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Open-source constraint solver.
/**
* Copyright (c) 2016, Ecole des Mines de Nantes
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the .
* 4. Neither the name of the nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.chocosolver.solver;
import org.chocosolver.memory.Except_0;
import org.chocosolver.memory.ICondition;
import org.chocosolver.solver.constraints.ISatFactory;
import org.chocosolver.solver.constraints.nary.automata.FA.ICostAutomaton;
import org.chocosolver.solver.search.strategy.Search;
import org.chocosolver.solver.search.strategy.strategy.AbstractStrategy;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.util.ESat;
/**
* Settings for {@link Model}.
* Since java8, acts as default settings.
*
* Created by cprudhom on 25/11/14.
* Project: choco.
* @author Charles Prud'homme
*/
public interface Settings {
/**
* List possible reaction to lack of propagator's idempotency.
*/
enum Idem {
/**
* Does nothing.
*/
disabled,
/**
* Prints an error message when a propagator is not guaranteed to be idempotent -- for debug only
*/
error,
/**
* Extra call to Propagator.propagate(FULL_PROPAGATION) when no more event is available
*/
force
}
/**
* @return the welcome message
*/
default String getWelcomeMessage() {
return "** Choco 4.0.1 (2016-12) : Constraint Programming Solver, Copyleft (c) 2010-2016";
}
/**
* Define how to react when a propagator is not ensured to be idempotent ({@link org.chocosolver.solver.Settings.Idem}).
*
* - disabled : does not anything
* - error: print an error message when a propagator is not guaranteed to be idempotent -- for debugging purpose only
* - force : extra call to Propagator.propagate(FULL_PROPAGATION) when no more event is available
*
* @return the idempotency strategy
*/
default Idem getIdempotencyStrategy() {
return Idem.disabled;
}
/**
* Define what to do when a solution is found.
* By default, it makes a weak check of the model:
*
* {@code
* return !ESat.FALSE.equals(solver.isSatisfied());
* }
*
* A hard check of the model can be done like this:
*
* {@code
* return ESat.TRUE.equals(solver.isSatisfied());
* }
*
* @param solver the solver
* @return true if the model is OK wrt the checker, false otherwise
*/
default boolean checkModel(Solver solver){
return !ESat.FALSE.equals(solver.isSatisfied());
}
/**
* Set to 'true' to allow the creation of views in the {@link org.chocosolver.solver.Model}.
* Creates new variables with channeling constraints otherwise.
* @return true if views are enabled.
*/
default boolean enableViews() {
return true;
}
/**
* Define the maximum domain size threshold to force integer variable to be enumerated
* instead of bounded while calling {@link org.chocosolver.solver.Model#intVar(String, int, int)}.
* @return maximum domain size threshold to force integer variable to be enumerated
*/
default int getMaxDomSizeForEnumerated() {
return 32768;
}
/**
* Set to true to replace some intension constraints by extension constraints
* @return true if some intension constraints can be replaced by extension constraints
*/
default boolean enableTableSubstitution() {
return true;
}
/**
* Define the maximum domain size threshold to replace intension constraints by extension constraints
* Only checked when ENABLE_TABLE_SUBS is set to true
* @return maximum domain size threshold to replace intension constraints by extension constraints
*/
default int getMaxTupleSizeForSubstitution() {
return 10000;
}
/**
* Defines the smallest used double for {@link org.chocosolver.solver.Model#multiCostRegular(IntVar[], IntVar[], ICostAutomaton)} algorithm
* @return the smallest used double for {@link org.chocosolver.solver.Model#multiCostRegular(IntVar[], IntVar[], ICostAutomaton)} algorithm
*/
default double getMCRDecimalPrecision() {
return 0.0001d;
}
/**
* Defines, for fine events, for each priority, the queue in which a propagator of such a priority should be scheduled in
* /!\ for advanced usage only
* @return the index of queue in which a propagator of a given priority should be scheduled in
*/
default short[] getFineEventPriority() {
return new short[]{0, 0, 0, 1, 2, 2, 2};
}
/**
* Defines, for coarse events, for each priority, the queue in which a propagator of such a priority should be scheduled in
* /!\ for advanced usage only
* @return the index of queue in which a propagator of a given priority should be scheduled in
*/
default short[] getCoarseEventPriority() {
return new short[]{0, 0, 0, 0, 1, 2, 3};
}
/**
* Indicates if propagators can be sorted wrt their priority in {@link org.chocosolver.solver.propagation.PropagationTrigger} when
* dealing with propagator activation. Set to true to allow sorting static propagators.
* false is the default value.
* @return whether or not propagators are sorted wrt their priority on initial activation.
*/
default boolean sortPropagatorActivationWRTPriority(){
return true;
}
/**
* Creates a default search strategy for the input model
*
* @param model a model requiring a default search strategy
* @return a default search strategy for model
* @see Search#defaultSearch(Model)
*/
default AbstractStrategy makeDefaultSearch(Model model) {
return Search.defaultSearch(model);
}
/**
* Return the condition to satisfy when rebuilding history of backtrackable objects is needed.
* Building "fake" history is needed when a backtrackable object is created during the search, in order to restore a correct state upon backtrack.
* The default condition is "at least one env.worldPush() has been called since the creation of the bck object".
* The condition can be set to {@link org.chocosolver.memory.ICondition#FALSE} if no backtrackable object is created during the search.
* @return the condition to satisfy when rebuilding history of backtrackable objects is needed.
*/
default ICondition getEnvironmentHistorySimulationCondition() {
return new Except_0();
}
/**
* Return true if one wants to be informed of warnings detected during modeling/solving (default value is false)
* @return true if warnings detected during modeling/solving are output.
*/
default boolean warnUser() {
return false;
}
/**
* When this setting returns true, a complete trace of the events is output.
* This can be quite big, though, and it slows down the overall process.
*
* Note that this parameter is read once at propagation engine creation and set in a final variable.
* Note that enabling colors may be helpful (see {@link #outputWithANSIColors()})
* @return true if all events are output in the console
*/
default boolean debugPropagation(){
return false;
}
/**
* Return true if boolean sum should be decomposed into an equality constraint and an arithmetic constraint,
* return false if a single constraint should be used instead.
* @return false
*/
default boolean enableDecompositionOfBooleanSum(){
return false;
}
/**
* Return true if the incrementality is enabled on boolean sum, based on the number of variables involved.
* Default condition is : nbvars > 10
* @param nbvars number of variables in the constraint
* @return true
*/
default boolean enableIncrementalityOnBoolSum(int nbvars) {
return nbvars > 1;
}
/**
* If your terminal support ANSI colors (Windows terminals don't), you can set this to true.
* @return enable output with colors
*/
default boolean outputWithANSIColors(){
return false;
}
/**
* If this setting is set to true (default value), a clone of the input variable array is made in any propagator constructors.
* This prevents, for instance, wrong behavior when permutations occurred on the input array (e.g., sorting variables).
* Setting this to false may limit the memory consumption during modelling.
* @return true if all propagators should clone the input variable array instead of simply referencing it.
*/
default boolean cloneVariableArrayInPropagator(){
return true;
}
/**
* If this is set to true then AC algorithm is used to filter ternary sum,
* otherwise, BC is used.
* Note AC brings more filtering when there are holes in variable domains but this comes at a cost.
* @return true if AC is enabled to filter ternary sums.
*/
default boolean enableACOnTernarySum(){
return false;
}
/**
* Define the prefix of internally created variables (through a call to {@link Model#generateName()}
* @return the prefix of all internally created variables
*/
default String defaultPrefix(){
return "TMP_";
}
/**
* @return true when an underlying SAT solver is used to manage clauses declared through {@link ISatFactory},
* false when clauses are managed with CSP constraints only.
*/
default boolean enableSAT(){
return false;
}
}