Exponential

Function for generating values from exponential distributions

Interface

exponential(r:real) : real

where r>0.0. Gives a drawing from a exponential distribution with intensity r.

Raises Exponential exception, if r<=0.0.

Characteristics

• Mean: 1/r
• Variance: 1/r^2

Density functions for exponential distributions:

Density functions for exponential distributions

Example

exponential(1.0/4.0)

Customers arrive at a post office for service. The time between two arrivals has a mean of 4 minutes. The inter-arrival time has an exponential distribution with parameter r=1/4.

Related pages

Random distribution functions