time-to-botec

README.md (5755B)

---

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 # iterNegaLucasSeq
 
 > Create an iterator which generates a [negaLucas sequence][lucas-number].
 
 <!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
 
 <section class="intro">
 
 The [negaLucas numbers][lucas-number] are the integer sequence
 
 <!-- <equation class="equation" label="eq:negalucas_sequence" align="center" raw="2, -1, 3, -4, 7, -11, 18, -29, 47, -76, 123, -199, 322, \ldots" alt="NegaLucas sequence"> -->
 
 <div class="equation" align="center" data-raw-text="2, -1, 3, -4, 7, -11, 18, -29, 47, -76, 123, -199, 322, \ldots" data-equation="eq:negalucas_sequence">
     <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@aa77a2f6e76d2e9da5b49bffa45ee5167d6c16e1/lib/node_modules/@stdlib/math/iter/sequences/negalucas/docs/img/equation_negalucas_sequence.svg" alt="NegaLucas sequence">
     <br>
 </div>
 
 <!-- </equation> -->
 
 The sequence is defined by the recurrence relation
 
 <!-- <equation class="equation" label="eq:negalucas_recurrence_relation" align="center" raw="L_{n-2} = L_{n} - L_{n-1}" alt="NegaLucas sequence recurrence relation"> -->
 
 <div class="equation" align="center" data-raw-text="L_{n-2} = L_{n} - L_{n-1}" data-equation="eq:negalucas_recurrence_relation">
     <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@aa77a2f6e76d2e9da5b49bffa45ee5167d6c16e1/lib/node_modules/@stdlib/math/iter/sequences/negalucas/docs/img/equation_negalucas_recurrence_relation.svg" alt="NegaLucas sequence recurrence relation">
     <br>
 </div>
 
 <!-- </equation> -->
 
 which yields
 
 <!-- <equation class="equation" label="eq:negalucas_lucas" align="center" raw="L_{-n} = (-1)^{n} L_n" alt="NegaLucas relationship to Lucas numbers"> -->
 
 <div class="equation" align="center" data-raw-text="L_{-n} = (-1)^{n} L_n" data-equation="eq:negalucas_lucas">
     <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@aa77a2f6e76d2e9da5b49bffa45ee5167d6c16e1/lib/node_modules/@stdlib/math/iter/sequences/negalucas/docs/img/equation_negalucas_lucas.svg" alt="NegaLucas relationship to Lucas numbers">
     <br>
 </div>
 
 <!-- </equation> -->
 
 with seed values `L_0 = 2` and `L_{-1} = -1`.
 
 </section>
 
 <!-- /.intro -->
 
 <!-- Package usage documentation. -->
 
 <section class="usage">
 
 ## Usage
 
 ```javascript
 var iterNegaLucasSeq = require( '@stdlib/math/iter/sequences/negalucas' );
 ```
 
 #### iterNegaLucasSeq( \[options] )
 
 Returns an iterator which generates a [negaLucas sequence][lucas-number].
 
 ```javascript
 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][lucas-number], as larger [negaLucas numbers][lucas-number] cannot be safely represented in [double-precision floating-point format][ieee754]. By default, the function returns an iterator which generates all `77` numbers. To limit the number of iterations, set the `iter` option.
 
 ```javascript
 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
 ```
 
 </section>
 
 <!-- /.usage -->
 
 <!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
 
 <section class="notes">
 
 ## Notes
 
 -   If an environment supports `Symbol.iterator`, the returned iterator is iterable.
 
 </section>
 
 <!-- /.notes -->
 
 <!-- Package usage examples. -->
 
 <section class="examples">
 
 ## Examples
 
 <!-- eslint no-undef: "error" -->
 
 ```javascript
 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 );
 }
 ```
 
 </section>
 
 <!-- /.examples -->
 
 <!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
 
 <section class="references">
 
 </section>
 
 <!-- /.references -->
 
 <!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
 
 <section class="links">
 
 [lucas-number]: https://en.wikipedia.org/wiki/Lucas_number
 
 [ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
 
 </section>
 
 <!-- /.links -->