102 lines
2.0 KiB
Markdown
102 lines
2.0 KiB
Markdown
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@license Apache-2.0
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Copyright (c) 2018 The Stdlib Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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# Lucas Number
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> Maximum safe [Lucas number][lucas-number] when stored in [double-precision floating-point][ieee754] format.
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<section class="usage">
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## Usage
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```javascript
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var FLOAT64_MAX_SAFE_LUCAS = require( '@stdlib/constants/float64/max-safe-lucas' );
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```
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#### FLOAT64_MAX_SAFE_LUCAS
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The maximum [safe][safe-integers] [Lucas number][lucas-number] when stored in [double-precision floating-point][ieee754] format.
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```javascript
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var bool = ( FLOAT64_MAX_SAFE_LUCAS === 7639424778862807 );
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// returns true
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```
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</section>
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<!-- /.usage -->
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<section class="examples">
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## Examples
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<!-- eslint no-undef: "error" -->
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```javascript
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var FLOAT64_MAX_SAFE_LUCAS = require( '@stdlib/constants/float64/max-safe-lucas' );
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var v;
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var i;
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function lucas( n ) {
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var a;
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var b;
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var c;
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var i;
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a = 2;
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if ( n === 0 ) {
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return a;
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}
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b = 1;
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for ( i = 2; i <= n; i++ ) {
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c = a + b;
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a = b;
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b = c;
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}
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return b;
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}
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for ( i = 0; i < 100; i++ ) {
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v = lucas( i );
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if ( v > FLOAT64_MAX_SAFE_LUCAS ) {
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console.log( 'Unsafe: %d', v );
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} else {
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console.log( 'Safe: %d', v );
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}
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}
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```
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</section>
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<!-- /.examples -->
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<section class="links">
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[safe-integers]: http://www.2ality.com/2013/10/safe-integers.html
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[lucas-number]: https://en.wikipedia.org/wiki/Lucas_number
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[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
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</section>
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<!-- /.links -->
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