public void Push(LtmdpChosenValue value)
{
if (_memoryBuffer.SizeInBytes <= Count * sizeof(LtmdpChosenValue))
{
_memoryBuffer.Resize(_memoryBuffer.SizeInBytes * 2, zeroMemory: true);
_buffer = (LtmdpChosenValue *)_memoryBuffer.Pointer;
}
_buffer[Count++] = value;
}
/// <summary>
/// Sets the choices that should be made during the next step.
/// </summary>
/// <param name="choices">The choices that should be made.</param>
internal override void SetChoices(int[] choices)
{
Requires.NotNull(choices, nameof(choices));
for (var i = 0; i < choices.Length; i++)
{
var newChosenValue =
new LtmdpChosenValue
{
ContinuationId = i,
OptionIndex = choices[i]
};
_chosenValues.Push(newChosenValue);
_valueCount.Push(0);
}
}
public override bool PrepareNextPath()
{
if (_choiceIndex != _valueCount.Count - 1)
{
throw new NondeterminismException();
}
// Reset the choice counter as each path starts from the beginning
_choiceIndex = -1;
// If this is the first path of the state, we definitely have to enumerate it
if (_firstPath)
{
_firstPath = false;
return(true);
}
// Let's go through the entire stack to determine what we have to do next
while (_chosenValues.Count > 0)
{
// Remove the value we've chosen last -- we've already chosen it, so we're done with it
var chosenValue = _chosenValues.Remove();
// If we have at least one other value to choose, let's do that next
if (_valueCount.Peek() > chosenValue.OptionIndex + 1)
{
_continuationId = chosenValue.ContinuationId + 1;
var newChosenValue =
new LtmdpChosenValue
{
OptionIndex = chosenValue.OptionIndex + 1,
ContinuationId = _continuationId,
};
_chosenValues.Push(newChosenValue);
return(true);
}
// Otherwise, we've chosen all values of the last choice, so we're done with it
_valueCount.Remove();
}
AssertThatDatastructureIsIntact();
// If we reach this point, we know that we've chosen all values of all choices, so there are no further paths
return(false);
}
public override int HandleProbabilisticChoice(int valueCount)
{
++_choiceIndex;
// If we have a preselected value that we should choose for the current path, return it
var chosenValuesMaxIndex = _chosenValues.Count - 1;
if (_choiceIndex <= chosenValuesMaxIndex)
{
return(_chosenValues[_choiceIndex].OptionIndex);
}
// We haven't encountered this choice before; store the value count and return the first value
_valueCount.Push(valueCount);
var oldContinuationId = _continuationId;
_continuationId = _nextFreeContinuationId;
var newChosenValue =
new LtmdpChosenValue
{
OptionIndex = 0,
ContinuationId = _continuationId,
};
_chosenValues.Push(newChosenValue);
_nextFreeContinuationId = _nextFreeContinuationId + valueCount;
LtmdpStepGraph.ProbabilisticSplit(oldContinuationId, _continuationId, _continuationId + valueCount - 1);
// set default values
var defaultValue = 1.0 / valueCount;
for (var i = 0; i < valueCount; i++)
{
LtmdpStepGraph.SetProbabilityOfContinuationId(_continuationId + i, defaultValue);
}
return(0);
}