# mean

Average or mean value of fixed-point array

## Syntax

`c`

= mean(`a`

)

`c`

= mean(`a`

,`dim`

)

## Description

`c`

= mean(`a`

)

computes
the mean value of the fixed-point array `a`

along
its first nonsingleton dimension.

`c`

= mean(`a`

,`dim`

)

computes
the mean value of the fixed-point array `a`

along
dimension `dim`

. `dim`

must
be a positive, real-valued integer with a power-of-two slope and a
bias of 0.

The input to the `mean`

function must be a
real-valued fixed-point array.

The fixed-point output array `c`

has
the same `numerictype`

properties as the fixed-point
input array `a`

. If the input, `a`

,
has a local `fimath`

, then it is used for intermediate
calculations. The output, `c`

, is always
associated with the default `fimath`

.

When `a`

is an empty fixed-point array
(value = `[]`

), the value of the output array is
zero.

## Examples

Compute the mean value along the first dimension (rows) of a
fixed-point array.

x = fi([0 1 2; 3 4 5], 1, 32);
% x is a signed FI object with a 32-bit word length
% and a best-precision fraction length of 28-bits
mx1 = mean(x,1)

Compute the mean value along the second dimension (columns)
of a fixed-point array.

x = fi([0 1 2; 3 4 5], 1, 32);
% x is a signed FI object with a 32-bit word length
% and a best-precision fraction length of 28 bits
mx2 = mean(x,2)

## Algorithms

The general equation for computing the `mean`

of
an array `a`

, across dimension `dim`

is:

Because `size(a,dim)`

is always a positive
integer, the algorithm casts `size(a,dim)`

to an
unsigned 32-bit `fi`

object with a fraction length
of zero (`SizeA`

). The algorithm then computes the
mean of `a`

according to the following equation,
where `Tx`

represents the `numerictype`

properties
of the fixed-point input array `a`

:

c = Tx.divide(sum(a,dim), SizeA)

## Extended Capabilities

### C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

#### Introduced in R2010a