public override ExplorerDecision <int[]> MapContext(PRG prg, int[] ranking, int numActions)
{
if (ranking == null || ranking.Length < 1)
{
throw new ArgumentException("Actions chosen by default policy must not be empty.");
}
var decision = this.explorer.MapContext(prg, ranking[0], ranking.Length);
MultiActionHelper.PutActionToList(decision.Value, ranking);
return(ExplorerDecision.Create(ranking, decision.ExplorerState, decision.ShouldRecord));
}
public override ExplorerDecision <int[]> MapContext(PRG random, float[] weights, int numActions)
{
var decision = this.explorer.MapContext(random, weights, numActions);
float actionProbability = 0f;
int[] chosenActions = MultiActionHelper.SampleWithoutReplacement(weights, weights.Length, random, ref actionProbability);
// action id is one-based
return(ExplorerDecision.Create(chosenActions,
new GenericExplorerState {
Probability = actionProbability
},
true));
}
public ExplorerDecision <int[]> MapContext(PRG random, int[] policyAction, int numActions)
{
MultiActionHelper.ValidateActionList(policyAction);
float epsilon = this.explore ? this.defaultEpsilon : 0f;
int[] chosenAction;
bool isExplore;
if (random.UniformUnitInterval() < epsilon)
{
// 1 ... n
chosenAction = Enumerable.Range(1, policyAction.Length).ToArray();
// 0 ... n - 2
for (int i = 0; i < policyAction.Length - 1; i++)
{
int swapIndex = random.UniformInt(i, policyAction.Length - 1);
int temp = chosenAction[swapIndex];
chosenAction[swapIndex] = chosenAction[i];
chosenAction[i] = temp;
}
isExplore = true;
}
else
{
chosenAction = policyAction;
isExplore = false;
}
EpsilonGreedySlateState explorerState = new EpsilonGreedySlateState
{
Epsilon = this.defaultEpsilon,
IsExplore = isExplore,
Ranking = policyAction
};
return(ExplorerDecision.Create(chosenAction, explorerState, true));
}
public override ExplorerDecision <int[]> MapContext(PRG random, float[] scores, int numActions)
{
if (scores == null || scores.Length < 1)
{
throw new ArgumentException("Scores returned by default policy must not be empty.");
}
var decision = this.explorer.MapContext(random, scores, numActions);
int numActionsVariable = scores.Length;
int[] chosenActions;
// Note: there might be a way using out generic parameters and explicit interface implementation to avoid the cast
float actionProbability = ((GenericExplorerState)decision.ExplorerState).Probability;
if (this.explore)
{
chosenActions = MultiActionHelper.SampleWithoutReplacement(scores, numActionsVariable, random, ref actionProbability);
}
else
{
// avoid linq to optimize perf
chosenActions = new int[numActionsVariable];
for (int i = 1; i <= numActionsVariable; i++)
{
chosenActions[i] = i;
}
// swap max-score action with the first one
int firstAction = chosenActions[0];
chosenActions[0] = chosenActions[decision.Value];
chosenActions[decision.Value] = firstAction;
}
return(ExplorerDecision.Create(chosenActions,
decision.ExplorerState,
decision.ShouldRecord));
}
