The following predicates all take as (optional) argument a list Options which can be used to change the default behavior of the execution. This list may contain zero or more of the following:
data_file(MznDatFile)--data option.
parameters(ListOfParDef)--data option.
post(Boolean)true or false. If true
(the default), the constraints of the MiniZinc program are posted
directly and a separate call to fzn_post/1 (see FlatZinc Exported Predicates) is not necessary. (Only usable with
mzn_load_file/3 and mzn_load_model/3).
solutions(NumberOfSolutions)all. Describes the number of solutions to search for,
default is 1. (Only usable with mzn_run_file/2 and
mzn_run_model/2).
variables(ListOfVarDef)mzn_load_file/3 and mzn_load_model/3).
The first two predicates can be used to run a MiniZinc program in one go.
mzn_run_file(+MznFile)mzn_run_file(+MznFile, +Options)data_file/1,
parameters/1, and solutions/1.) Runs the MiniZinc
program in MznFile and writes the result on the current output
stream. This is done by first calling the external
MiniZinc-to-FlatZinc translator and parsing the output of that
program with fzn_run_stream/[1,2] (see FlatZinc Exported Predicates). Fails if the constraints of the MiniZinc program are
inconsistent.
Exceptions:
all.
mzn_run_model(+MznModel)mzn_run_model(+MznModel, +Options)data_file/1, parameters/1, and
solutions/1.) Runs the MiniZinc program specified by
MznModel and writes the result on the current output stream. This
is done by first calling the external MiniZinc-to-FlatZinc translator
and parsing the output of that program 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.
Exceptions:
all.
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.dat'))]).
Since library('zinc/examples/queen4.dat') 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]
1 solution found
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]
2 solutions found
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)data_file/1,
parameters/1, post/1, and variables/1.) Initializes
a FlatZinc state FznState with respect to MznFile. May
fail if post(true) and the constraints are inconsistent.
Exceptions:
variables/1
option is not an identifier of FznState.
mzn_load_model(+MznModel, -FznState)mzn_load_model(+MznModel, +Options, -FznState)mzn_run_model/[1,2] above and Options is a
list of options as described above. (Usable options are
data_file/1, parameters/1, post/1, and
variables/1.) Initializes a FlatZinc state FznState with
respect to MznModel. May fail if post(true) and the
constraints are inconsistent.
Exceptions:
variables/1
option is not an identifier of FznState.
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:
A solution to the 4 Queens problem: [2, 4, 1, 3]
The final predicate can be used to translate a MiniZinc file to a FlatZinc by a direct call to the MiniZinc-to-FlatZinc translator.
mzn_to_fzn(+MznFile, +FznFile)mzn_to_fzn(+MznFile, +Options, +FznFile)data_file/1 and
parameters/1.) Calls the external MiniZinc-to-FlatZinc translator
which result is written to FznFile.
Exceptions: