@stdlib/math-iter-sequences-negafibonacci

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iterNegaFibonacciSeq

Create an iterator which generates a negaFibonacci sequence.

The negaFibonacci numbers are the integer sequence

-->

The sequence is defined by the recurrence relation

which yields

with seed values F_0 = 0 and F_{-1} = 1.

Installation

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

Usage

var iterNegaFibonacciSeq = require( '@stdlib/math-iter-sequences-negafibonacci' );

iterNegaFibonacciSeq( [options] )

Returns an iterator which generates a negaFibonacci sequence.

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

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

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

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

// ...

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: 79.

The returned iterator can only generate the first 79 negaFibonacci numbers, as larger Fibonacci numbers cannot be safely represented in double-precision floating-point format. By default, the function returns an iterator which generates all 79 numbers. To limit the number of iterations, set the iter option.

var opts = {
    'iter': 2
};
var it = iterNegaFibonacciSeq( 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 iterNegaFibonacciSeq = require( '@stdlib/math-iter-sequences-negafibonacci' );

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

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

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See Also

• @stdlib/math-base/special/negafibonacci: compute the nth negaFibonacci number.
• @stdlib/math-iter/sequences/fibonacci: create an iterator which generates a Fibonacci sequence.
• @stdlib/math-iter/sequences/nonfibonacci: create an iterator which generates a non-Fibonacci integer sequence.

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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

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License

See LICENSE.

Copyright

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