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Fill a strided array with pseudorandom numbers drawn from a Rayleigh distribution.
To use in Observable,
rayleigh = require( 'https://cdn.jsdelivr.net/gh/stdlib-js/random-strided-rayleigh@umd/browser.js' )
To vendor stdlib functionality and avoid installing dependency trees for Node.js, you can use the UMD server build:
var rayleigh = require( 'path/to/vendor/umd/random-strided-rayleigh/index.js' )
To include the bundle in a webpage,
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/random-strided-rayleigh@umd/browser.js"></script>
If no recognized module system is present, access bundle contents via the global scope:
<script type="text/javascript">
(function () {
window.rayleigh;
})();
</script>
Fills a strided array with pseudorandom numbers drawn from a Rayleigh distribution.
var Float64Array = require( '@stdlib/array-float64' );
// Create an array:
var out = new Float64Array( 10 );
// Fill the array with pseudorandom numbers:
rayleigh( out.length, [ 2.0 ], 0, out, 1 );
The function has the following parameters:
- N: number of indexed elements.
- sigma: rate parameter.
- ss: index increment for
sigma
. - 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 out = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];
rayleigh( 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' );
// Initial array:
var sigma0 = new Float64Array( [ 2.0, 2.0, 2.0, 2.0, 2.0, 2.0 ] );
// Create offset view:
var sigma1 = new Float64Array( sigma0.buffer, sigma0.BYTES_PER_ELEMENT*3 ); // start at 4th element
// Create an output array:
var out = new Float64Array( 3 );
// Fill the output array:
rayleigh( out.length, sigma1, -1, out, 1 );
Fills a strided array with pseudorandom numbers drawn from a Rayleigh distribution using alternative indexing semantics.
var Float64Array = require( '@stdlib/array-float64' );
// Create an array:
var out = new Float64Array( 10 );
// Fill the array with pseudorandom numbers:
rayleigh.ndarray( out.length, [ 2.0 ], 0, 0, out, 1, 0 );
The function has the following additional parameters:
- os: starting index for
sigma
. - 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 out = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];
rayleigh.ndarray( 3, [ 2.0 ], 0, 0, out, 2, 1 );
Returns a function for filling strided arrays with pseudorandom numbers drawn from a Rayleigh distribution.
var Float64Array = require( '@stdlib/array-float64' );
var random = rayleigh.factory();
// returns <Function>
// Create an array:
var out = new Float64Array( 10 );
// Fill the array with pseudorandom numbers:
random( out.length, [ 2.0 ], 0, out, 1 );
The function accepts the following options
:
- prng: pseudorandom number generator for generating uniformly distributed pseudorandom numbers on the interval
[0,1)
. If provided, the function ignores both thestate
andseed
options. In order to seed the underlying pseudorandom number generator, one must seed the providedprng
(assuming the providedprng
is seedable). - seed: pseudorandom number generator seed.
- state: a
Uint32Array
containing pseudorandom number generator state. If provided, the function ignores theseed
option. - copy:
boolean
indicating whether to copy a provided pseudorandom number generator state. Setting this option tofalse
allows sharing state between two or more pseudorandom number generators. Setting this option totrue
ensures that an underlying generator has exclusive control over its internal state. Default:true
.
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 opts = {
'prng': minstd.normalized
};
var random = rayleigh.factory( opts );
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 opts = {
'seed': 12345
};
var random = rayleigh.factory( opts );
var out = new Float64Array( 10 );
random( out.length, [ 2.0 ], 0, out, 1 );
The underlying pseudorandom number generator.
var prng = rayleigh.PRNG;
// returns <Function>
The value used to seed the underlying pseudorandom number generator.
var seed = rayleigh.seed;
// returns <Uint32Array>
If the factory
method 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 random = rayleigh.factory({
'prng': minstd
});
// returns <Function>
var seed = random.seed;
// returns null
Length of underlying pseudorandom number generator seed.
var len = rayleigh.seedLength;
// returns <number>
If the factory
method 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 random = rayleigh.factory({
'prng': minstd
});
// returns <Function>
var len = random.seedLength;
// returns null
Writable property for getting and setting the underlying pseudorandom number generator state.
var state = rayleigh.state;
// returns <Uint32Array>
If the factory
method 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 random = rayleigh.factory({
'prng': minstd
});
// returns <Function>
var state = random.state;
// returns null
Length of underlying pseudorandom number generator state.
var len = rayleigh.stateLength;
// returns <number>
If the factory
method 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 random = rayleigh.factory({
'prng': minstd
});
// returns <Function>
var len = random.stateLength;
// returns null
Size (in bytes) of underlying pseudorandom number generator state.
var sz = rayleigh.byteLength;
// returns <number>
If the factory
method 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 random = rayleigh.factory({
'prng': minstd
});
// returns <Function>
var sz = random.byteLength;
// returns null
- If
N <= 0
, bothrayleigh
andrayleigh.ndarray
leave the output array unchanged. - Both
rayleigh
andrayleigh.ndarray
support array-like objects having getter and setter accessors for array element access.
<!DOCTYPE html>
<html lang="en">
<body>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-zeros@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-zero-to@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/console-log-each@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/random-strided-rayleigh@umd/browser.js"></script>
<script type="text/javascript">
(function () {
// Specify a PRNG seed:
var opts = {
'seed': 1234
};
// Create a seeded PRNG:
var rand1 = rayleigh.factory( opts );
// 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 = rayleigh.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 );
})();
</script>
</body>
</html>
@stdlib/random-base/rayleigh
: Rayleigh distributed pseudorandom numbers.@stdlib/random-array/rayleigh
: create an array containing pseudorandom numbers drawn from a Rayleigh distribution.
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For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.
See LICENSE.
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