# Stochastic Modeling

A
model can be stochastic as well as deterministic. There are many
different ways to incorporate nondeterminism into a model. For example,
you can assign a randomly generated time value to a transition, event
rate, or delay operation. Or a random value or its derivative can be
used to determine a message destination address, evaluate a guard
expression, or otherwise impact the model behavior.

#### Random serialization of simultaneous events

There
is also a case when the model can have stochastic behavior, even if you
do not specify it explicitly using randomly generated values: this is
random serialization of simultaneous events. If several events are
available at the same time, AnyLogic can make nondeterministic choice
with equal probability for each event. Otherwise, the model behavior is
deterministic and 100% reproducible irrespective of the seed of the
random number generator.

To turn random serialization on

- In the
Projects
view, select the experiment you are currently working with.
- Go to the
Randomness
section of the
Properties
view.
- Select the optionRandom
for the parameter
Selection mode for simultaneous events.

To enable conducting complicated experiments over stochastic models, AnyLogic supports
replication mechanism. Please refer to the following help topics for more information:

Optimizing stochastic models