \"\\n\"];"]
Note that backslashes and double quotes must be escaped with an additional backslash.
Consider the following MiniZinc program for solving the N Queens problem
located in library('zinc/examples/queen.mzn')
:
queen.mzn
int: n; array [1..n] of var 1..n: q; constraint forall (i in 1..n, j in i+1..n) ( q[i] != q[j] /\ q[i] + i != q[j] + j /\ q[i] - i != q[j] - j ); solve satisfy; output ["A solution to the ", show(n), " Queens problem: ", show(q), "\n"];
Consider now the following goal at the Prolog top level:
| ?- mzn_run_file(library('zinc/examples/queen'), [data_file(library('zinc/examples/queen4.dzn'))]).
Since library('zinc/examples/queen4.dzn')
contains the single
line
n = 4;
the following is written on the current output stream:
A solution to the 4 Queens problem: [2,4,1,3] ----------
The initialization n = 4
can also be passed using the
parameter/1
option. So the following goal is equivalent to the
one above:
| ?- mzn_run_file(library('zinc/examples/queen'), [parameters([n=4])]).
Finally, the following goal finds all solutions to the 4 Queens problem:
| ?- mzn_run_file(library('zinc/examples/queen'), [parameters([n=4]), solutions(all)]).
Given this goal, the following is written on the current output stream:
A solution to the 4 Queens problem: [2,4,1,3] ---------- A solution to the 4 Queens problem: [3,1,4,2] ---------- ==========
The next two predicates can be used to construct a FlatZinc state (see FlatZinc Exported Predicates).
mzn_load_file(+MznFile, -FznState)
mzn_load_file(+MznFile, +Options, -FznState)
MznFile is a MiniZinc program file and Options is a list
of options; see see Zinc Options. Initializes a FlatZinc state
FznState with respect to MznFile. May fail if
post(true)
and the constraints are inconsistent.
mzn_load_model(+MznModel, -FznState)
mzn_load_model(+MznModel, +Options, -FznState)
MznModel is a MiniZinc program specified by a list of
strings as explained for mzn_run_model/[1,2]
above and
Options is a list of options; see see Zinc Options.
Initializes a FlatZinc state FznState with respect to
MznModel. May fail if post(true)
and the constraints are
inconsistent.
The following Prolog goal constructs a FlatZinc state representing the 4 Queens problem:
| ?- mzn_load_file(library('zinc/examples/queen'), [parameters([n=4])], Queen4State).
See FlatZinc Exported Predicates for more information on FlatZinc
states and how they can be queried. A very useful option to
mzn_load_file/3
and mzn_load_model/3
is the
variables/1
option, which can be used to unify values of MiniZinc
identifiers with Prolog variables (this option can be used in place of
several calls to fzn_identifier/3
). For example, the following
goal posts an additional symmetry breaking constraint and labels the
variables using a Prolog goal that finds all remaining solutions to the
4 Queens problem:
| ?- mzn_load_file(library('zinc/examples/queen'), [parameters([n=4]), variables([q=Q])], Queen4State), Q = [Q1, Q2|_], Q1 #< Q2, findall(_, (labeling([], Q), fzn_output(Queen4State)), _).
Given this goal, the following is written on the current output stream:
q = array1d(1..4, [2,4,1,3]); ----------
Finally, the following predicate can be used to translate a
MiniZinc file to a FlatZinc by a direct call to
minizinc -c
.
mzn_to_fzn(+MznFile, +FznFile)
mzn_to_fzn(+MznFile, +Options, +FznFile)
MznFile is a MiniZinc program file and Options is
a list of options; see see Zinc Options. Calls minizinc -c
,
the result of which is written to FznFile.