@stdlib/random-strided-tools-unary-factory

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unaryFactory

Create a factory function for filling strided arrays with pseudorandom values drawn from a unary PRNG.

Installation

npm install @stdlib/random-strided-tools-unary-factory

Usage

var unaryFactory = require( '@stdlib/random-strided-tools-unary-factory' );

unaryFactory( prng )

Returns a factory function for filling strided arrays with pseudorandom values drawn from a unary PRNG.

var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

The function has the following parameters:

• prng: unary pseudorandom number generator.

---

factory( [options] )

Returns a function for filling strided arrays with pseudorandom values drawn from a unary PRNG.

var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

The function has the following parameters:

• 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.

To use a custom PRNG as the underlying source of uniformly distributed pseudorandom numbers, set the prng option.

var Float64Array = require( '@stdlib/array-float64' );
var minstd = require( '@stdlib/random-base-minstd' );
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var opts = {
    'prng': minstd.normalized
};

var random = factory( opts );
// returns <Function>

var out = new Float64Array( 10 );
random( out.length, [ 2.0 ], 0, out, 1 );

To seed the underlying pseudorandom number generator, set the seed option.

var Float64Array = require( '@stdlib/array-float64' );
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var opts = {
    'seed': 12345
};

var random = factory( opts );
// returns <Function>

var out = new Float64Array( 10 );
random( out.length, [ 2.0 ], 0, out, 1 );

---

random( N, param1, sp1, out, so )

Fills a strided array with pseudorandom values drawn from a unary PRNG.

var Float64Array = require( '@stdlib/array-float64' );
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

var out = new Float64Array( 10 );
// returns <Float64Array>

var v = random( out.length, [ 2.0 ], 0, out, 1 );
// returns <Float64Array>

The function has the following parameters:

• N: number of indexed elements.
• param1: PRNG parameter.
• sp1: index increment for param1.
• out: output array.
• so: index increment for out.

The N and stride parameters determine which strided array elements are accessed at runtime. For example, to access every other value in out,

var Float64Array = require( '@stdlib/array-float64' );
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

var out = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];

random( 3, [ 2.0 ], 0, out, 2 );

Note that indexing is relative to the first index. To introduce an offset, use typed array views.

var Float64Array = require( '@stdlib/array-float64' );
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

// Initial array:
var param0 = new Float64Array( [ 5.0, 5.0, 5.0, 5.0, 5.0, 5.0 ] );

// Create offset view:
var param1 = new Float64Array( param0.buffer, param0.BYTES_PER_ELEMENT*3 ); // start at 4th element

// Create an output array:
var out = new Float64Array( 3 );

// Fill the output array:
random( out.length, param1, -1, out, 1 );

random.ndarray( N, param1, sp1, op1, out, so, oo )

Fills a strided array with pseudorandom values drawn from a unary PRNG using alternative indexing semantics.

var Float64Array = require( '@stdlib/array-float64' );
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

var out = new Float64Array( 10 );
// returns <Float64Array>

var v = random.ndarray( out.length, [ 2.0 ], 0, 0, out, 1, 0 );
// returns <Float64Array>

The function has the following additional parameters:

• op1: starting index for param1.
• oo: starting index for out.

While typed array views mandate a view offset based on the underlying buffer, the offset parameters support indexing semantics based on starting indices. For example, to access every other value in out starting from the second value,

var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

var out = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];

random.ndarray( 3, [ 2.0 ], 0, 0, out, 2, 1 );

---

random.PRNG

The underlying pseudorandom number generator.

var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

var prng = random.PRNG;
// returns <Function>

random.seed

The value used to seed the underlying pseudorandom number generator.

var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

var seed = random.seed;
// returns <Uint32Array>

If the factory function is provided a PRNG for uniformly distributed numbers, the associated property value on the returned function is null.

var minstd = require( '@stdlib/random-base-minstd-shuffle' ).normalized;
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory({
    'prng': minstd
});
// returns <Function>

var seed = random.seed;
// returns null

random.seedLength

Length of underlying pseudorandom number generator seed.

var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

var len = random.seedLength;
// returns <number>

If the factory function is provided a PRNG for uniformly distributed numbers, the associated property value on the returned function is null.

var minstd = require( '@stdlib/random-base-minstd-shuffle' ).normalized;
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory({
    'prng': minstd
});
// returns <Function>

var len = random.seedLength;
// returns null

random.state

Writable property for getting and setting the underlying pseudorandom number generator state.

var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

var state = random.state;
// returns <Uint32Array>

If the factory function is provided a PRNG for uniformly distributed numbers, the associated property value on the returned function is null.

var minstd = require( '@stdlib/random-base-minstd-shuffle' ).normalized;
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory({
    'prng': minstd
});
// returns <Function>

var state = random.state;
// returns null

random.stateLength

Length of underlying pseudorandom number generator state.

var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

var len = random.stateLength;
// returns <number>

If the factory function is provided a PRNG for uniformly distributed numbers, the associated property value on the returned function is null.

var minstd = require( '@stdlib/random-base-minstd-shuffle' ).normalized;
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory({
    'prng': minstd
});
// returns <Function>

var len = random.stateLength;
// returns null

random.byteLength

Size (in bytes) of underlying pseudorandom number generator state.

var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory();
// returns <Function>

var sz = random.byteLength;
// returns <number>

If the factory function is provided a PRNG for uniformly distributed numbers, the associated property value on the returned function is null.

var minstd = require( '@stdlib/random-base-minstd-shuffle' ).normalized;
var exponential = require( '@stdlib/random-base-exponential' );

var factory = unaryFactory( exponential );
// returns <Function>

var random = factory({
    'prng': minstd
});
// returns <Function>

var sz = random.byteLength;
// returns null

---

Examples

var exponential = require( '@stdlib/random-base-exponential' );
var zeros = require( '@stdlib/array-zeros' );
var zeroTo = require( '@stdlib/array-zero-to' );
var logEach = require( '@stdlib/console-log-each' );
var unaryFactory = require( '@stdlib/random-strided-tools-unary-factory' );

// Create a PRNG factory function:
var factory = unaryFactory( exponential );
// returns <Function>

// Specify a PRNG seed:
var opts = {
    'seed': 1234
};

// Create a function for filling strided arrays:
var rand1 = factory( opts );
// returns <Function>

// Create an array:
var x1 = zeros( 10, 'float64' );

// Fill the array with pseudorandom numbers:
rand1( x1.length, [ 2.0 ], 0, x1, 1 );

// Create another function for filling strided arrays:
var rand2 = factory( opts );
// returns <Function>

// Create a second array:
var x2 = zeros( 10, 'generic' );

// Fill the array with the same pseudorandom numbers:
rand2( x2.length, [ 2.0 ], 0, x2, 1 );

// Create a list of indices:
var idx = zeroTo( x1.length, 'generic' );

// Print the array contents:
logEach( 'x1[%d] = %.2f; x2[%d] = %.2f', idx, x1, idx, x2 );

---

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

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License

See LICENSE.

Copyright

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