/// <remarks>Like <see cref="TryExecute(RecipeExecutorState, out RecipeExecutorState)"/>
/// but with a boolean parameter for throwing.</remarks>
private bool InternalExecute(RecipeExecutorState state, out RecipeExecutorState stateAfter, bool shouldThrow)
{
int boundaryLength = state.Boundary.Count;
if (!boundaryLength.IsMultipleOf(NumPeriods))
{
if (shouldThrow)
{
throw new PotentialRecipeExecutionException($"The length of the boundary ({boundaryLength}) is not a multiple of the number of periods ({NumPeriods}).");
}
stateAfter = null;
return(false);
}
int periodLength = boundaryLength / NumPeriods;
var atomicInstructions = Enumerable.Range(0, NumPeriods).Select(k => new AtomicGlueInstruction(k * periodLength + AtomicInstruction.Index, AtomicInstruction.Count, AtomicInstruction.CycleLength));
var compositeInstruction = new CompositeGlueInstruction(atomicInstructions);
if (shouldThrow)
{
state = compositeInstruction.Execute(state);
}
else if (!compositeInstruction.TryExecute(state, out state))
{
stateAfter = null;
return(false);
}
stateAfter = state;
return(true);
}
public IEnumerable <QuiverWithPotential <int> > GenerateQPsFromGivenBase(
RecipeExecutorState baseState,
int numPeriods,
int numRounds,
int maxCycleLength)
{
if (baseState == null)
{
throw new ArgumentNullException(nameof(baseState));
}
if (numPeriods <= 0)
{
throw new ArgumentOutOfRangeException(nameof(numPeriods));
}
if (numRounds < 0)
{
throw new ArgumentOutOfRangeException(nameof(numRounds));
}
if (maxCycleLength <= 2)
{
throw new ArgumentOutOfRangeException(nameof(maxCycleLength));
}
// TODO: Might want to validate baseState more carefully here
return(DoWork(baseState, numPeriods, numRounds, maxCycleLength));
}
private bool InternalExecute(RecipeExecutorState stateBefore, out RecipeExecutorState stateAfter, bool shouldThrow)
{
var newBoundary = new CircularList <(Arrow <int>, BoundaryArrowOrientation)>(stateBefore.Boundary);
stateAfter = new RecipeExecutorState
{
Potential = stateBefore.Potential,
NextVertex = stateBefore.NextVertex,
Boundary = newBoundary,
};
return(true);
}
private IEnumerable <QuiverWithPotential <int> > DoWork(RecipeExecutorState state, int numPeriods, int numRounds, int maxCycleLength)
{
if (numRounds == 0)
{
yield return(new QuiverWithPotential <int>(state.Potential));
yield break;
}
int numArrowsInPeriod = state.Boundary.Count / numPeriods;
foreach (int index in Enumerable.Range(0, numArrowsInPeriod))
{
var firstArrowOrientation = state.Boundary[index].Orientation;
for (int count = 1; count <= numArrowsInPeriod; count++)
{
var lastArrowOrientation = state.Boundary[index + count - 1].Orientation;
if (firstArrowOrientation != lastArrowOrientation)
{
break; // The path has arrows of different orientation, so try a new startIndex
}
for (int cycleLength = Math.Max(3, count + 1); cycleLength <= maxCycleLength; cycleLength++)
{
var instruction = new PeriodicAtomicGlueInstruction(new AtomicGlueInstruction(index, count, cycleLength), numPeriods);
if (!instruction.TryExecute(state, out var newState))
{
continue; // Fails only on "problematic arrows"? Also on bad input with GenerateQPsFromGivenBase
}
foreach (var qp in DoWork(newState, numPeriods, numRounds - 1, maxCycleLength))
{
yield return(qp);
}
}
}
}
}
/// <inheritdoc/>
public bool TryExecute(RecipeExecutorState stateBefore, out RecipeExecutorState stateAfter)
{
return(InternalExecute(stateBefore, out stateAfter, false));
}
/// <inheritdoc/>
public RecipeExecutorState Execute(RecipeExecutorState state)
{
InternalExecute(state, out var newState, true);
return(newState);
}
/// <remarks>Like <see cref="TryExecute(RecipeExecutorState, out RecipeExecutorState)"/>
/// but with a boolean parameter for throwing.</remarks>
private bool InternalExecute(RecipeExecutorState state, out RecipeExecutorState stateAfter, bool shouldThrow)
{
var oldPathTuples = state.Boundary.GetRange(Index, Count);
var oldPathArrows = oldPathTuples.Select(x => x.Arrow);
var oldPathOrientations = oldPathTuples.Select(x => x.Orientation);
if (!oldPathOrientations.AllAreEqual())
{
if (shouldThrow)
{
throw new PotentialRecipeExecutionException("The path in the boundary has arrows of different orientation.");
}
stateAfter = null;
return(false);
}
var oldPathOrientation = oldPathTuples.First().Orientation;
if (oldPathOrientation == BoundaryArrowOrientation.Left)
{
oldPathArrows = oldPathArrows.Reverse();
}
var oldPath = new Path <int>(oldPathArrows);
var newPathLength = CycleLength - Count;
var newPath = Utility.MakePath(oldPath.EndingPoint, oldPath.StartingPoint, newPathLength, state.NextVertex);
if (newPathLength == 1)
{
var newArrow = newPath.Arrows.Single();
// Bad cancellation
if (state.PotentiallyProblematicArrows.Contains(newArrow))
{
if (shouldThrow)
{
throw new PotentialRecipeExecutionException("The arrow of the singleton new path is already present in the potential.");
}
stateAfter = null;
return(false);
}
// 2-cycle (which is bad)
if (state.PotentiallyProblematicArrows.Contains(new Arrow <int>(newArrow.Target, newArrow.Source)))
{
if (shouldThrow)
{
throw new PotentialRecipeExecutionException("The anti-parallel of the arrow of the singleton new path is present in the potential.");
}
stateAfter = null;
return(false);
}
}
var newPathOrientation = oldPathOrientation.Reverse();
IEnumerable <Arrow <int> > newPathArrows = newPath.Arrows;
if (newPathOrientation == BoundaryArrowOrientation.Left)
{
newPathArrows = newPathArrows.Reverse();
}
var newPathTuples = newPathArrows.Select(a => (a, newPathOrientation));
var newCycle = new SimpleCycle <int>(oldPath.AppendPath(newPath));
int coefficient = newPathOrientation == BoundaryArrowOrientation.Right ? +1 : -1;
var newBoundary = new CircularList <(Arrow <int>, BoundaryArrowOrientation)>(state.Boundary);
newBoundary.ReplaceRange(Index, Count, newPathTuples);
var newPotentiallyProblematicArrows = new HashSet <Arrow <int> >(state.PotentiallyProblematicArrows);
if (Count == 1)
{
newPotentiallyProblematicArrows.Add(oldPath.Arrows.Single());
}
stateAfter = new RecipeExecutorState
{
Potential = state.Potential.AddCycle(newCycle, coefficient),
NextVertex = state.NextVertex + (newPath.LengthInVertices - 2),
Boundary = newBoundary,
PotentiallyProblematicArrows = newPotentiallyProblematicArrows
};
return(true);
}
private bool InternalExecute(RecipeExecutorState stateBefore, out RecipeExecutorState stateAfter, bool shouldThrow)
{
stateAfter = null;
// Normalize the index of every instruction for the current boundary
var instructions = atomicInstructions.Select(ai => new AtomicGlueInstruction(ai.Index.Modulo(stateBefore.Boundary.Count), ai.Count, ai.CycleLength)).ToList();
instructions.Sort((i1, i2) =>
{
int cmp = i1.Index.CompareTo(i2.Index);
if (cmp != 0)
{
return(cmp);
}
else
{
return(i1.Count.CompareTo(i2.Count));
}
});
if (!InstructionsHaveDisjointSupport())
{
if (shouldThrow)
{
throw new PotentialRecipeExecutionException("The atomic instructions do not have disjoint support.");
}
else
{
return(false);
}
}
// Execute the instructions from last to first in order to mostly avoid having to update the indices of the instructions
instructions.Reverse();
// If the support of last instruction wraps around, its execution will affect the indices of the previous instructions
// This can be solved either (1) by shifting the indices of all the previous instructions accordingly or
// (2) by rotating the boundary and shifting the indices of *all* instructions accordingly (including the last)
// (not that no inverse rotation is necessary).
// The former approach is used below
if (instructions.Count > 0)
{
var lastInstruction = instructions.First(); // Last instruction with the original order ("increasing")
int numWrappedAroundArrows = Math.Max(0, (lastInstruction.Index + lastInstruction.Count) - stateBefore.Boundary.Count);
if (numWrappedAroundArrows > 0)
{
instructions = instructions.Select((instr, index) => index == 0 ? instr : new AtomicGlueInstruction(instr.Index - numWrappedAroundArrows, instr.Count, instr.CycleLength)).ToList();
}
}
var state = stateBefore;
// Might be better to sort the list descendingly from the beginning, but reversing it here is easier
foreach (var instruction in instructions)
{
if (shouldThrow)
{
state = instruction.Execute(state);
}
else if (!instruction.TryExecute(state, out state))
{
return(false);
}
}
stateAfter = state;
return(true);
bool InstructionsHaveDisjointSupport()
{
int previousInstructionEnd = 0; // exclusive
foreach (var instruction in instructions)
{
if (instruction.Index < previousInstructionEnd)
{
return(false);
}
previousInstructionEnd = instruction.Index + instruction.Count;
}
return(true);
}
}
