# unaryFactory
> Create a factory function for generating pseudorandom values drawn from a unary PRNG.
## Usage
```javascript
var unaryFactory = require( '@stdlib/random/array/tools/unary-factory' );
```
#### unaryFactory( prng, dtypes, dtype )
Returns a factory function for generating pseudorandom values drawn from a unary PRNG.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, 'float64' );
// returns
```
The function has the following parameters:
- **prng**: unary pseudorandom number generator.
- **dtypes**: list of supported output data types.
- **dtype**: default output array data type.
* * *
#### factory( \[param1, ]\[options] )
Returns a function for generating pseudorandom values drawn from a unary PRNG.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory();
// returns
```
The function has the following parameters:
- **param1**: PRNG parameter. If provided a PRNG parameter, the function returns a partially applied function for creating arrays, which can be useful when wanting to pass around a parameterized function for array creation.
- **options**: function options.
The function supports the following options:
- **prng**: pseudorandom number generator which generates uniformly distributed pseudorandom numbers.
- **seed**: pseudorandom value generator seed.
- **state**: pseudorandom value generator state.
- **copy**: boolean indicating whether to copy a provided pseudorandom value generator state.
- **dtype**: default output array data type. Setting this option overrides the default output array data type provided to the parent function.
* * *
### Full Arity
#### random( len, param1\[, options] )
Returns an array of pseudorandom values drawn from a unary PRNG.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory();
// returns
var v = random( 10, 2.0 );
// returns
```
The function has the following parameters:
- **len**: output array length.
- **param1**: PRNG parameter.
- **options**: function options.
The function accepts the following options:
- **dtype**: output array data type. Setting this option overrides the default output array data type.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory();
// returns
var v = random( 10, 2.0, {
'dtype': 'float32'
});
// returns
```
#### random.assign( param1, out )
Fills an array with pseudorandom values drawn from a unary PRNG.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var zeros = require( '@stdlib/array/zeros' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory();
// returns
var out = zeros( 10, 'float64' );
// returns
var v = random.assign( 2.0, out );
// returns
var bool = ( out === v );
// returns true
```
The method has the following parameters:
- **param1**: PRNG parameter.
- **out**: output array.
### Partial Application
#### random( len\[, options] )
Returns an array of pseudorandom values drawn from a unary PRNG.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory( 2.0 );
// returns
var v = random( 10 );
// returns
v = random( 10 );
// returns
```
The function has the following parameters:
- **len**: output array length.
- **options**: function options.
The function accepts the following options:
- **dtype**: output array data type. Setting this option overrides the default output array data type.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory( 2.0 );
// returns
var v = random( 10, {
'dtype': 'float32'
});
// returns
v = random( 10, {
'dtype': 'generic'
});
// returns [...]
```
#### random.assign( out )
Fills an array with pseudorandom values drawn from a unary PRNG.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var zeros = require( '@stdlib/array/zeros' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory( 2.0 );
// returns
var out = zeros( 10, 'float64' );
// returns
var v = random.assign( out );
// returns
var bool = ( out === v );
// returns true
```
The method has the following parameters:
- **out**: output array.
* * *
#### random.PRNG
The underlying pseudorandom number generator.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory();
// returns
var prng = random.PRNG;
// returns
```
#### random.seed
The value used to seed the underlying pseudorandom number generator.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory();
// returns
var seed = random.seed;
// returns
```
If the `factory` function is provided a PRNG for uniformly distributed numbers, the associated property value on the returned function is `null`.
```javascript
var minstd = require( '@stdlib/random/base/minstd-shuffle' ).normalized;
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory({
'prng': minstd
});
// returns
var seed = random.seed;
// returns null
```
#### random.seedLength
Length of underlying pseudorandom number generator seed.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory();
// returns
var len = random.seedLength;
// returns
```
If the `factory` function is provided a PRNG for uniformly distributed numbers, the associated property value on the returned function is `null`.
```javascript
var minstd = require( '@stdlib/random/base/minstd-shuffle' ).normalized;
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory({
'prng': minstd
});
// returns
var len = random.seedLength;
// returns null
```
#### random.state
Writable property for getting and setting the underlying pseudorandom number generator state.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory();
// returns
var state = random.state;
// returns
```
If the `factory` function is provided a PRNG for uniformly distributed numbers, the associated property value on the returned function is `null`.
```javascript
var minstd = require( '@stdlib/random/base/minstd-shuffle' ).normalized;
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory({
'prng': minstd
});
// returns
var state = random.state;
// returns null
```
#### random.stateLength
Length of underlying pseudorandom number generator state.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory();
// returns
var len = random.stateLength;
// returns
```
If the `factory` function is provided a PRNG for uniformly distributed numbers, the associated property value on the returned function is `null`.
```javascript
var minstd = require( '@stdlib/random/base/minstd-shuffle' ).normalized;
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory({
'prng': minstd
});
// returns
var len = random.stateLength;
// returns null
```
#### random.byteLength
Size (in bytes) of underlying pseudorandom number generator state.
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory();
// returns
var sz = random.byteLength;
// returns
```
If the `factory` function is provided a PRNG for uniformly distributed numbers, the associated property value on the returned function is `null`.
```javascript
var minstd = require( '@stdlib/random/base/minstd-shuffle' ).normalized;
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = [ 'float64', 'float32', 'generic' ];
var factory = unaryFactory( exponential, dtypes, dtypes[ 0 ] );
// returns
var random = factory({
'prng': minstd
});
// returns
var sz = random.byteLength;
// returns null
```
* * *
## Examples
```javascript
var exponential = require( '@stdlib/random/base/exponential' );
var dtypes = require( '@stdlib/array/dtypes' );
var unaryFactory = require( '@stdlib/random/array/tools/unary-factory' );
var dt = dtypes( 'real_floating_point_and_generic' );
var factory = unaryFactory( exponential, dt, 'float64' );
// returns
var random = factory();
// returns
var x = random( 10, 2.0 );
// returns
x = random( 10, 2.0, {
'dtype': 'float32'
});
// returns
x = random( 10, 2.0, {
'dtype': 'generic'
});
// returns [...]
```