From 69b584afc537264a51afd423d05b7987f2f7312e Mon Sep 17 00:00:00 2001
From: Maxime MORGE <maxime.morge@univ-lille1.fr>
Date: Wed, 5 Feb 2020 17:07:13 +0100
Subject: [PATCH] Initial commit
---
.gitignore | 39 +
LICENSE | 674 ++++++++++++++++++
README.md | 60 +-
build.sbt | 20 +
.../scala/org/scadcop/actor/Directory.scala | 38 +
.../scala/org/scadcop/actor/Message.scala | 33 +
.../scala/org/scadcop/actor/SolverAgent.scala | 78 ++
.../org/scadcop/actor/VariableAgent.scala | 251 +++++++
src/main/scala/org/scadcop/dfs/DFS.scala | 60 ++
.../org/scadcop/problem/Constraint.scala | 63 ++
.../scala/org/scadcop/problem/Context.scala | 82 +++
src/main/scala/org/scadcop/problem/DCOP.scala | 44 ++
.../org/scadcop/problem/ToyExample.scala | 25 +
.../scala/org/scadcop/problem/Value.scala | 77 ++
.../scala/org/scadcop/problem/Variable.scala | 32 +
.../scadcop/solver/DistributedSolver.scala | 65 ++
.../scala/org/scadcop/solver/Solver.scala | 30 +
src/main/scala/org/scadcop/util/Main.scala | 31 +
.../scala/org/scadcop/util/MathUtils.scala | 15 +
19 files changed, 1716 insertions(+), 1 deletion(-)
create mode 100644 .gitignore
create mode 100644 LICENSE
create mode 100644 build.sbt
create mode 100644 src/main/scala/org/scadcop/actor/Directory.scala
create mode 100644 src/main/scala/org/scadcop/actor/Message.scala
create mode 100644 src/main/scala/org/scadcop/actor/SolverAgent.scala
create mode 100644 src/main/scala/org/scadcop/actor/VariableAgent.scala
create mode 100644 src/main/scala/org/scadcop/dfs/DFS.scala
create mode 100644 src/main/scala/org/scadcop/problem/Constraint.scala
create mode 100644 src/main/scala/org/scadcop/problem/Context.scala
create mode 100644 src/main/scala/org/scadcop/problem/DCOP.scala
create mode 100644 src/main/scala/org/scadcop/problem/ToyExample.scala
create mode 100644 src/main/scala/org/scadcop/problem/Value.scala
create mode 100644 src/main/scala/org/scadcop/problem/Variable.scala
create mode 100644 src/main/scala/org/scadcop/solver/DistributedSolver.scala
create mode 100644 src/main/scala/org/scadcop/solver/Solver.scala
create mode 100644 src/main/scala/org/scadcop/util/Main.scala
create mode 100644 src/main/scala/org/scadcop/util/MathUtils.scala
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..469d4f7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,39 @@
+### OSX ###
+*.DS_Store
+
+### SBT ###
+target/
+lib_managed/
+src_managed/
+project/boot/
+.history
+.cache
+
+# sbt specific
+.lib/
+dist/*
+project/plugins/project/
+
+### Scala ###
+*.class
+*.log
+
+### Emacs ###
+\#*\#
+
+### Intellij ###
+.idea/
+*.iml
+.cache-main
+
+### VS ###
+.metals/
+.vscode/
+.bloop
+project/.bloop
+
+## Misc ###
+project/build.properties
+project/project/
+experiments/figures/
+
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..f288702
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,674 @@
+ GNU GENERAL PUBLIC LICENSE
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+ Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+ 12. No Surrender of Others' Freedom.
+
+ If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License. If you cannot convey a
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+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+ 13. Use with the GNU Affero General Public License.
+
+ Notwithstanding any other provision of this License, you have
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+combination as such.
+
+ 14. Revised Versions of this License.
+
+ The Free Software Foundation may publish revised and/or new versions of
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+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+ Each version is given a distinguishing version number. If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation. If the Program does not specify a version number of the
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+
+ If the Program specifies that a proxy can decide which future
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+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+ Later license versions may give you additional or different
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+
+ 15. Disclaimer of Warranty.
+
+ THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
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+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
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+ 16. Limitation of Liability.
+
+ IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
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+SUCH DAMAGES.
+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
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+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+ <one line to give the program's name and a brief idea of what it does.>
+ Copyright (C) <year> <name of author>
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
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+ If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+ <program> Copyright (C) <year> <name of author>
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+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+ You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+ The GNU General Public License does not permit incorporating your program
+into proprietary programs. If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License. But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/README.md b/README.md
index 328c48e..5e3da75 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,61 @@
# ScaDCOP
+ScaDCOP is a Scala library of algorithm for Distributed Constraints Optimization Problems
-ScaDOPT is a Scala library of algorithm for Distributed Constraints Optimization Problems
\ No newline at end of file
+## What is ScaDCOP ?
+
+ScaDCOP is a Scala library of algorithm for Distributed Constraints
+Optimization Problems. We have implemented our prototype with the
+[Scala](https://www.scala-lang.org/) programming language and the
+[Akka](http://akka.io/) toolkit. The latter, which is based on the
+actor model, allows us to fill the gap between the specification and
+its implementation.
+
+
+## Requirements
+
+In order to run the demonstration you need:
+
+- the Java virtual machine [JVM 1.8.0_60](http://www.oracle.com/technetwork/java/javase/downloads/index.html).
+
+In order to compile the code you need:
+
+- the programming language [Scala 2.12.4](http://www.scala-lang.org/download/);
+
+- the interactive build tool [SBT 1.2.1](http://www.scala-sbt.org/download.html).
+
+## Usage
+
+ java -jar scadcop-assembly-X.Y.jar
+
+
+## Installation
+
+Compile
+
+ sbt compile
+
+then
+
+ sbt "run org.ALGO.util.Main"
+
+and eventually
+
+ sbt assembly
+
+
+## Contributors
+
+Copyright (C) Maxime MORGE 2020
+
+## License
+
+This program is free software: you can redistribute it and/or modify it under the terms of the
+GNU General Public License as published by the Free Software Foundation, either version 3 of the License,
+or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with this program.
+If not, see <http://www.gnu.org/licenses/>.
diff --git a/build.sbt b/build.sbt
new file mode 100644
index 0000000..10ffe5a
--- /dev/null
+++ b/build.sbt
@@ -0,0 +1,20 @@
+name := "ScaDCOP"
+
+version := "0.1"
+
+mainClass in (Compile,run) := Some("org.scadcop.util.Main")
+mainClass in assembly := Some("org.scadcop.util.Main")
+
+trapExit := false
+
+resolvers += "Artifactory-UCL" at "http://artifactory.info.ucl.ac.be/artifactory/libs-snapshot-local/"
+resolvers += "Typesafe Repository" at "http://repo.typesafe.com/typesafe/releases/"
+
+scalaVersion := "2.12.4"
+
+libraryDependencies ++= Seq(
+ "com.typesafe.akka" %% "akka-actor" % "2.5.20",
+ "com.typesafe.akka" %% "akka-remote" % "2.5.20"
+)
+
+
diff --git a/src/main/scala/org/scadcop/actor/Directory.scala b/src/main/scala/org/scadcop/actor/Directory.scala
new file mode 100644
index 0000000..74c7fae
--- /dev/null
+++ b/src/main/scala/org/scadcop/actor/Directory.scala
@@ -0,0 +1,38 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.actor
+
+import akka.actor.ActorRef
+import org.scadcop.problem.Variable
+
+/**
+ * Class representing an index of the names and addresses of peers
+ */
+class Directory {
+ var adr : Map[Variable, ActorRef] = Map[Variable, ActorRef]()//Variables' actors
+ var variables : Map[ActorRef, Variable] = Map[ActorRef, Variable]()// Actors' variable
+
+ /**
+ * String representation
+ */
+ override def toString: String = allVariables().mkString("[",", ","]")
+
+ /**
+ * Add to the directory
+ * @param variable to add
+ * @param ref to add
+ */
+ def add(variable: Variable, ref: ActorRef) : Unit = {
+ if ( ! adr.keySet.contains(variable) && ! variables.keySet.contains(ref)) {
+ adr += (variable -> ref)
+ variables += (ref -> variable)
+ }
+ else throw new RuntimeException(s"$variable and/or $ref already in the directory")
+ }
+
+ def allActors() : Iterable[ActorRef] = adr.values
+ def allVariables() : Iterable[Variable] = variables.values
+ def peers(variable: Variable) : Set[Variable] = allVariables().filterNot(_ ==variable).toSet
+ def peersActor(variable: Variable) : Iterable[ActorRef] = peers(variable: Variable).map(w => adr(w))
+
+}
+
diff --git a/src/main/scala/org/scadcop/actor/Message.scala b/src/main/scala/org/scadcop/actor/Message.scala
new file mode 100644
index 0000000..81f13a9
--- /dev/null
+++ b/src/main/scala/org/scadcop/actor/Message.scala
@@ -0,0 +1,33 @@
+// Copyright (C) Maxime MORGE 2019
+package org.scadcop.actor
+
+import org.scadcop.problem.{Context, Variable, Value}
+
+/**
+ * All possible messages between the actors
+ */
+abstract class Message
+
+// Managing messages
+// Debuging message
+case object Trace extends Message
+// Starts the solving
+case object Start extends Message
+// Initiates a variable agent with a directory, children, and eventually a parent
+case class Init(directory : Directory, parent : Option[Variable], children: Set[Variable]) extends Message
+// The variable agent is ready to start
+case object Ready extends Message
+// Gives an assignment and the statistics
+case class Outcome(assignment : Context) extends Message
+// Stops an agent
+case object Stop extends Message
+
+// DCOP messages
+// Fixes the value of the variable agent
+case class Assign(value : Value) extends Message
+// Generalizes the nogood message of DisCSP
+case class Cost(lb : Double, ub: Double, ctxt : Context) extends Message
+// Reduces the redundant search
+case class Threshold(threshold: Double, ctxt : Context) extends Message
+// Terminates the children with a context
+case class Terminate(ctxt: Context) extends Message
\ No newline at end of file
diff --git a/src/main/scala/org/scadcop/actor/SolverAgent.scala b/src/main/scala/org/scadcop/actor/SolverAgent.scala
new file mode 100644
index 0000000..ae89725
--- /dev/null
+++ b/src/main/scala/org/scadcop/actor/SolverAgent.scala
@@ -0,0 +1,78 @@
+// Copyright (C) Maxime MORGE 2019
+package org.scadcop.actor
+
+import org.scadcop.problem.{Context, DCOP, Variable}
+import org.scadcop.dfs.DFS
+
+import akka.actor.{Actor, ActorRef, Props}
+
+/**
+ * SolverAgent which starts and stops the computation of an assignment
+ * @param pb DCOP instance
+ * */
+class SolverAgent(val pb: DCOP) extends Actor{
+ var debug = true
+ // The actor which triggers the simulation and gathers the steps
+ private var solver : ActorRef= context.parent
+ // Number of agents which are ready
+ private var nbReady = 0
+ // Is the solver agent started
+ var started = false
+ // White page variable/actor
+ private val directory = new Directory()
+ // The assignment to build
+ private val assignment = new Context(pb)
+
+ // Deploy and init
+ pb.variables.foreach{ variable =>
+ val actor = context.actorOf(Props(classOf[VariableAgent], variable, pb), variable.id.toString)
+ directory.add(variable, actor) // Add it to the directory
+ }
+ init(DFS(pb), None)
+
+ /**
+ * Returns the root variable of the DFS whose children have been initiated
+ */
+ def init(dfs: DFS, parent: Option[Variable]) : Variable = {
+ var neighbors = Set[Variable]()
+ dfs.children.foreach{ subDfs =>
+ neighbors += init(subDfs,Some(dfs.root))
+ }
+ directory.adr(dfs.root) ! Init(directory, parent, neighbors)
+ dfs.root
+ }
+
+ /**
+ * Message handling
+ */
+ override def receive: Receive = {
+ // When a variable agent is ready
+ case Ready =>
+ nbReady += 1
+ if (nbReady == pb.variables.size && started) directory.allActors().foreach(_ ! Start)
+
+ //When debugging mode is triggered
+ case Trace =>
+ debug = true
+ directory.allActors().foreach(_ ! Trace)
+
+ //When the solving is triggered
+ case Start =>
+ solver = sender
+ started = true
+ if (nbReady == pb.variables.size ) directory.allActors().foreach(_ ! Start)
+
+ //When the value of variable is setup
+ case Assign(value) =>
+ assignment.valuation += (directory.variables(sender) -> value)
+ if (assignment.isAssignment){
+ solver ! Outcome(assignment) // reports the allocation
+ context.stop(self) //stops the solverAgent
+ }
+
+ // Unexpected message
+ case msg@_ =>
+ println("WARNING: SolverAgent receives a message which was not expected: " + msg)
+ }
+
+}
diff --git a/src/main/scala/org/scadcop/actor/VariableAgent.scala b/src/main/scala/org/scadcop/actor/VariableAgent.scala
new file mode 100644
index 0000000..7b2fba2
--- /dev/null
+++ b/src/main/scala/org/scadcop/actor/VariableAgent.scala
@@ -0,0 +1,251 @@
+// Copyright (C) Maxime MORGE 2019
+package org.scadcop.actor
+
+import org.scadcop.problem.{Context, DCOP, Value, Variable}
+import org.scadcop.util.MathUtils.MathUtils
+
+import akka.actor.{Actor, ActorRef}
+
+/**
+ * SolverAgent which starts and stops the computation of an allocation
+ * @param variable which should be valuated
+ * @param pb DCOP instance
+ * */
+
+class VariableAgent(variable : Variable, pb : DCOP) extends Actor {
+ var debug = true
+ var trace = true
+ // The actor which triggers the resolution
+ private var solverAgent : ActorRef= context.parent
+ // White page variable/actor
+ private var directory = new Directory()
+ // parent variable in the DFS
+ private var parent : Option[Variable] = None
+ // Children variables in the DFS
+ private var children = Set[Variable]()
+ // Agent's view of the assignment of higher neighbors
+ private var currentContext : Context = new Context(pb)
+ // lower bound for the different couples (value,child)
+ private var lb = Map[(Value,Variable),Double]()
+ // upper bound for the different couples (value,child)
+ private var ub = Map[(Value,Variable),Double]()
+ // The backtrack threshold for the different couples (value,child)
+ private var t = Map[(Value,Variable),Double]()
+ private var threshold : Double = 0.0
+ // Current value of the variable
+ private var di : Value = variable.domain.head
+ // True if the agent has received a terminate message from the parent
+ private var terminated : Boolean = false
+
+ /**
+ * Returns true if the agent is a leaf agent
+ */
+ def isLeafAgent: Boolean = children.isEmpty
+
+ /**
+ * Returns true if the agent is a root agent
+ */
+ def isRootAgent: Boolean = parent.isEmpty
+
+ /**
+ * Returns the lower level neighbors
+ */
+ def neighbors() : Set[ActorRef] = children.map(v => directory.adr(v))
+
+ /**
+ * Returns the value which minimizes a bound
+ */
+ def minimize(bound : Value=> Double) : Value = {
+ var dj = variable.domain.head
+ var min = Double.MaxValue
+ variable.domain.foreach { d =>
+ if (bound(d) < min) {
+ dj = d
+ min = bound(d)
+ }
+ }
+ dj
+ }
+
+ /**
+ * Resets bounds
+ */
+ def resetBound() : Unit ={
+ //If the agent is not a leaf but has not yet received any COST messages from its children,
+ // UB is equal to maximum value Inf and LB is equal to the minimum local cost δ(d) over all value choices d ∈ Di .
+ variable.domain.foreach{ v: Value =>
+ children.foreach{ child : Variable =>
+ lb += ((v, child) -> 0.0)
+ ub += ((v, child) -> Double.MaxValue)
+ t += ((v, child) -> 0.0)
+ }
+ }
+ }
+
+ /**
+ * Returns the local cost for a specific value
+ */
+ def ∂(value: Value) : Double = {
+ var cost = 0.0
+ currentContext.valuation.keys.filter(_ == variable).foreach { otherVariable =>
+ pb.constraints.foreach { c =>
+ if (c.isOver(variable) && c.isOver(otherVariable)) {
+ val cc = c.cost(variable, currentContext.valuation(variable), otherVariable, currentContext.valuation(otherVariable))
+ cost += cc
+ }
+ }
+ }
+ cost
+ }
+
+ /**
+ * Returns the lower bound for the subtree rooted at the variable
+ * when the variable chooses value
+ */
+ def LB(value: Value) : Double = {
+ ∂(value) + (if (! isLeafAgent) children.toSeq.map(v => lb(value,v) ).sum else 0.0)
+ }
+
+ /**
+ * Returns the upper bound for the subtree rooted at the variable
+ * when the variable chooses value
+ */
+ def UB(value: Value) : Double = {
+ ∂(value) + (if (! isLeafAgent) children.toSeq.map(v => ub(value,v) ).sum else 0.0)
+ }
+
+ /**
+ * Returns a lower bound for the subtree rooted at the variable
+ */
+ def LB : Double = variable.domain.map(v => LB(v)).min
+
+ /**
+ * Returns a upper bound for the subtree rooted at the variable
+ */
+ def UB : Double = variable.domain.map(v => UB(v)).min
+
+ // A leaf agent has no subtree so δ(d) = LB(d) = UB(d) for all value choices d and thus,
+ // LB is always equal to UB at a leaf.
+
+ /**
+ * Message handling
+ */
+ override def receive: Receive = {
+ // When the variable agent is initiated
+ case Init(d, p, c) =>
+ solverAgent = sender
+ directory = d
+ parent = p
+ children = c
+ initialize()
+
+ // When the parent terminate
+ case Terminate(ctxt) =>
+ terminated = true
+ currentContext = ctxt
+ backtrack()
+
+ // When the parent agent sets the threshold value
+ case Threshold(thresholdValue,ctxt) =>
+ if (ctxt.isCompatible(currentContext)){
+ threshold = thresholdValue
+ maintainThresholdInvariant()
+ backtrack()
+ }
+
+ //
+ case Cost(lb, ub, ctxt) =>
+ //TODO
+
+ // When debugging mode is triggered
+ case Trace =>
+ trace = true
+
+ // Unexpected message
+ case msg@_ =>
+ println(s"WARNING: VariableAgent $variable receives a message from ${directory.variables(sender)} which was not expected: " + msg)
+ }
+
+
+ /**
+ * Initialize procedure
+ */
+ def initialize() : Unit = {
+ if (debug) println(s"Agent $variable initializes")
+ threshold = 0.0
+ currentContext.fix(Map())
+ resetBound()// initiate lb/up
+ di = minimize(LB)// di ↠d that minimizes LB(d)
+ //solverAgent ! Assign(di)
+ backtrack()
+ }
+
+ /**
+ * Backtrack procedure
+ */
+ def backtrack() : Unit = {
+ if (debug) println(s"Agent $variable backtracks")
+ if (threshold ~= UB) {
+ di = minimize(UB)// di ↠d that minimizes UB(d)
+ }else if(LB(di) > threshold){
+ di = minimize(LB)// di ↠d that minimizes LB(d)
+ }
+ // Sends value to each lower priority neighbor;
+ neighbors().foreach{ neighbor =>
+ if (trace) println(s"$variable -> ${directory.variables(neighbor)} : Assign($di)")
+ neighbor ! Assign(di)
+ }
+ maintainAllocationInvariant()
+ if (threshold ~= UB){
+ if (terminated || isRootAgent) {
+ currentContext.fix(variable,di)
+ neighbors().foreach{ neighbor =>
+ if (trace) println(s"$variable -> ${directory.variables(neighbor)} : Terminate($currentContext)")
+ neighbor ! Terminate(currentContext)
+ }
+ solverAgent ! Assign(di)
+ context.stop(self)
+ }
+ }
+ // Sends Cost to parent
+ currentContext.fix(variable,di)
+ if (parent.isDefined){
+ if (trace) println(s"$variable -> ${parent.get} : Cost($LB, $UB, $currentContext) ")
+ directory.adr(parent.get) ! Cost(LB, UB, currentContext)
+ }
+ }
+
+ /**
+ * Maintains allocation invariant
+ */
+ def maintainAllocationInvariant() : Unit = {
+ if (debug) println(s"Agent $variable maintains allocation invariant")
+ //we assume thresholdInvariant is satisfied
+ maintainThresholdInvariant()
+ while (threshold > ∂(di) + children.toSeq.map(xl => t(di, xl)).sum) {
+ //choose xl ∈Children where ub(di,xl)>t(di,xl);
+ val xl = children.find(xl => ub(di, xl) > t(di, xl))
+ if (xl.isDefined) t += ((di, xl.get) -> (t(di, xl.get) + 1.00))
+ }
+ while (threshold < ∂(di) + children.toSeq.map(xl => t(di, xl)).sum) {
+ //choose xl ∈Children where t(di,xl)>lb(di,xl);
+ val xl = children.find(xl => t(di, xl) > lb(di, xl))
+ if (xl.isDefined) t += ((di, xl.get) -> (t(di, xl.get) - 1.00))
+ }
+ currentContext.fix(variable,di)
+ children.foreach{ xl =>
+ if (trace) println(s"$variable -> $xl : Threshold(${t(di ,xl)}, $currentContext)")
+ directory.adr(xl) ! Threshold(t(di ,xl), currentContext)
+ }
+ }
+
+ /**
+ * Maintains threshold invariant
+ */
+ def maintainThresholdInvariant() : Unit = {
+ if (debug) println(s"Agent $variable maintains threshold invariant")
+ if (threshold < LB) threshold = LB
+ if (threshold > UB) threshold = UB
+ }
+
+}
diff --git a/src/main/scala/org/scadcop/dfs/DFS.scala b/src/main/scala/org/scadcop/dfs/DFS.scala
new file mode 100644
index 0000000..47c4d76
--- /dev/null
+++ b/src/main/scala/org/scadcop/dfs/DFS.scala
@@ -0,0 +1,60 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.dfs
+
+import org.scadcop.problem.{DCOP,Variable}
+
+/**
+ * Class representing a depth-first search tree for a DCOP
+ * @param root variable
+ */
+class DFS(val root : Variable){
+ var children : Set[DFS] = Set[DFS]()
+
+ /**
+ * String representation
+ */
+ override def toString: String = {
+ root.id + children.mkString("[",",","]")
+ }
+}
+
+
+/**
+ * Factory for [[org.scadcop.dfs.DFS]] instances
+ */
+object DFS{
+ // Is the variables are marked
+ var marked : Map[Variable,Boolean] = Map[Variable,Boolean]()
+
+ /**
+ * Factory's method
+ * @param pb DCOP
+ */
+ def apply(pb: DCOP): DFS = {
+ apply(pb,pb.variables.head)
+ }
+
+ /**
+ * Factory's method
+ * @param pb DCOP
+ * @param root variable
+ */
+ def apply(pb: DCOP, root: Variable): DFS = {
+ pb.variables.foreach { v =>
+ marked += (v -> false)
+ }
+ buildDFS(pb, root)
+ }
+
+ /**
+ * Returns a DFS which is recursively built
+ */
+ def buildDFS(pb: DCOP, root : Variable): DFS = {
+ val dfs = new DFS(root)
+ marked += (root -> true)
+ pb.linked(root).foreach{ v => // for each linked variable
+ if (! marked(v)) dfs.children += buildDFS(pb, v) // if the variable is not marked add subtree
+ }
+ dfs
+ }
+}
\ No newline at end of file
diff --git a/src/main/scala/org/scadcop/problem/Constraint.scala b/src/main/scala/org/scadcop/problem/Constraint.scala
new file mode 100644
index 0000000..5d24393
--- /dev/null
+++ b/src/main/scala/org/scadcop/problem/Constraint.scala
@@ -0,0 +1,63 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.problem
+
+/**
+ * Class representing a binary constraint over two variables
+ * which valuates the cost of each couple of values
+ * @param variable1 the first variable
+ * @param variable2 the second variable
+ * @param cost the cost matrix
+ */
+class Constraint(val variable1: Variable, val variable2: Variable, val cost : Array[Array[Double]]){
+
+ /**
+ * String representation
+ */
+ override def toString: String = {
+ var r = s"Cost(x${variable1.id})(x${variable2.id})\n"
+ for {
+ i <- variable1.domain.indices
+ j <- variable2.domain.indices
+ } r+=s"\t\tCost($i)($j) = ${cost(i)(j)}\n"
+ r
+ }
+
+ /**
+ * Returns true if the constraint is sound, i.e
+ * the cost of each couple of values is known and positive
+ */
+ def sound() : Boolean = {
+ if (this.cost.length != variable1.domain.size) return false
+ for {
+ i <- variable1.domain.indices
+ } if (this.cost(i).length != variable1.domain.size) return false
+ for {
+ i <- variable1.domain.indices
+ j <- variable2.domain.indices
+ } if (cost(i)(j) < 0.0) return false
+ true
+ }
+
+ /**
+ * Returns true if the constraint is over a specific variable
+ */
+ def isOver(variable: Variable) : Boolean = variable == variable1 || variable == variable2
+
+ /**
+ * Returns the cost when
+ * variableA is assigned to valueA
+ * and variableB is assigned to valueB
+ */
+ def cost(variableA: Variable, valueA: Value, variableB: Variable, valueB: Value) : Double = {
+ var (index1,index2) = (0,0)
+ if (variableA == variable1) {
+ index1 = variable1.index(valueA)
+ index2 = variable2.index(valueB)
+ } else if (variableA == variable2) {
+ index2 = variable1.index(valueA)
+ index1 = variable2.index(valueB)
+ } else throw new RuntimeException(s"Constraint $this is not about $variableA and $variableB")
+ cost(index1)(index2)
+ }
+
+}
diff --git a/src/main/scala/org/scadcop/problem/Context.scala b/src/main/scala/org/scadcop/problem/Context.scala
new file mode 100644
index 0000000..e19d248
--- /dev/null
+++ b/src/main/scala/org/scadcop/problem/Context.scala
@@ -0,0 +1,82 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.problem
+
+/**
+ * Class representing a full assignment or a partial context
+ * Each variable agent maintains a record of higher priority neighbors
+ * @param pb DCOP instance
+ * @param valuation for each variable
+ */
+class Context(val pb : DCOP, var valuation : Map[Variable, Value]){
+
+ /**
+ * Secondary constructor
+ */
+ def this(pb : DCOP) = {
+ this(pb, Map[Variable, Value]())
+ }
+
+ /**
+ * Fix the value of a variable in the context
+ */
+ def fix(variable : Variable, value: Value) : Unit ={
+ if (! variable.domain.contains(value))
+ throw new RuntimeException(s"$variable=$value is forbidden since $value is not in ${variable.domain}")
+ valuation += (variable -> value)
+ }
+
+ /**
+ * Fix the values of variables in the context
+ */
+ def fix(values : Map[Variable, Value]) : Unit ={
+ values.foreach{ case (variable, value) =>
+ fix(variable,value)
+ }
+ }
+
+ /**
+ * Remove a variable in the context
+ */
+ def remove(variable: Variable) : Unit = {
+
+ }
+
+ /**
+ * Returns true if the context is compatible with ctxt, i.e.
+ * they do not disagree on any variable assignment
+ */
+ def isCompatible(ctxt : Context) : Boolean =
+ this.valuation.keys.toSet.intersect(ctxt.valuation.keys.toSet).forall( variable => this.valuation(variable) == ctxt.valuation(variable))
+
+ /**
+ * Returns the objective value of the assignment
+ */
+ def objective() : Double = {
+ var sum = 0.0
+ pb.constraints.foreach{ c =>
+ sum += c.cost(c.variable1, valuation(c.variable1), c.variable2, valuation(c.variable2))
+ }
+ sum
+ }
+
+ /**
+ * Returns true if the pb is sound,
+ * i.e. each value is in the corresponding domain
+ */
+ def sound() : Boolean = {
+ pb.variables.foreach{ variable =>
+ if (! variable.domain.contains(valuation(variable))) return false
+ }
+ true
+ }
+
+ /**
+ * Returns true if the assignment is full
+ */
+ def isAssignment: Boolean = valuation.size == pb.variables.size
+
+ /**
+ * String representation of the assignment
+ */
+ override def toString: String = valuation.mkString("[",", ","]")
+}
diff --git a/src/main/scala/org/scadcop/problem/DCOP.scala b/src/main/scala/org/scadcop/problem/DCOP.scala
new file mode 100644
index 0000000..31c9687
--- /dev/null
+++ b/src/main/scala/org/scadcop/problem/DCOP.scala
@@ -0,0 +1,44 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.problem
+
+/**
+ * Class representing a Distributed Constraint Optimization Problem
+ * @param variables for which values must be given
+ * @param constraints represented as cost functions
+ */
+class DCOP(val variables: Set[Variable], val constraints : List[Constraint]){
+
+ /**
+ * String representation
+ */
+ override def toString: String = s"Variables:\n"+
+ variables.map(v => v.description).mkString("\t", "\n\t", "\n")+
+ "Constraints:\n"+
+ constraints.mkString("\t", "\n\t", "\n")
+
+ /**
+ * Returns the variables linked to v
+ */
+ def linked(v : Variable) : List[Variable] = {
+ var l = List[Variable]()
+ constraints.foreach{ c =>
+ if (c.variable1 == v) l = c.variable2 :: l
+ if (c.variable2 == v) l = c.variable1 :: l
+ }
+ l
+ }
+
+ /**
+ * Returns true if the DCOP is sound, i.e.
+ * 1 -there is at least one variable,
+ * 2- each variable has a unique id
+ * all the constraints are sound
+ */
+ def sound() : Boolean = variables.nonEmpty && variables.map(_.id).size == variables.size && constraints.forall( c => c.sound())
+
+ /**
+ * Returns the constraints over a specific variable
+ */
+ def constraints(variable: Variable) : List[Constraint] = constraints.filter(c => c.variable1 != variable && c.variable2 != variable)
+}
+
diff --git a/src/main/scala/org/scadcop/problem/ToyExample.scala b/src/main/scala/org/scadcop/problem/ToyExample.scala
new file mode 100644
index 0000000..6f88447
--- /dev/null
+++ b/src/main/scala/org/scadcop/problem/ToyExample.scala
@@ -0,0 +1,25 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.problem
+
+/**
+ * Object representing a toy DCOP instance
+ */
+object ToyExample {
+ val t = BooleanValue(false)
+ val f = BooleanValue(true)
+ val booleanDomain = List(t, f)
+ val x1 = new Variable(id = 1, booleanDomain)
+ val x2 = new Variable(id = 2, booleanDomain)
+ val x3 = new Variable(id = 3, booleanDomain)
+ val x4 = new Variable(id = 4, booleanDomain)
+ val cost = Array(Array(1.0, 2.0), Array(2.0, 0.0))
+ val c12 = new Constraint(x1, x2, cost)
+ val c13 = new Constraint(x1, x3, cost)
+ val c23 = new Constraint(x2, x3, cost)
+ val c24 = new Constraint(x2, x4, cost)
+ val pb = new DCOP(Set(x1, x2, x3, x4), List(c24, c23, c13, c12))
+ val a1 = new Context(pb)
+ a1.fix(Map(x1-> t, x2 -> t, x3 -> t, x4 -> t))
+ val a2 = new Context(pb)
+ a2.fix(Map(x1 -> f, x2 -> f, x3 -> f, x4 -> f))
+}
diff --git a/src/main/scala/org/scadcop/problem/Value.scala b/src/main/scala/org/scadcop/problem/Value.scala
new file mode 100644
index 0000000..ba20ade
--- /dev/null
+++ b/src/main/scala/org/scadcop/problem/Value.scala
@@ -0,0 +1,77 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.problem
+
+/**
+ * A domain for a variable is an ordered list of values
+ */
+package object domain {
+ type Domain = List[Value]
+}
+
+/**
+ * Abstract class for representing values of variables.
+ */
+abstract class Value{
+ /**
+ * Returns true if this value is equal to v
+ */
+ def equal(v: Value): Boolean
+
+ /**
+ * Returns a string representation of the value
+ */
+ override def toString: String
+}
+
+/**
+ * Class for representing values of nominal variables, i.e.
+ * variables whose domains are finite
+ */
+case class NominalValue(value : String) extends Value{
+ /**
+ * A secondary constructor.
+ */
+ def this(intVal: Int) {
+ this(intVal.toString)
+ }
+
+ /**
+ * Returns true if this value is equal to v
+ */
+ def equal(v: Value) : Boolean = {
+ v match {
+ case v : NominalValue => value == v.value
+ case _ => false
+ }
+ }
+
+ /**
+ * Returns a string representation of the value
+ */
+ override def toString: String = value
+}
+
+/**
+ * Class for representing values of a boolean variable, i.e.
+ * variables whose values are true and false
+ */
+case class BooleanValue(value : Boolean) extends Value{
+
+ /**
+ * Returns true if this value is equal to v
+ */
+ def equal(v: Value) : Boolean = {
+ v match {
+ case v : BooleanValue => value == v.value
+ case _ => false
+ }
+ }
+
+ /**
+ * Returns a string representation of the value
+ */
+ override def toString: String = {
+ if (value) return "True"
+ "False"
+ }
+}
\ No newline at end of file
diff --git a/src/main/scala/org/scadcop/problem/Variable.scala b/src/main/scala/org/scadcop/problem/Variable.scala
new file mode 100644
index 0000000..f7124e0
--- /dev/null
+++ b/src/main/scala/org/scadcop/problem/Variable.scala
@@ -0,0 +1,32 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.problem
+
+import domain.Domain
+
+/**
+ * Class representing a variable
+ * @param id is the id of the variable
+ * @param domain is a finite and and discrete set of values
+ */
+class Variable(val id: Int, val domain: Domain){
+ /**
+ * Long string representation of the variable
+ */
+ def description : String = s"x$id in "+domain.mkString("[", ", ", "]")
+
+ /**
+ * Short string representation of the variable
+ */
+ override def toString : String = s"x$id"
+
+ /**
+ * Returns the index of a specific value
+ */
+ def index(value : Value) : Int = domain.indexOf(value)
+
+ /**
+ * Return true if the variable is sound, i.e. a non-empty domain
+ */
+ def sound() : Boolean = domain.nonEmpty
+}
+
diff --git a/src/main/scala/org/scadcop/solver/DistributedSolver.scala b/src/main/scala/org/scadcop/solver/DistributedSolver.scala
new file mode 100644
index 0000000..392a414
--- /dev/null
+++ b/src/main/scala/org/scadcop/solver/DistributedSolver.scala
@@ -0,0 +1,65 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.solver
+
+import org.scadcop.problem.{DCOP,Context}
+import org.scadcop.actor.{SolverAgent,Trace,Outcome,Start}
+
+import akka.actor.{ActorRef, ActorSystem, Props}
+import akka.pattern.ask
+import akka.util.Timeout
+import scala.concurrent.Await
+import scala.concurrent.duration._
+import scala.language.postfixOps
+
+
+/**
+ * Distributed solver based on multi-agent negotiation process of single gift in order to minimize the rule
+ * @param pb to be solver
+ * @param system of Actors
+ */
+class DistributedSolver(pb : DCOP, system: ActorSystem) extends Solver(pb) {
+
+ val TIMEOUTVALUE : FiniteDuration = 6000 minutes // Default timeout of a run
+ implicit val timeout : Timeout = Timeout(TIMEOUTVALUE)
+ // Launch a new solverAgent
+ DistributedSolver.id+=1
+ val supervisor : ActorRef = system.actorOf(Props(classOf[SolverAgent], pb), name = "solverAgent"+DistributedSolver.id)
+
+ //TODO nb messages
+
+ /**
+ * Returns an allocation
+ */
+ override def solve(): Context = {
+ if (debug) println("@startuml")
+ if (debug) println("skinparam monochrome true")
+ if (debug) println("hide footbox")
+ if (debug) {
+ for (i<- 1 to pb.variables.size) println(s"participant $i")
+ }
+ if (debug) supervisor ! Trace
+ val future = supervisor ? Start
+ val result = Await.result(future, timeout.duration).asInstanceOf[Outcome]
+ if (debug) println("@enduml")
+ //TODO count message
+ result.assignment
+ }
+}
+
+object DistributedSolver{
+ var id = 0
+ val debug = false
+ def main(args: Array[String]): Unit = {
+ import org.scadcop.problem.ToyExample._
+ println(pb)
+ val r = scala.util.Random
+ val system = ActorSystem("DistributedSolver" + r.nextInt.toString)
+ //The Actor system
+ val adoptSolver = new DistributedSolver(pb, system)// SingleGiftOnly SingleSwapAndSingleGift
+ adoptSolver.debug = true
+ val sol = adoptSolver.solve()
+ println(sol.toString)
+ println("Objective "+sol.objective())
+ System.exit(1)
+ }
+}
diff --git a/src/main/scala/org/scadcop/solver/Solver.scala b/src/main/scala/org/scadcop/solver/Solver.scala
new file mode 100644
index 0000000..30c57cf
--- /dev/null
+++ b/src/main/scala/org/scadcop/solver/Solver.scala
@@ -0,0 +1,30 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.solver
+
+import org.scadcop.problem.{Context, DCOP}
+
+/**
+ * Abstract class representing a solver
+ * @param pb DCOP instance
+ */
+abstract class Solver(val pb : DCOP) {
+ var debug = false
+ var solvingTime : Long = 0
+
+ /**
+ * Returns an assignment
+ */
+ protected def solve() : Context
+
+ /**
+ * Returns an assignment and update solving time
+ */
+ def run() : Context = {
+ val startingTime = System.nanoTime()
+ val assignment = solve()
+ solvingTime = System.nanoTime() - startingTime
+ if (! assignment.sound()) throw new RuntimeException(s"Solver: the outcome\n $assignment\n for\n $pb is not sound")
+ assignment
+ }
+
+}
diff --git a/src/main/scala/org/scadcop/util/Main.scala b/src/main/scala/org/scadcop/util/Main.scala
new file mode 100644
index 0000000..7e3355b
--- /dev/null
+++ b/src/main/scala/org/scadcop/util/Main.scala
@@ -0,0 +1,31 @@
+// Copyright (C) Maxime MORGE 2020
+package org.scadcop.util
+
+import akka.actor.ActorSystem
+import org.scadcop.dfs.DFS
+import org.scadcop.solver.DistributedSolver
+
+/**
+ * Main application to test ADOPT on a toy example
+ */
+object Main {
+ import org.scadcop.problem.ToyExample._
+ def main(args: Array[String]): Unit = {
+ if (! pb.sound()) throw new RuntimeException("Pb is not sound")
+ println(pb)
+ if (! a1.sound()) throw new RuntimeException("A1 is not sound")
+ println("a1: " + a1)
+ println("a1's objective: " + a1.objective())
+ if (! a2.sound()) throw new RuntimeException("A2 is not sound")
+ println("a2: " + a2)
+ println("a2's objective: " + a2.objective())
+ val dfs =DFS(pb,x1)
+ println("DFS: "+dfs)
+ val system = ActorSystem("TestDistributedSolver")
+ val solver = new DistributedSolver(pb, system)
+ val assignment = solver.run()
+ println("Adopt outcome: " + assignment)
+ println("Adopt outcome objective: " + assignment.objective())
+ sys.exit(0)
+ }
+}
diff --git a/src/main/scala/org/scadcop/util/MathUtils.scala b/src/main/scala/org/scadcop/util/MathUtils.scala
new file mode 100644
index 0000000..4f7442d
--- /dev/null
+++ b/src/main/scala/org/scadcop/util/MathUtils.scala
@@ -0,0 +1,15 @@
+// Copyright (C) Maxime MORGE 2019
+package org.scadcop.util
+
+/**
+ * Compare floating-point numbers in Scala
+ *
+ */
+object MathUtils {
+ implicit class MathUtils(x: Double) {
+ val precision = 0.000001
+ def ~=(y: Double): Boolean = {
+ if ((x - y).abs < precision) true else false
+ }
+ }
+}
--
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