public double InventorySpaceUpperBound(double nextPeriodInventorySpaceLowerBound, double nextPeriodInventorySpaceUpperBound,
double currentPeriodMinInventory, double currentPeriodMaxInventory, double inventoryPercentLoss)
{
InjectWithdrawRange currentPeriodInjectWithdrawRangeAtMaxInventory = GetInjectWithdrawRange(currentPeriodMaxInventory);
double nextPeriodMaxInventoryFromThisPeriodMaxInventory = currentPeriodMaxInventory * (1 - inventoryPercentLoss)
+ currentPeriodInjectWithdrawRangeAtMaxInventory.MaxInjectWithdrawRate;
double nextPeriodMinInventoryFromThisPeriodMaxInventory = currentPeriodMaxInventory * (1 - inventoryPercentLoss)
+ currentPeriodInjectWithdrawRangeAtMaxInventory.MinInjectWithdrawRate;
if (nextPeriodMinInventoryFromThisPeriodMaxInventory <= nextPeriodInventorySpaceUpperBound &&
nextPeriodInventorySpaceLowerBound <= nextPeriodMaxInventoryFromThisPeriodMaxInventory)
{
// No need to solve root as next period inventory space can be reached from the current period max inventory
return(currentPeriodMaxInventory);
}
// TODO share code in method up to here with PiecewiseLinearInjectWithdrawConstraint
double?inventorySpaceUpper = null;
for (int i = 0; i < _injectWithdrawRanges.Length - 1; i++)
{
// TODO reuse values between loop iterations like in PiecewiseLinearInjectWithdrawConstraint, or not bother because will make code less clear?
double maxWithdrawRate = _injectWithdrawRanges[i].InjectWithdrawRange.MinInjectWithdrawRate;
double bracketLowerInventory = _injectWithdrawRanges[i].Inventory;
double bracketLowerInventoryAfterWithdraw = bracketLowerInventory * (1 - inventoryPercentLoss) + maxWithdrawRate;
double bracketUpperInventory = _injectWithdrawRanges[i + 1].Inventory;
double bracketUpperInventoryAfterWithdraw = bracketUpperInventory * (1 - inventoryPercentLoss) + maxWithdrawRate;
if (bracketLowerInventoryAfterWithdraw <= nextPeriodInventorySpaceUpperBound &&
nextPeriodInventorySpaceUpperBound <= bracketUpperInventoryAfterWithdraw)
{
// If there are multiple solutions we want to take the maximum one, so we keep overwriting the solution
inventorySpaceUpper = StorageHelper.InterpolateLinearAndSolve(bracketLowerInventory,
bracketLowerInventoryAfterWithdraw, bracketUpperInventory,
bracketUpperInventoryAfterWithdraw, nextPeriodInventorySpaceUpperBound);
}
}
if (inventorySpaceUpper == null)
{
throw new ApplicationException("Storage inventory constraints cannot be satisfied.");
}
return(inventorySpaceUpper.Value);
}
public StepInjectWithdrawConstraint([NotNull] IEnumerable <InjectWithdrawRangeByInventory> injectWithdrawRanges)
{
if (injectWithdrawRanges == null)
{
throw new ArgumentNullException(nameof(injectWithdrawRanges));
}
_injectWithdrawRanges = injectWithdrawRanges.OrderBy(injectWithdrawRange => injectWithdrawRange.Inventory)
.ToArray();
if (_injectWithdrawRanges.Length < 2)
{
throw new ArgumentException("Inject/withdraw ranges collection must contain at least two elements.", nameof(injectWithdrawRanges));
}
InjectWithdrawRange secondHighestInventoryRange = _injectWithdrawRanges[_injectWithdrawRanges.Length - 2].InjectWithdrawRange;
InjectWithdrawRange highestInventoryRange = _injectWithdrawRanges[_injectWithdrawRanges.Length - 1].InjectWithdrawRange;
if (!StorageHelper.EqualsWithinTol(secondHighestInventoryRange.MaxInjectWithdrawRate, highestInventoryRange.MaxInjectWithdrawRate, 1E-12))
{
throw new ArgumentException("Top two ratchets do not have he same max injection rate.", nameof(injectWithdrawRanges));
}
if (!StorageHelper.EqualsWithinTol(secondHighestInventoryRange.MinInjectWithdrawRate, highestInventoryRange.MinInjectWithdrawRate, 1E-12))
{
throw new ArgumentException("Top two ratchets do not have he same max withdrawal rate.", nameof(injectWithdrawRanges));
}
_inventories = _injectWithdrawRanges.Select(injectWithdrawRange => injectWithdrawRange.Inventory)
.ToArray();
if (_inventories.Length > 2)
{
for (int i = 1; i < _inventories.Length - 1; i++) // Don't check the last pair as these should have same inject/withdraw rates, as checked for above
{
if (_injectWithdrawRanges[i].InjectWithdrawRange.MaxInjectWithdrawRate > _injectWithdrawRanges[i - 1].InjectWithdrawRange.MaxInjectWithdrawRate)
{
throw new ArgumentException("Ratchet injection rates cannot increase with inventory.");
}
if (_injectWithdrawRanges[i].InjectWithdrawRange.MinInjectWithdrawRate > _injectWithdrawRanges[i - 1].InjectWithdrawRange.MinInjectWithdrawRate)
{
throw new ArgumentException("Ratchet withdrawal rates cannot decrease with inventory.");
}
}
}
}
public double InventorySpaceLowerBound(double nextPeriodInventorySpaceLowerBound, double nextPeriodInventorySpaceUpperBound,
double currentPeriodMinInventory, double currentPeriodMaxInventory, double inventoryPercentLoss)
{
InjectWithdrawRange currentPeriodInjectWithdrawRangeAtMinInventory = GetInjectWithdrawRange(currentPeriodMinInventory);
double nextPeriodMaxInventoryFromThisPeriodMinInventory = currentPeriodMinInventory * (1 - inventoryPercentLoss)
+ currentPeriodInjectWithdrawRangeAtMinInventory.MaxInjectWithdrawRate;
double nextPeriodMinInventoryFromThisPeriodMinInventory = currentPeriodMinInventory * (1 - inventoryPercentLoss)
+ currentPeriodInjectWithdrawRangeAtMinInventory.MinInjectWithdrawRate;
if (nextPeriodMinInventoryFromThisPeriodMinInventory <= nextPeriodInventorySpaceUpperBound &&
nextPeriodInventorySpaceLowerBound <= nextPeriodMaxInventoryFromThisPeriodMinInventory)
{
// No need to solve root as next period inventory space can be reached from the current period min inventory
return(currentPeriodMinInventory);
}
// Search for inventory bracket
double bracketLowerInventory = _injectWithdrawRanges[0].Inventory;
double bracketLowerInventoryAfterInject = nextPeriodMaxInventoryFromThisPeriodMinInventory;
for (int i = 1; i < _injectWithdrawRanges.Length; i++)
{
InjectWithdrawRangeByInventory bracketUpperDecisionRange = _injectWithdrawRanges[i];
double bracketUpperInventory = bracketUpperDecisionRange.Inventory;
double bracketUpperInventoryAfterInject = bracketUpperInventory * (1 - inventoryPercentLoss) +
bracketUpperDecisionRange.InjectWithdrawRange.MaxInjectWithdrawRate;
if (bracketLowerInventoryAfterInject <= nextPeriodInventorySpaceLowerBound &&
nextPeriodInventorySpaceLowerBound <= bracketUpperInventoryAfterInject)
{
double inventorySpaceLower = StorageHelper.InterpolateLinearAndSolve(bracketLowerInventory,
bracketLowerInventoryAfterInject, bracketUpperInventory,
bracketUpperInventoryAfterInject, nextPeriodInventorySpaceLowerBound);
return(inventorySpaceLower);
}
bracketLowerInventoryAfterInject = bracketUpperInventoryAfterInject;
bracketLowerInventory = bracketUpperInventory;
}
throw new ApplicationException("Storage inventory constraints cannot be satisfied.");
}
public void Deconstruct(out double inventory, out InjectWithdrawRange injectWithdrawRange)
{
inventory = Inventory;
injectWithdrawRange = InjectWithdrawRange;
}
public InjectWithdrawRangeByInventory(double inventory, [NotNull] InjectWithdrawRange injectWithdrawRange)
{
Inventory = inventory;
InjectWithdrawRange = injectWithdrawRange ?? throw new ArgumentNullException(nameof(injectWithdrawRange));
}
public static double[] CalculateBangBangDecisionSet(InjectWithdrawRange injectWithdrawRange, double currentInventory, double inventoryLoss,
double nextStepMinInventory, double nextStepMaxInventory, double numericalTolerance, int numExtraDecisions = 0) // TODO remove default value of zero
{
if (nextStepMinInventory > nextStepMaxInventory)
{
throw new ArgumentException($"Parameter {nameof(nextStepMinInventory)} value cannot be higher than parameter {nameof(nextStepMaxInventory)} value.");
}
if (numExtraDecisions < 0)
{
throw new ArgumentException($"Parameter {nameof(numExtraDecisions)} must be non-negative.", nameof(numExtraDecisions));
}
double inventoryAfterLoss = currentInventory - inventoryLoss;
double inventoryAfterMaxWithdrawal = injectWithdrawRange.MinInjectWithdrawRate + inventoryAfterLoss;
double yieldedWithdrawalRate;
if (inventoryAfterMaxWithdrawal > nextStepMaxInventory) // Max withdrawal still above next step max inventory
{
if (inventoryAfterMaxWithdrawal - nextStepMaxInventory < numericalTolerance)
{
// Next period inventory is breached, but only by a small amount, probably due to root finding in PolynomialInjectWithdrawConstraint during inventory space reduction
yieldedWithdrawalRate = nextStepMaxInventory - inventoryAfterLoss; // TODO unit test code reaching here
}
else
{
throw new ArgumentException("Inventory constraints cannot be fulfilled. This could potentially be fixed by increasing the numerical tolerance.");
}
}
else if (inventoryAfterMaxWithdrawal > nextStepMinInventory)
{
yieldedWithdrawalRate = injectWithdrawRange.MinInjectWithdrawRate; // Unconstrained withdrawal
}
else
{
yieldedWithdrawalRate = nextStepMinInventory - inventoryAfterLoss; //constrained withdrawal (could be made positive to injection)
}
double inventoryAfterMaxInjection = injectWithdrawRange.MaxInjectWithdrawRate + inventoryAfterLoss;
double yieldedInjectionRate;
if (inventoryAfterMaxInjection < nextStepMinInventory) // Max injection still below next step min inventory constraint
{
if (nextStepMinInventory - inventoryAfterMaxInjection < numericalTolerance)
{
// Next period inventory is breached, but only by a small amount, probably due to root finding in PolynomialInjectWithdrawConstraint during inventory space reduction
yieldedInjectionRate = nextStepMinInventory - inventoryAfterLoss; // TODO unit test code reaching here
}
else
{
throw new ArgumentException("Inventory constraints cannot be fulfilled. This could potentially be fixed by increasing the numerical tolerance.");
}
}
else if (inventoryAfterMaxInjection < nextStepMaxInventory)
{
yieldedInjectionRate = injectWithdrawRange.MaxInjectWithdrawRate; // Unconstrained injection
}
else
{
yieldedInjectionRate = nextStepMaxInventory - inventoryAfterLoss; // Constrained injection (could be made negative to withdrawal)
}
double[] decisionSet;
if (yieldedWithdrawalRate >= 0.0 || yieldedInjectionRate <= 0.0) // No zero decision
{
if (numExtraDecisions > 0)
{
decisionSet = new double[numExtraDecisions + 2];
decisionSet[0] = yieldedWithdrawalRate;
decisionSet[decisionSet.Length - 1] = yieldedInjectionRate;
PopulateExtraDecisions(yieldedWithdrawalRate, yieldedInjectionRate, numExtraDecisions, new Span <double>(decisionSet, 1, numExtraDecisions));
}
else
{
decisionSet = new double[] { yieldedWithdrawalRate, yieldedInjectionRate }
};
}
else
{
if (numExtraDecisions > 0)
{
decisionSet = new double[numExtraDecisions * 2 + 3];
decisionSet[0] = yieldedWithdrawalRate;
decisionSet[decisionSet.Length - 1] = yieldedInjectionRate;
PopulateExtraDecisions(yieldedWithdrawalRate, 0, numExtraDecisions, new Span <double>(decisionSet, 1, numExtraDecisions));
PopulateExtraDecisions(0, yieldedInjectionRate, numExtraDecisions, new Span <double>(decisionSet, numExtraDecisions + 2, numExtraDecisions));
}
else
{
decisionSet = new double[] { yieldedWithdrawalRate, 0.0, yieldedInjectionRate }
};
}
return(decisionSet);
// TODO case of yieldedWithdrawalRate equals to yieldedInjectionRate?
}
public ConstantInjectWithdrawConstraint([NotNull] InjectWithdrawRange injectWithdrawRange)
{
_injectWithdrawRange = injectWithdrawRange ?? throw new ArgumentNullException(nameof(injectWithdrawRange));
}
public ConstantInjectWithdrawConstraint(double minInjectWithdrawRate, double maxInjectWithdrawRate)
{
_injectWithdrawRange = new InjectWithdrawRange(minInjectWithdrawRate, maxInjectWithdrawRate);
}