## ALL All True Function

Section: Elementary Functions

### Usage

Reduces a logical array along a given dimension by testing for all logical 1s. The general syntax for its use isy = all(x,d)

where `x`

is an `n`

-dimensions array of `logical`

type.
The output is of `logical`

type. The argument `d`

is
optional, and denotes the dimension along which to operate.
The output `y`

is the same size as `x`

, except that it is
singular along the operated direction. So, for example,
if `x`

is a `3 x 3 x 4`

array, and we `all`

operation along
dimension `d=2`

, then the output is of size `3 x 1 x 4`

.

### Function Internals

The output is computed via

If `d`

is omitted, then the minimum is taken over all elements of
`x`

.

### Example

The following piece of code demonstrates various uses of the`all`

function
--> A = [1,0,0;1,0,0;0,0,1] A = 1 0 0 1 0 0 0 0 1

We start by calling `all`

without a dimension argument, in which
case it defaults to testing all values of `A`

--> all(A) ans = 0 0 0

The `all`

function is useful in expressions also.

--> all(A>=0) ans = 1 1 1

Next, we apply the `all`

operation along the rows.

--> all(A,2) ans = 0 0 0