solve tally (or: solve count)

[Pierre-Flener]

Is there an easy way to mimic the afaik-non-existing-yet "solve tally" objective (one could call it "solve count", but "count" is already a predicate/function) for just counting (rather than displaying) solutions (to a CSP)?

One can of course, from the command line, pipe the output into wc (word count), subtract 1 from the line count (due to the final line starting with =====) and divide by 2 (in order to avoid counting all ----------), but that's clumsy.

Btw, what combination of values for the command-line options "soln-sep" and "soln-comma" eliminates the apparently forced line between two consecutive displayed solutions (so that one can skip the division by 2 above)?

[schutta]

Instead of wc you could use awk for piping. For example:

$ minizinc a.mzn -a | awk '/^----------/ {a++;print "% sol_no = " a ";"} {print}'

The output looks as follows

x = 1;
y = 5;
% sol_no = 1;
----------
x = 1;
y = 6;
% sol_no = 2;
----------
x = 2;
y = 6;
% sol_no = 3;
----------
==========

for this model.

var 1..6: x :: add_to_output;
var 1..6: y :: add_to_output;
constraint x + 3 < y;
solve satisfy;

Instead of declaring the "solve tally" inside the model, imo, it is better to add an option to minizinc and solns2out similar to --output-time, which adds the "solve tally" in the output as a comment.

[Pierre-Flener]

Thanks (it's been some time I played with awk)!

I like the suggested idea of adding a new command-line option for tallying, so that's for my wish list!

[guidotack]

The next release will print a statistics line with the number of solutions after solving has finished (enabled using the -s command line switch).