Create a readable stream for generating pseudorandom numbers drawn from a Kumaraswamy's double bounded distribution.
APACHE-2.0 License
Create a readable stream for generating pseudorandom numbers drawn from a Kumaraswamy's double bounded distribution.
npm install @stdlib/random-streams-kumaraswamy
Alternatively,
script
tag without installation and bundlers, use the ES Module available on the esm
branch (see README).deno
branch (see README for usage intructions).umd
branch (see README).The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
var randomStream = require( '@stdlib/random-streams-kumaraswamy' );
Returns a readable stream for generating pseudorandom numbers drawn from a Kumaraswamy's double bounded distribution with shape parameters a
and b
.
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
var iStream;
var stream;
function log( chunk, idx ) {
console.log( chunk.toString() );
if ( idx === 10 ) {
stream.destroy();
}
}
stream = randomStream( 2.0, 5.0 );
iStream = inspectStream( log );
stream.pipe( iStream );
The function accepts the following options
:
false
.Buffer
objects should be decoded to strings
. Default: null
.'\n'
.[0,1)
. If provided, the function ignores both the state
and seed
options. In order to seed the returned pseudorandom number generator stream, one must seed the provided prng
(assuming the provided prng
is seedable).Uint32Array
containing pseudorandom number generator state. If provided, the function ignores the seed
option.boolean
indicating whether to copy a provided pseudorandom number generator state. Setting this option to false
allows sharing state between two or more pseudorandom number generators and/or streams. Setting this option to true
ensures that a stream generator has exclusive control over its internal state. Default: true
.1e308
.To set stream options
,
var opts = {
'objectMode': true,
'encoding': 'utf8',
'highWaterMark': 64
};
var stream = randomStream( 2.0, 5.0, opts );
By default, the function returns a stream which can generate an infinite number of values (i.e., the stream will never end). To limit the number of generated pseudorandom numbers, set the iter
option.
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( chunk ) {
console.log( chunk.toString() );
}
var opts = {
'iter': 10
};
var stream = randomStream( 2.0, 1.0, opts );
var iStream = inspectStream( log );
stream.pipe( iStream );
By default, when not operating in objectMode, a returned stream delineates generated pseudorandom numbers using a newline character. To specify an alternative separator, set the sep
option.
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( chunk ) {
console.log( chunk.toString() );
}
var opts = {
'iter': 10,
'sep': ','
};
var stream = randomStream( 2.0, 1.0, opts );
var iStream = inspectStream( log );
stream.pipe( iStream );
To seed the underlying pseudorandom number generator, set the seed
option.
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( v ) {
console.log( v );
}
var opts = {
'objectMode': true,
'iter': 10,
'seed': 1234
};
var stream = randomStream( 2.0, 1.0, opts );
opts = {
'objectMode': true
};
var iStream = inspectStream( opts, log );
stream.pipe( iStream );
To return a readable stream with an underlying pseudorandom number generator having a specific initial state, set the state
option.
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( v ) {
console.log( v );
}
var opts1 = {
'objectMode': true,
'iter': 10
};
var stream = randomStream( 2.0, 5.0, opts1 );
var opts2 = {
'objectMode': true
};
var iStream = inspectStream( opts2, log );
// Stream pseudorandom numbers, thus progressing the underlying generator state:
stream.pipe( iStream );
// Create a new PRNG stream initialized to the last state of the previous stream:
var opts3 = {
'objectMode': true,
'iter': 10,
'state': stream.state
};
stream = randomStream( 2.0, 5.0, opts3 );
iStream = inspectStream( opts2, log );
// Stream pseudorandom numbers starting from the last state of the previous stream:
stream.pipe( iStream );
The underlying pseudorandom number generator.
var stream = randomStream( 2.0, 5.0 );
var prng = stream.PRNG;
// returns <Function>
The value used to seed the underlying pseudorandom number generator.
var stream = randomStream( 2.0, 5.0 );
var seed = stream.seed;
// returns <Uint32Array>
If provided a PRNG for uniformly distributed numbers, this value is null
.
var minstd = require( '@stdlib/random-base-minstd-shuffle' ).normalized;
var stream = randomStream( 2.0, 5.0, {
'prng': minstd
});
var seed = stream.seed;
// returns null
Length of underlying pseudorandom number generator seed.
var stream = randomStream( 2.0, 5.0 );
var len = stream.seedLength;
// returns <number>
If provided a PRNG for uniformly distributed numbers, this value is null
.
var minstd = require( '@stdlib/random-base-minstd-shuffle' ).normalized;
var stream = randomStream( 2.0, 5.0, {
'prng': minstd
});
var len = stream.seedLength;
// returns null
Writable property for getting and setting the underlying pseudorandom number generator state.
var stream = randomStream( 2.0, 5.0 );
var state = stream.state;
// returns <Uint32Array>
If provided a PRNG for uniformly distributed numbers, this value is null
.
var minstd = require( '@stdlib/random-base-minstd-shuffle' ).normalized;
var stream = randomStream( 2.0, 5.0, {
'prng': minstd
});
var state = stream.state;
// returns null
Length of underlying pseudorandom number generator state.
var stream = randomStream( 2.0, 5.0 );
var len = stream.stateLength;
// returns <number>
If provided a PRNG for uniformly distributed numbers, this value is null
.
var minstd = require( '@stdlib/random-base-minstd-shuffle' ).normalized;
var stream = randomStream( 2.0, 5.0, {
'prng': minstd
});
var len = stream.stateLength;
// returns null
Size (in bytes) of underlying pseudorandom number generator state.
var stream = randomStream( 2.0, 5.0 );
var sz = stream.byteLength;
// returns <number>
If provided a PRNG for uniformly distributed numbers, this value is null
.
var minstd = require( '@stdlib/random-base-minstd-shuffle' ).normalized;
var stream = randomStream( 2.0, 5.0, {
'prng': minstd
});
var sz = stream.byteLength;
// returns null
Returns a function
for creating readable streams which generate pseudorandom numbers drawn from a Kumaraswamy's double bounded distribution.
var opts = {
'objectMode': true,
'encoding': 'utf8',
'highWaterMark': 64
};
var createStream = randomStream.factory( opts );
If provided distribution parameters, the returned function returns readable streams which generate pseudorandom numbers drawn from the specified distribution.
var createStream = randomStream.factory( 2.0, 2.0 );
var stream1 = createStream();
var stream2 = createStream();
// ...
If not provided distribution parameters, the returned function requires that distribution parameters be provided at each invocation.
var createStream = randomStream.factory();
var stream1 = createStream( 2.0, 2.0 );
var stream2 = createStream( 2.0, 2.0 );
// ...
The method accepts the same options
as randomStream()
.
This method is a convenience function to create streams which always operate in objectMode.
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
function log( v ) {
console.log( v );
}
var opts = {
'iter': 10
};
var stream = randomStream.objectMode( 2.0, 2.0, opts );
opts = {
'objectMode': true
};
var iStream = inspectStream( opts, log );
stream.pipe( iStream );
This method accepts the same options
as randomStream()
; however, the method will always override the objectMode
option in options
.
In addition to the standard readable stream events, the following events are supported...
Emitted after internally generating siter
pseudorandom numbers.
var opts = {
'siter': 10 // emit the PRNG state every 10 pseudorandom numbers
};
var stream = randomStream( 2.0, 5.0, opts );
stream.on( 'state', onState );
function onState( state ) {
// Do something with the emitted state, such as save to file...
}
siter
option in conjunction with a state
event listener. Attempting to capture the underlying PRNG state after reading generated numbers is not likely to give expected results, as internal stream buffering will mean more values have been generated than have been read. Thus, the state returned by the state
property will likely reflect a future PRNG state from the perspective of downstream consumers.var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
var randomStream = require( '@stdlib/random-streams-kumaraswamy' );
function log( v ) {
console.log( v.toString() );
}
var opts = {
'objectMode': true,
'iter': 10
};
var stream = randomStream( 2.0, 2.0, opts );
opts = {
'objectMode': true
};
var iStream = inspectStream( opts, log );
stream.pipe( iStream );
To use as a general utility, install the CLI package globally
npm install -g @stdlib/random-streams-kumaraswamy-cli
Usage: random-kumaraswamy [options] <a> <b>
Options:
-h, --help Print this message.
-V, --version Print the package version.
--sep sep Separator used to join streamed data. Default: '\n'.
-n, --iter iterations Number of pseudorandom numbers.
--seed seed Pseudorandom number generator seed.
--state filepath Path to a file containing the pseudorandom number
generator state.
--snapshot filepath Output file path for saving the pseudorandom number
generator state upon exit.
$ random-kumaraswamy 2.0 1.0 -n 10 --seed 1234
@stdlib/random-base/kumaraswamy
: Kumaraswamy's double bounded distributed pseudorandom numbers.
@stdlib/random-iter/kumaraswamy
: create an iterator for generating pseudorandom numbers drawn from a Kumaraswamy's double bounded distribution.
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.
See LICENSE.
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