Re: [Minion-general] switches

[Chris J. <ch...@bu...>]

Thank you for your comments!

Fortunately, in the next couple of weeks Minion's documentation should
improve hugely, as a Constraint Programming Summer School is being
held in St. Andrews ( http://www-circa.mcs.st-and.ac.uk/cpss2008/ ) in
which we will be using Minion extensively. We will use your comments
when making these changes!

As you say, the "-quiet" and "-verbose" flags only effect the parser.
They should probably be renamed.

You are also right that the "-printsol" option never does anything.
Sorry about that.

The 'PRINT' statement and any command line flags are supposed to
forfill different roles. The 'PRINT' statement decides which variables
should be printed, as in many problems there are lots of variables
whose values we do not care about. This set cannot be changed from the
command line, the only choice which can be made is how things are
actually printed.

you might want to look at the "-tableout" option, which puts a number
of useful facts into another file, including size of search and time
taken. Then you could seperate reading the solutions and reading info
about search.

In terms of making Minion go faster however, there are some more
useful options available to you. You may have to experiment with
these:

1) See if you can tighten the bounds of the domains of the variables.
2) Look at the following options. Unfortunatly we can't give any hard
guidance on these, you just have to try them:

-preprocess does more work before search, to hopefully reduce the size
of search. It has 5 settings, which go in terms of increasing time.

GAC (the default), SACBounds, SAC, SSACBounds, SSAC.

Note that higher settings for these can take a LONG time, over an hour
for very large problems, and might not produce any gain!

-varorder is another powerful tool, but can be difficult to tune. Look
out for overtuning for one or two instances. Useful values to try are:

static (default) - goes in the order you list in the 'VARORDER' section.
conflict - which tries to search variables which have previously
caused problems.
sdf - Generally considered the "standard" order most people use.

One final option, which helps in some rare cases, is:

-X-prop-node SAC

Which runs a higher level of work at every node of search. This is
however rarely it.

(Note, the "-X" part means this flag may change, get renamed, or
disappear without notice!)

Chris