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.
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
valueproperty and adoneproperty having abooleanvalue 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 );
}