gampdf (Statistics Toolbox)

Gamma probability density function (pdf)

Syntax

```
Y = gampdf(X,A,B)
```

Description

gampdf(X,A,B) computes the gamma pdf at each of the values in X using the corresponding parameters in A and B. Vector or matrix inputs for X, A, and B must all be the same size. A scalar input is expanded to a constant matrix with the same dimensions as the other inputs. The parameters in A and B must all be positive, and the values in X must lie on the interval [0 ).

The gamma pdf is

The gamma probability density function is useful in reliability models of lifetimes. The gamma distribution is more flexible than the exponential distribution in that the probability of a product surviving an additional period may depend on its current age. The exponential and ² functions are special cases of the gamma function.

Examples

The exponential distribution is a special case of the gamma distribution.

mu = 1:5;
y = gampdf(1,1,mu)
y =
    0.3679    0.3033    0.2388    0.1947    0.1637
y1 = exppdf(1,mu)
y1 =
    0.3679    0.3033    0.2388    0.1947    0.1637

gamlike gamrnd