/// <summary>
/// Generates up to n valid binary combinations of all binary configuration options in the given model.
/// In case n < 0 all valid binary combinations will be generated.
/// </summary>
/// <param name="m">The variability model containing the binary options and their constraints.</param>
/// <param name="n">The maximum number of samples that will be generated.</param>
/// <returns>Returns a list of configurations, in which a configuration is a list of SELECTED binary options (deselected options are not present)</returns>
public List <List <BinaryOption> > GenerateUpToNFast(VariabilityModel m, int n)
{
List <List <BinaryOption> > configurations = new List <List <BinaryOption> >();
List <CspTerm> variables = new List <CspTerm>();
Dictionary <BinaryOption, CspTerm> elemToTerm = new Dictionary <BinaryOption, CspTerm>();
Dictionary <CspTerm, BinaryOption> termToElem = new Dictionary <CspTerm, BinaryOption>();
ConstraintSystem S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, m);
ConstraintSolverSolution soln = S.Solve();
// TODO: Better solution than magic number?
while (soln.HasFoundSolution && (configurations.Count < n || n < 0))
{
List <BinaryOption> config = new List <BinaryOption>();
foreach (CspTerm cT in variables)
{
if (soln.GetIntegerValue(cT) == 1)
{
config.Add(termToElem[cT]);
}
}
//THese should always be new configurations
// if(!Configuration.containsBinaryConfiguration(configurations, config))
configurations.Add(config);
soln.GetNext();
}
return(configurations);
}
/// <summary>
/// Generates all valid binary combinations of all binary configurations options in the given model
/// </summary>
/// <param name="vm">The variability model containing the binary options and their constraints.</param>
/// <returns>Returns a list of configurations, in which a configuration is a list of SELECTED binary options (deselected options are not present)</returns>
public List <List <BinaryOption> > generateAllVariantsFast(VariabilityModel vm)
{
List <List <BinaryOption> > configurations = new List <List <BinaryOption> >();
List <CspTerm> variables = new List <CspTerm>();
Dictionary <BinaryOption, CspTerm> elemToTerm = new Dictionary <BinaryOption, CspTerm>();
Dictionary <CspTerm, BinaryOption> termToElem = new Dictionary <CspTerm, BinaryOption>();
ConstraintSystem S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, vm);
ConstraintSolverSolution soln = S.Solve();
while (soln.HasFoundSolution)
{
List <BinaryOption> config = new List <BinaryOption>();
foreach (CspTerm cT in variables)
{
if (soln.GetIntegerValue(cT) == 1)
{
config.Add(termToElem[cT]);
}
}
//THese should always be new configurations
// if(!Configuration.containsBinaryConfiguration(configurations, config))
configurations.Add(config);
soln.GetNext();
}
return(configurations);
}
/// <summary>
/// Checks whether the boolean selection is valid w.r.t. the variability model. Does not check for numeric options' correctness.
/// </summary>
/// <param name="config">The list of binary options that are SELECTED (only selected options must occur in the list).</param>
/// <param name="vm">The variability model that represents the context of the configuration.</param>
/// <param name="partialConfiguration">Whether the given list of options represents only a partial configuration. This means that options not in config might be additionally select to obtain a valid configuration.</param>
/// <returns>True if it is a valid selection w.r.t. the VM, false otherwise</returns>
public bool checkConfigurationSAT(List <BinaryOption> config, VariabilityModel vm, bool partialConfiguration)
{
List <CspTerm> variables = new List <CspTerm>();
Dictionary <BinaryOption, CspTerm> elemToTerm = new Dictionary <BinaryOption, CspTerm>();
Dictionary <CspTerm, BinaryOption> termToElem = new Dictionary <CspTerm, BinaryOption>();
ConstraintSystem S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, vm);
//Feature Selection
foreach (BinaryOption binayOpt in elemToTerm.Keys)
{
CspTerm term = elemToTerm[binayOpt];
if (config.Contains(binayOpt))
{
S.AddConstraints(S.Implies(S.True, term));
}
else if (!partialConfiguration)
{
S.AddConstraints(S.Implies(S.True, S.Not(term)));
}
}
ConstraintSolverSolution sol = S.Solve();
if (sol.HasFoundSolution)
{
return(true);
}
else
{
return(false);
}
}
/// <summary>
/// The method aims at finding a configuration which is similar to the given configuration, but does not contain the optionToBeRemoved. If further options need to be removed from the given configuration, they are outputed in removedElements.
/// Idea: Encode this as a CSP problem. We aim at finding a configuration that maximizes a goal. Each option of the given configuration gets a large value assigned. All other options of the variability model gets a negative value assigned.
/// We will further create a boolean constraint that forbids selecting the optionToBeRemoved. Now, we find an optimal valid configuration.
/// </summary>
/// <param name="optionToBeRemoved">The binary configuration option that must not be part of the new configuration.</param>
/// <param name="originalConfig">The configuration for which we want to find a similar one.</param>
/// <param name="removedElements">If further options need to be removed from the given configuration to build a valid configuration, they are outputed in this list.</param>
/// <param name="vm">The variability model containing all options and their constraints.</param>
/// <returns>A configuration that is valid, similar to the original configuration and does not contain the optionToBeRemoved.</returns>
public List <BinaryOption> GenerateConfigWithoutOption(BinaryOption optionToBeRemoved, List <BinaryOption> originalConfig, out List <BinaryOption> removedElements, VariabilityModel vm)
{
List <CspTerm> variables = new List <CspTerm>();
Dictionary <BinaryOption, CspTerm> elemToTerm = new Dictionary <BinaryOption, CspTerm>();
Dictionary <CspTerm, BinaryOption> termToElem = new Dictionary <CspTerm, BinaryOption>();
ConstraintSystem S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, vm);
removedElements = new List <BinaryOption>();
//Forbid the selection of this configuration option
CspTerm optionToRemove = elemToTerm[optionToBeRemoved];
S.AddConstraints(S.Implies(S.True, S.Not(optionToRemove)));
//Defining Goals
CspTerm[] finalGoals = new CspTerm[variables.Count];
int r = 0;
foreach (var term in variables)
{
if (originalConfig.Contains(termToElem[term]))
{
finalGoals[r] = term * -1000; //Since we minimize, we put a large negative value of an option that is within the original configuration to increase chances that the option gets selected again
}
else
{
finalGoals[r] = variables[r] * 10000;//Positive number will lead to a small chance that an option gets selected when it is not in the original configuration
}
r++;
}
S.TryAddMinimizationGoals(S.Sum(finalGoals));
ConstraintSolverSolution soln = S.Solve();
List <BinaryOption> tempConfig = new List <BinaryOption>();
if (soln.HasFoundSolution && soln.Quality == ConstraintSolverSolution.SolutionQuality.Optimal)
{
tempConfig.Clear();
foreach (CspTerm cT in variables)
{
if (soln.GetIntegerValue(cT) == 1)
{
tempConfig.Add(termToElem[cT]);
}
}
//Adding the options that have been removed from the original configuration
foreach (var opt in originalConfig)
{
if (!tempConfig.Contains(opt))
{
removedElements.Add(opt);
}
}
return(tempConfig);
}
return(null);
}
private void InitializeCache(VariabilityModel vm, int numberSelectedFeatures)
{
List <CspTerm> variables;
Dictionary <CspTerm, BinaryOption> termToElem;
ConstraintSystem S;
Dictionary <BinaryOption, CspTerm> elemToTerm;
// Build the constraint system
S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, vm);
// The first goal of this method is, to have an exact number of features selected
S.AddConstraints(S.ExactlyMofN(numberSelectedFeatures, variables.ToArray()));
this._constraintSystemCache.Add(numberSelectedFeatures,
new ConstraintSystemCache(S, variables, elemToTerm, termToElem));
}
/// <summary>
/// Checks whether the boolean selection of a configuration is valid w.r.t. the variability model. Does not check for numeric options' correctness.
/// </summary>
/// <param name="c">The configuration that needs to be checked.</param>
/// <param name="vm">The variability model that represents the context of the configuration.</param>
/// <returns>True if it is a valid selection w.r.t. the VM, false otherwise</returns>
public bool checkConfigurationSAT(Configuration c, VariabilityModel vm)
{
List <CspTerm> variables = new List <CspTerm>();
Dictionary <BinaryOption, CspTerm> elemToTerm = new Dictionary <BinaryOption, CspTerm>();
Dictionary <CspTerm, BinaryOption> termToElem = new Dictionary <CspTerm, BinaryOption>();
ConstraintSystem S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, vm);
//Feature Selection
foreach (BinaryOption binayOpt in elemToTerm.Keys)
{
CspTerm term = elemToTerm[binayOpt];
if (c.getBinaryOptions(BinaryOption.BinaryValue.Selected).Contains(binayOpt))
{
S.AddConstraints(S.Implies(S.True, term));
}
else
{
S.AddConstraints(S.Implies(S.True, S.Not(term)));
}
}
ConstraintSolverSolution sol = S.Solve();
if (sol.HasFoundSolution)
{
int count = 0;
foreach (CspTerm cT in variables)
{
if (sol.GetIntegerValue(cT) == 1)
{
count++;
}
}
//-1??? Needs testing TODO
if (count - 1 != c.getBinaryOptions(BinaryOption.BinaryValue.Selected).Count)
{
return(false);
}
return(true);
}
else
{
return(false);
}
}
/// <summary>
/// Creates a sample of configurations, by iteratively adding a configuration that has the maximal manhattan distance
/// to the configurations that were previously selected.
/// </summary>
/// <param name="vm">The domain for sampling.</param>
/// <param name="minimalConfiguration">A minimal configuration that will be used as starting point.</param>
/// <param name="numberToSample">The number of configurations that should be sampled.</param>
/// <param name="optionWeight">Weight assigned to optional binary options.</param>
/// <returns>A list of distance maximized configurations.</returns>
public List <List <BinaryOption> > DistanceMaximization(VariabilityModel vm, List <BinaryOption> minimalConfiguration, int numberToSample, int optionWeight)
{
List <Configuration> sample = new List <Configuration>();
List <List <BinaryOption> > convertedSample = new List <List <BinaryOption> >();
sample.Add(new Configuration(minimalConfiguration));
convertedSample.Add(minimalConfiguration);
List <CspTerm> variables = new List <CspTerm>();
Dictionary <BinaryOption, CspTerm> elemToTerm = new Dictionary <BinaryOption, CspTerm>();
Dictionary <CspTerm, BinaryOption> termToElem = new Dictionary <CspTerm, BinaryOption>();
while (sample.Count < numberToSample)
{
ConstraintSystem S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, vm);
addDistanceMaximiationGoal(sample, vm, elemToTerm, S, optionWeight);
ConstraintSolverSolution sol = S.Solve();
if (sol.HasFoundSolution)
{
List <BinaryOption> solution = new List <BinaryOption>();
foreach (CspTerm cT in variables)
{
if (sol.GetIntegerValue(cT) == 1)
{
solution.Add(termToElem[cT]);
}
}
S.ResetSolver();
convertedSample.Add(solution);
sample.Add(new Configuration(solution));
}
else
{
GlobalState.logInfo.logLine("No more solutions available.");
return(convertedSample);
}
}
return(convertedSample);
}
/// <summary>
/// Simulates a simple method to get valid configurations of binary options of a variability model. The randomness is simulated by the modulu value.
/// We take only the modulu'th configuration into the result set based on the CSP solvers output. If modulu is larger than the number of valid variants, the result set is empty.
/// </summary>
/// <param name="vm">The variability model containing the binary options and their constraints.</param>
/// <param name="treshold">Maximum number of configurations</param>
/// <param name="modulu">Each configuration that is % modulu == 0 is taken to the result set</param>
/// <returns>Returns a list of configurations, in which a configuration is a list of SELECTED binary options (deselected options are not present</returns>
public List <List <BinaryOption> > GenerateRandomVariants(VariabilityModel vm, int treshold, int modulu)
{
List <CspTerm> variables = new List <CspTerm>();
Dictionary <BinaryOption, CspTerm> elemToTerm = new Dictionary <BinaryOption, CspTerm>();
Dictionary <CspTerm, BinaryOption> termToElem = new Dictionary <CspTerm, BinaryOption>();
ConstraintSystem S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, vm);
List <List <BinaryOption> > erglist = new List <List <BinaryOption> >();
ConstraintSolverSolution soln = S.Solve();
List <List <BinaryOption> > allConfigs = new List <List <BinaryOption> >();
while (soln.HasFoundSolution)
{
soln.GetNext();
List <BinaryOption> tempConfig = new List <BinaryOption>();
foreach (CspTerm cT in variables)
{
if (soln.GetIntegerValue(cT) == 1)
{
tempConfig.Add(termToElem[cT]);
}
}
if (tempConfig.Contains(null))
{
tempConfig.Remove(null);
}
allConfigs.Add(tempConfig);
}
Random r = new Random(modulu);
for (int i = 0; i < treshold; i++)
{
erglist.Add(allConfigs[r.Next(allConfigs.Count)]);
}
return(erglist);
}
/// <summary>
/// Based on a given (partial) configuration and a variability, we aim at finding all optimally maximal or minimal (in terms of selected binary options) configurations.
/// </summary>
/// <param name="config">The (partial) configuration which needs to be expaned to be valid.</param>
/// <param name="vm">Variability model containing all options and their constraints.</param>
/// <param name="minimize">If true, we search for the smallest (in terms of selected options) valid configuration. If false, we search for the largest one.</param>
/// <param name="unwantedOptions">Binary options that we do not want to become part of the configuration. Might be part if there is no other valid configuration without them</param>
/// <returns>A list of configurations that satisfies the VM and the goal (or null if there is none).</returns>
public List <List <BinaryOption> > MaximizeConfig(List <BinaryOption> config, VariabilityModel vm, bool minimize, List <BinaryOption> unwantedOptions)
{
List <CspTerm> variables = new List <CspTerm>();
Dictionary <BinaryOption, CspTerm> elemToTerm = new Dictionary <BinaryOption, CspTerm>();
Dictionary <CspTerm, BinaryOption> termToElem = new Dictionary <CspTerm, BinaryOption>();
ConstraintSystem S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, vm);
//Feature Selection
if (config != null)
{
foreach (BinaryOption binOpt in config)
{
CspTerm term = elemToTerm[binOpt];
S.AddConstraints(S.Implies(S.True, term));
}
}
//Defining Goals
CspTerm[] finalGoals = new CspTerm[variables.Count];
for (int r = 0; r < variables.Count; r++)
{
if (minimize == true)
{
BinaryOption binOpt = termToElem[variables[r]];
if (unwantedOptions != null && (unwantedOptions.Contains(binOpt) && !config.Contains(binOpt)))
{
finalGoals[r] = variables[r] * 10000;
}
else
{
// Element is part of an altnerative Group ... we want to select always the same option of the group, so we give different weights to the member of the group
//Functionality deactivated... todo needs further handling
/*if (binOpt.getAlternatives().Count != 0)
* {
* finalGoals[r] = variables[r] * (binOpt.getID() * 10);
* }
* else
* {*/
finalGoals[r] = variables[r] * 1;
//}
// wenn in einer alternative, dann bekommt es einen wert nach seiner reihenfolge
// id mal 10
}
}
else
{
finalGoals[r] = variables[r] * -1; // dynamic cost map
}
}
S.TryAddMinimizationGoals(S.Sum(finalGoals));
ConstraintSolverSolution soln = S.Solve();
List <string> erg2 = new List <string>();
List <BinaryOption> tempConfig = new List <BinaryOption>();
List <List <BinaryOption> > resultConfigs = new List <List <BinaryOption> >();
while (soln.HasFoundSolution && soln.Quality == ConstraintSolverSolution.SolutionQuality.Optimal)
{
tempConfig.Clear();
foreach (CspTerm cT in variables)
{
if (soln.GetIntegerValue(cT) == 1)
{
tempConfig.Add(termToElem[cT]);
}
}
if (minimize && tempConfig != null)
{
resultConfigs.Add(tempConfig);
break;
}
if (!Configuration.containsBinaryConfiguration(resultConfigs, tempConfig))
{
resultConfigs.Add(tempConfig);
}
soln.GetNext();
}
return(resultConfigs);
}
/// <summary>
/// This method searches for a corresponding methods in the dynamically loaded assemblies and calls it if found. It prefers due to performance reasons the Microsoft Solver Foundation implementation.
/// </summary>
/// <param name="config">The (partial) configuration which needs to be expaned to be valid.</param>
/// <param name="vm">Variability model containing all options and their constraints.</param>
/// <param name="minimize">If true, we search for the smallest (in terms of selected options) valid configuration. If false, we search for the largest one.</param>
/// <param name="unWantedOptions">Binary options that we do not want to become part of the configuration. Might be part if there is no other valid configuration without them.</param>
/// <returns>The valid configuration (or null if there is none) that satisfies the VM and the goal.</returns>
public List <BinaryOption> MinimizeConfig(List <BinaryOption> config, VariabilityModel vm, bool minimize, List <BinaryOption> unWantedOptions)
{
List <CspTerm> variables = new List <CspTerm>();
Dictionary <BinaryOption, CspTerm> elemToTerm = new Dictionary <BinaryOption, CspTerm>();
Dictionary <CspTerm, BinaryOption> termToElem = new Dictionary <CspTerm, BinaryOption>();
ConstraintSystem S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, vm);
//Feature Selection
foreach (BinaryOption binOpt in config)
{
CspTerm term = elemToTerm[binOpt];
S.AddConstraints(S.Implies(S.True, term));
}
//Defining Goals
CspTerm[] finalGoals = new CspTerm[variables.Count];
for (int r = 0; r < variables.Count; r++)
{
if (minimize == true)
{
if (unWantedOptions != null && (unWantedOptions.Contains(termToElem[variables[r]]) && !config.Contains(termToElem[variables[r]])))
{
finalGoals[r] = variables[r] * 100;
}
else
{
finalGoals[r] = variables[r] * 1;
}
}
else
{
finalGoals[r] = variables[r] * -1; // dynamic cost map
}
}
S.TryAddMinimizationGoals(S.Sum(finalGoals));
ConstraintSolverSolution soln = S.Solve();
List <string> erg2 = new List <string>();
List <BinaryOption> tempConfig = new List <BinaryOption>();
while (soln.HasFoundSolution)
{
tempConfig.Clear();
foreach (CspTerm cT in variables)
{
if (soln.GetIntegerValue(cT) == 1)
{
tempConfig.Add(termToElem[cT]);
}
}
if (minimize && tempConfig != null)
{
break;
}
soln.GetNext();
}
return(tempConfig);
}
/// <summary>
/// This method has the objective to sample a configuration where n features are selected
/// </summary>
/// <returns>The first fitting configuration.</returns>
/// <param name="vm">The variability model.</param>
/// <param name="numberSelectedFeatures">The number of features that should be selected.</param>
/// <param name="featureWeight">The weight of the features to minimize.</param>
/// <param name="sampledConfigurations">The sampled configurations until now.</param>
public List <BinaryOption> GenerateConfigurationFromBucket(VariabilityModel vm, int numberSelectedFeatures, Dictionary <List <BinaryOption>, int> featureWeight, Configuration lastSampledConfiguration)
{
if (this._constraintSystemCache == null)
{
this._constraintSystemCache = new Dictionary <int, ConstraintSystemCache>();
}
List <CspTerm> variables;
Dictionary <BinaryOption, CspTerm> elemToTerm;
Dictionary <CspTerm, BinaryOption> termToElem;
ConstraintSystem S;
if (this._constraintSystemCache.Keys.Contains(numberSelectedFeatures))
{
variables = _constraintSystemCache[numberSelectedFeatures].GetVariables();
elemToTerm = _constraintSystemCache[numberSelectedFeatures].GetElemToTermMapping();
termToElem = _constraintSystemCache[numberSelectedFeatures].GetTermToElemMapping();
S = _constraintSystemCache[numberSelectedFeatures].GetConstraintSystem();
S.ResetSolver();
S.RemoveAllMinimizationGoals();
// Add the missing configurations
AddBinaryConfigurationsToConstraintSystem(vm, S, lastSampledConfiguration, elemToTerm);
}
else
{
variables = new List <CspTerm>();
elemToTerm = new Dictionary <BinaryOption, CspTerm>();
termToElem = new Dictionary <CspTerm, BinaryOption>();
// Build the constraint system
S = CSPsolver.getConstraintSystem(out variables, out elemToTerm, out termToElem, vm);
// The first goal of this method is, to have an exact number of features selected
S.AddConstraints(S.ExactlyMofN(numberSelectedFeatures, variables.ToArray()));
if (lastSampledConfiguration != null)
{
// Add the previous configurations as constraints
AddBinaryConfigurationsToConstraintSystem(vm, S, lastSampledConfiguration, elemToTerm);
}
this._constraintSystemCache.Add(numberSelectedFeatures, new ConstraintSystemCache(S, variables, elemToTerm, termToElem));
}
// Next, solve the constraint system
ConstraintSolverSolution soln = S.Solve();
List <BinaryOption> tempConfig = new List <BinaryOption>();
if (soln.HasFoundSolution)
{
tempConfig.Clear();
foreach (CspTerm cT in variables)
{
if (soln.GetIntegerValue(cT) == 1)
{
tempConfig.Add(termToElem[cT]);
}
}
}
else
{
return(null);
}
return(tempConfig);
}