iterTriangularSeq

Create an iterator which generates a sequence of triangular numbers.

The triangular numbers are the integer sequence

starting at the 0th triangular number.

Triangular numbers are given by the following explicit formulas

where the last formula corresponds to a binomial coefficient, representing the number of distinct pairs that can be selected from n+1 items.

Installation

npm install @stdlib/math-iter-sequences-triangular

Usage

var iterTriangularSeq = require( '@stdlib/math-iter-sequences-triangular' );

iterTriangularSeq( [options] )

Returns an iterator which generates a sequence of triangular numbers.

var it = iterTriangularSeq();
// returns <Object>

var v = it.next().value;
// returns 0

v = it.next().value;
// returns 1

v = it.next().value;
// returns 3

v = it.next().value;
// returns 6

v = it.next().value;
// returns 10

// ...

The returned iterator protocol-compliant object has the following properties:

• next: function which returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to a value property and a done property having a boolean value indicating whether the iterator is finished.
• return: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.

The function supports the following options:

• iter: number of iterations. Default: 134217727.

By default, the function returns a finite iterator to avoid exceeding the maximum safe double-precision floating-point integer. To adjust the number of iterations, set the iter option.

var opts = {
    'iter': 2
};
var it = iterTriangularSeq( opts );
// returns <Object>

var v = it.next().value;
// returns 0

v = it.next().value;
// returns 1

var bool = it.next().done;
// returns true

Notes

• If an environment supports Symbol.iterator, the returned iterator is iterable.

Examples

var iterTriangularSeq = require( '@stdlib/math-iter-sequences-triangular' );

// Create an iterator:
var opts = {
    'iter': 100
};
var it = iterTriangularSeq( opts );

// Perform manual iteration...
var v;
while ( true ) {
    v = it.next();
    if ( v.done ) {
        break;
    }
    console.log( v.value );
}

See Also

• @stdlib/math-iter/sequences/squared-triangular: create an iterator which generates a sequence of squared triangular numbers.

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

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.