InformationLevel

Unrestricted reservoir to store information

Diagram

Information

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This is the general, unrestricted reservoir of the system dynamics methodology, it accumulates information transported by flow components connected to the StockPorts. The InformationLevel can become negative.

Notes

The inflow and outflow →StockPorts are only indicative; in general the reservoir may be filled or drained by flows connected to either port.

The parameters maxValue and minValue allow to define an admissable range. It can be monitored by an assert using useAssert = true in the Advanced tab. The switch causeError controls whether an error or a warning is to be raised.

The parameter init in the Advanced tab allows to select →InitializationOptions:
- FixedValue (default) will use the parameter initialValue to determine the initial value.
- SteadyState will introduce the equation der(x) = 0 in order to find an initial value that establishes equilibrium.
  (Note: Such a solution may not exist and to avoid trivial solution in many cases initialValue -- in this case used as a start value for numerical iteration -- should be set to a value different from zero.)
- Free there will be no initial equation and thus the solver is free in solving the initial value problem.

There is an optional →StockInfoOutput connector.

Parameters (7)

init	Value: modelSettings.init Type: InitializationOptions Description: Provide InitializationOptions (Free, FixedValue, SteadyState)
hasStockInfoOutput	Value: false Type: Boolean Description: = true, if a StockInfoOutput should be added to the stock
initialValue	Value: 0 Type: OutputType Description: Initial level (should be different from 0 to find non-trivial steady state solution)
maxValue	Value: inf Type: OutputType Description: Maximum admissable value
minValue	Value: -inf Type: OutputType Description: Minimum admissable value
useAssert	Value: false Type: Boolean Description: = true, if leaving the admissable range is to cause an error or warning
causeError	Value: true Type: Boolean Description: = true, if leaving the admissable range is to cause an error instead of simply a warning

Connectors (6)

	y	Type: RealOutput Description: Level or rate information
	y1	Type: RealOutput Description: Level or rate information
	y2	Type: RealOutput Description: Level or rate information
	inflow	Type: StockPort Description: Inflow port of the stock
	outflow	Type: StockPort Description: Outflow port of the stock
	y_stockInfo	Type: StockInfoOutput Description: Optional StockInfoOutput

Components (3)

	modelSettings	Type: ModelSettings Description: Setting important global variables within a model
	stockInfoSensor	Type: StockInfo Description: Collect basic stock-related information for basic stocks
	rangeControl	Type: RangeAssert Description: Use assert() to check admissable values

modelSettings

Type: ModelSettings

Description: Setting important global variables within a model

stockInfoSensor

Type: StockInfo

Description: Collect basic stock-related information for basic stocks

rangeControl

Type: RangeAssert

Description: Use assert() to check admissable values

Used in Examples (1)

LoveHateDynamics

BusinessSimulation.Examples

Romeo and Juliet model as introduced by Strogatz

Used in Components (12)

	AccumulatedPerformance BusinessSimulation.Examples.SoftwareReleaseProject Weighted average performance per period
	SimpleInformationLevel BusinessSimulation.CausalLoop Information level for CLD-like modeling
	HinesCoflow BusinessSimulation.Stocks Accounting for changes in average quality of a stock as new entries with different characteristic flow in
	Smooth BusinessSimulation.Converters.DiscreteDelay First-order exponential smooth
	AsymmetricSmooth BusinessSimulation.Converters.DiscreteDelay A smooth with different delay times for positive and negative changes
	AccumulationFunction BusinessSimulation.Converters Determing the time value of money for an investment of 1
	FinancialReporting BusinessSimulation.MoleculesOfStructure.InformationProcessing Periodic reporting of a financial flow for the past accounting period
	PresentValue BusinessSimulation.MoleculesOfStructure.InformationProcessing Calculates the present value of a stream of cash flows
	ExperienceCurve BusinessSimulation.MoleculesOfStructure.Blocks Unit cost degression due to gaining experience
	Account BusinessSimulation.MoleculesOfStructure.Incubators Basic model of an account with optional interest
	Collector BusinessSimulation.MoleculesOfStructure.Incubators A reservoir that aggregates multiple stock ports
	Reservoir BusinessSimulation.MoleculesOfStructure.Transceivers A single stock drained by an outflow at a given rate