Generates random data from the gamma probability distribution. There are two forms.

Syntax

RND = GammaRnd(a, b, Rows, Cols, Seed, State)

RND = GammaRnd(a, b, Seed, State)

Arguments

Name

Description

a

Shape parameter. A scalar, vector or matrix of positive values. See Comments.

b

Scale parameter. A scalar, vector or matrix of positive values. See Comments.

Rows

(optional)

Number of output rows. A positive integer. Only valid when a and b are scalars.

Cols

(optional)

Number of output columns. A positive integer. Only valid when a and b are scalars.

Seed

(optional)

The seed to initialize the random number generator. An integer. See Comments below.

State

(optional)

Set to "discard" if the state of the pseudo random number is not to be retained for future use. The default is "retain".

Outputs

Name

Description

RND

Random numbers from the gamma distribution. Its dimensions are determined by the input arguments. See Comments below.

Example 1

Generate two random numbers from the gamma distribution with (a, b) pairs of (2, 5) and (4, 3) respectively, with a random seed of 2003

Syntax

rnd = GammaRnd([2,4],[5,3],2003)

Results

rnd = 7.0869    9.7002

Example 2

Generate a 1x4 vector of random numbers from the gamma distribution with a = 2, b = 5 and a random seed 2003.

Syntax

rnd = GammaRnd(2,5,1,4,2003)

Results

rnd = 7.0869    8.0835    9.0355    10.602

Comments

The form of distribution function is such that the mean is a*b.

a and b must be the same size.

If the optional size inputs are omitted, the size of the output is solely determined by the size of the two inputs a and b. Each entry in the output uses the corresponding entries in the two inputs.

If the optional size inputs are provided, both must be supplied. In that case, a and b must be scalars and the size of the output is determined by Rows and Cols. That is, the inputs a and b are used for each element of the output.

The Seed can be any number. Using a seed allows a random sequence to be repeated.

See Also:

GammaCDF

GammaInvCDF

GammaPDF

Probability Distributions