Solver path solvers "square" nonlinear complementarity problem;
it is based on the PATH solver of Professor Michael C. Ferris and
his (current or former) students Steven P. Dirkse and Todd S. Munson.

The makefile in this directory assumes that pathlib is a directory
of source for PATH (or at least that it contains a library built
from this source and the associated header files).  Contact
Professor Ferris (ferris@cs.wisc.edu) to see about getting the
pathlib directory.

Compilation with -DNEOS causes recognition of keywords "logfile",
"optfile", and "statusfile" in $path_options to be omitted.  With or
without -DNEOS, default values for these files may be specified with
-DLOGFILE='"logfile_name"', -DSTATUSFILE='"statusfile_name"', and
-DOPTFILE='"optfile_name"', respectively.  Absent such specifications,
or with 0 or NULL in place of a quoted string, the default is no such
file.


Papers related to PATH include

S. P. Dirkse, "Robust Solution of Mixed Complementarity Problems",
	Ph.D. thesis, Computer Sciences Dept., Univ. of Wisconsin,
	Madison, 1994.  Available from
	ftp://ftp.cs.wisc.edu/math-prog/tech-reports/.

Steven P. Dirkse and Michael C. Ferris, "The PATH Solver: A
	Non-Monotone Stabilization Scheme for Mixed Complementarity
	Problems", Optimization Methods and Software 5 (1995),
	pp. 123-156.

M. C. Ferris and T. S. Munson, "Interfaces to PATH 3.0: Design,
	Implementation and Usage", Math. Prog. Tech. Rep. 97-12,
	Univ. of Wisconsin, Madison, Computer Sciences Dept., 1997.
	Available from ftp://ftp.cs.wisc.edu/math-prog/tech-reports/.

Pointers to other relevant papers appear in
	http://www.cs.wisc.edu/~ferris/papers.html

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solve_result_num values
=======================

Here is a table of solve_result_num values that "path" can return
to an AMPL session, along with the text that appears in the associated
solve_message.

	Value	Message

	0	Solution found
	200	Inconsistent bounds
	201	Infeasible
	400	Major iteration limit
	401	Cumulative iteration limit
	402	Time limit
	403	User interrupt (such as control-C)
	500	Bug -- unexpected return code from PATH
	501	Solver error
	503	Domain error
	504	Nonsquare system (when "sqwarn" requires square)
	505	Problem has side inequalities (when "sideineq" allows none)
	510	Not enough progress

-----------------------

Questions about this stuff?  Contact dmg@ampl.com (David M. Gay).
