iterNegaLucasSeq

Create an iterator which generates a negaLucas sequence.

The negaLucas numbers are the integer sequence

The sequence is defined by the recurrence relation

which yields

with seed values L_0 = 2 and L_{-1} = -1.

Installation

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

Usage

var iterNegaLucasSeq = require( '@stdlib/math-iter-sequences-negalucas' );

iterNegaLucasSeq( [options] )

Returns an iterator which generates a negaLucas sequence.

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

var v = it.next().value;
// returns 2

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

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

// ...

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: 77.

The returned iterator can only generate the first 77 negaLucas numbers, as larger negaLucas numbers cannot be safely represented in double-precision floating-point format. By default, the function returns an iterator which generates all 77 numbers. To limit the number of iterations, set the iter option.

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

var v = it.next().value;
// returns 2

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 iterNegaLucasSeq = require( '@stdlib/math-iter-sequences-negalucas' );

// Create an iterator:
var it = iterNegaLucasSeq();

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

See Also

• @stdlib/math-base/special/negalucas: compute the nth negaLucas number.
• @stdlib/math-iter/sequences/lucas: create an iterator which generates a Lucas sequence.
• @stdlib/math-iter/sequences/negafibonacci: create an iterator which generates a negaFibonacci sequence.

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.