Due to lack of default search.

cf. chocoteam/choco-solver#117

Good day!

I've been testing the pulp integration done in issue #15 and while running pulp's internal tests we have arrived to a couple of bizarre results. For each result I'm sending the mps file of the test and the sol file I got. They're all very small examples.

Here I explain each of the cases:

• pulpTest009: choco returns optimal instead of infeasible
• pulpTest011: choco gives a non-optimal result while saying it's optimal.

Two of the cases are actually unbounded problems. Not sure how or if choco detects this and how it communicates it:

• pulpTest012: choco says optimal and returns a solution instead of unbounded.
• pulpTest123: choco crashes in a memory leak instead of saying it's unbounded.

thanks!

Franco
pulp_tests.zip

Good day!

I'm interested on integrating choco with python's PuLP library to test it with the models that I've modeled so far.
This library (PuLP) lets the user build one single model and then communicates with several linear programming solvers: CBC, GUROBI, CPLEX, XPRESS, glpk.

I guess there are multiple ways of doing the integration. One very simple way pulp communicates with some of these solvers is the following:

1. it creates a .mps or .lp file
2. it then calls the solver as a command line with the file as input,
3. the solver generates the output as a .sol file
4. PulP reads the output and converts it into the corresponding python variables.

I'm wondering if this could be done with choco. That is:

1. Is it possible to use choco as a command line application?
2. Is it possible for choco to read .mps or .lp files?

I'm aware that much of the functionality of the CP solver is lost sometimes doing these kinds of translations, specially if the models come from the LP / MIP world. Still I think it's useful to be able to at least test the solver for lazy people like me.

Of course, I'd be more than glad to edit the necessary parts in PuLP if needed (although I'm not the maintainer of the repo).

thanks!

Franco

1. the initial sort with ratio was bugged
2. the parser should rely on the choco-solver implementation

It would be interesting to have the option to write the solution into a file instead of only showing it in the screen. This could be configured by a new command line option like the following:

-o <file_path>

Also, although less important, would be to have the log output (progress) written into, yet another, file.

That way, we could at the same time show the output in screen and write it into a file and not mix the solution logging with the solution itself.

Thanks!

Franco

I think that the Master/Slave pattern describes in choco-parsers for multi-core resolution should be moved inside choco-solver.

In order to simplify the usage of the parser, there should be some entry points, kind of monitors, to provide an access to users to interact with parsed files.

In order to compile the project, I needed to change the version of the Java flavor in pom.xml from 1.7 to 1.8:

Indeed, in the file src/main/java/parser/flatzinc/Flatzinc.java, there is the following construction that requires Java 1.8:
ParserListener::afterParsingFile

I needed to change also in the file src/main/antlr4/parser/flatzinc/Flatzinc4Parser.g4:
import parser.flatzinc.FZNLayout;
into
import parser.flatzinc.layout.FZNLayout;

The way options are managed in the parser is not very flexible and should be revamped.
Something based on the configuration files would be a good idea.

<description>A Graphical User Interface to plug on Choco 3. </description>

The refactoring of the parsers removed default free search declaration.
It needs to be done for int and set vars.

Using the following program to solve a very easy instance of n-queens problem leads to an infinite solving time. This problem only occurs when we request to print all the solution (-a) found using an ActivityBased strategy (-bb 3).

public class demo {
  public static void main(String[] argv) throws Exception {
    org.chocosolver.parser.xcsp.XCSP xcsp = new org.chocosolver.parser.xcsp.XCSP();
    xcsp.addListener(new org.chocosolver.parser.xcsp.BaseXCSPListener(xcsp));
    xcsp.setUp(new String[]{"queens.xcsp3", "-a", "-bb", "3"});
    xcsp.defineSettings(new org.chocosolver.parser.xcsp.XCSPSettings());
    xcsp.createSolver();
    xcsp.buildModel();
    xcsp.configureSearch();
    xcsp.solve();
  }
}

queens.xcsp3:

<instance format="XCSP3" type="CSP">
<variables>
<array id="q" size="[4]"> 0..3 </array>
</variables>
<constraints>
<allDifferent>
q[]
</allDifferent>
<allDifferent>
add(q[0],0) add(q[1],1) add(q[2],2) add(q[3],3)
</allDifferent>
<allDifferent>
sub(q[0],0) sub(q[1],1) sub(q[2],2) sub(q[3],3)
</allDifferent>
</constraints>
</instance>

Hi choco team,

I want to know if there is a way to export my choco 4.5 model to XCSP3 format.

thank you in advance .

I am trying to export a Choco Model to JSON using Choco parsers. (Choco 4.0.6, Choco-parsers 4.0.4)

However, a dependency (xcsp3) in the pom.xml of choco-parsers cannot be resolved:

	<dependency>
		<groupId>org.choco-solver</groupId>
		<artifactId>choco-parsers</artifactId>
		<version>4.0.4</version>
	</dependency>

Description Resource Path Location Type
Missing artifact xcsp3:xcsp3:jar:1.0.1-SNAPSHOT pom.xml /SpringCaas line 3 Maven Dependency Problem

I checked the XCSP website, and did not find a direct match. Is there an easy workaround? Or where to find the xcsp3:xcsp3:jar:1.0.1-SNAPSHOT ?

Thank you!

• basic implementation of XCSP3 parser
• scripts
• implementing core constraints:
  • intension
    • arithmetical expressions
    • relational expressions
    • logical expressions
  • extension
  • regular
  • mdd
  • allDifferent
  • allEqual
  • ordered (and lex)
  • sum
  • count
  • cardinality
  • minimum
  • maximum
  • element
  • channel
  • stretch
  • noOverlap
  • cumulative
• extensive testing