isTriangularNumber

Test if a value is a triangular number.

Triangular numbers can be computed using the following formula

for n >= 0.

By analogy with the square root of x, one can define the positive triangular root of x such that T_n = x

Accordingly, an integer x is a triangular number if and only if 8x+1 is a square number.

Installation

npm install @stdlib/assert-is-triangular-number

Usage

var isTriangularNumber = require( '@stdlib/assert-is-triangular-number' );

isTriangularNumber( value )

Tests if a value is a triangular number.

var Number = require( '@stdlib/number-ctor' );

var bool = isTriangularNumber( 36.0 );
// returns true

bool = isTriangularNumber( new Number( 36.0 ) );
// returns true

bool = isTriangularNumber( 3.14 );
// returns false

bool = isTriangularNumber( -5.0 );
// returns false

bool = isTriangularNumber( NaN );
// returns false

bool = isTriangularNumber( null );
// returns false

isTriangularNumber.isPrimitive( value )

Tests if a value is a primitive triangular number.

var Number = require( '@stdlib/number-ctor' );

var bool = isTriangularNumber.isPrimitive( 36.0 );
// returns true

bool = isTriangularNumber.isPrimitive( new Number( 36.0 ) );
// returns false

isTriangularNumber.isObject( value )

Tests if a value is a Number object having a value which is a triangular number.

var Number = require( '@stdlib/number-ctor' );

var bool = isTriangularNumber.isObject( 36.0 );
// returns false

bool = isTriangularNumber.isObject( new Number( 36.0 ) );
// returns true

Notes

• Return values are not reliable for numbers greater than 1125899906842624.

Examples

var Number = require( '@stdlib/number-ctor' );
var isTriangularNumber = require( '@stdlib/assert-is-triangular-number' );

var bool = isTriangularNumber( 36.0 );
// returns true

bool = isTriangularNumber( new Number( 36.0 ) );
// returns true

bool = isTriangularNumber( 0.0 );
// returns true

bool = isTriangularNumber( 1.0 );
// returns true

bool = isTriangularNumber( 3.14 );
// returns false

bool = isTriangularNumber( -5.0 );
// returns false

bool = isTriangularNumber( NaN );
// returns false

bool = isTriangularNumber( '0.5' );
// returns false

bool = isTriangularNumber( null );
// returns false

See Also

• @stdlib/assert-is-integer: test if a value is a number having an integer value.
• @stdlib/assert-is-number: test if a value is a number.
• @stdlib/assert-is-square-number: test if a value is a square number.
• @stdlib/assert-is-square-triangular-number: test if a value is a square triangular number.

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.