Random
A random variable (RandomVariable) is a function that maps a probability space to a real number. A random variable uses a RandomIfc to provide the underlying mapping to a real number via the value() method.
To construct a RandomVariable the user must provide an instance of a class that implements the RandomIfc interface as the initial random source. This source is used to initialize the source of randomness for each replication.
WARNING: For efficiency, this class uses a direct reference to the supplied initial random source. It simply wraps the supplied object reference to a random source so that it can be utilized within the KSL model. Because of the direct reference to the random source, a change to the state of the random source will be reflected in the use of that instance within this class. Thus, mutating the state of the random source will also see those mutations reflected in the usage of this class. This may or not be what is expected by the client. For example, mutating the state of the initial random source during a replication may cause each replication to start with different initial conditions.
Using the randomSource property allows the user to change the source of randomness during a replication. The source of randomness during a replication is set to the reference of the initial random source prior to running any replications. This ensures that each replication uses the same random source during the replication, unless the random source is changed during a replication. However, the user may use the randomSource property to immediately change the source of randomness during the replication. This change is in effect only during the current replication. After each replication, the source of randomness is set back to the reference to the initial random source. This ensures that each replication starts off using the same random source. For this reason, the use of initialRandomSource property should be limited to before or after running a simulation experiment.
The initial source is used to set up the source used during the replication. If the client changes the reference to the initial source, this change does not become effective until the beginning of the next replication. In other words, the random source used during the replication is unaffected. However, the client might change the initial random source during a replication. If this occurs, the change happens but the replication will continue to use its current random source as defined by the randomSource property. The change in the initial random source does not really take effect until the beginning of the NEXT replication. Again, mutating the initial random source during a replication is generally a bad idea unless you really know what you are doing.
Changing the initial random source between experiments (simulation runs) is very common. For example, to set up an experiment that has different random characteristics the client can and should change the initial source of randomness (either by mutating the initial random source or by supplying a reference to a different initial random source).
To facilitate the synchronization of random number streams, the underlying random number stream will automatically be advanced to its next sub-stream after each replication. This occurs by default unless the resetNextSubStreamOption is set to false.
Properties
If true, the stream will automatically participate in having its stream advanced to the next sub-stream via stream managers
Tells the stream to start producing antithetic variates
Provides a reference to the underlying source of randomness to initialize each replication. Controls the underlying RandomIfc source for the element. This is the source to which each replication will be initialized. This is only used when the replication is initialized. Changing the reference has no effect during a replication.
The previous value from the sequence of values a double representing the last value in the sequence
Provides a reference to the underlying source of randomness during the replication. Controls the underlying RandomIfc source. This changes the source for the current replication only. The random variable will start to use this source immediately; however if a replication is started after this method is called, the random source will be reassigned to the initial random source before the next replication is executed. To change the random source for the entire experiment (all replications) use the initialRandomSource property
If true, the stream will automatically participate in having its stream reset to its start stream via stream managers
Functions
Positions the RNG at the beginning of its next substream
The resetStartStream method will position the RNG at the beginning of its stream. This is the same location in the stream as assigned when the RNG was created and initialized.
Resets the position of the RNG at the start of the current substream