102 lines
2.5 KiB
Markdown
102 lines
2.5 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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# sincospi
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> Simultaneously compute the [sine][@stdlib/math/base/special/sin] and [cosine][@stdlib/math/base/special/cos] of a number times [π][@stdlib/constants/float64/pi].
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<section class="usage">
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## Usage
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```javascript
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var sincospi = require( '@stdlib/math/base/special/sincospi' );
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```
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#### sincospi( \[out,] x )
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Simultaneously computes the [sine][@stdlib/math/base/special/sin] and [cosine][@stdlib/math/base/special/cos] of a `number` times [π][@stdlib/constants/float64/pi] more accurately than `sincos(pi*x)`, especially for large `x`.
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```javascript
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var v = sincospi( 0.0 );
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// returns [ 0.0, 1.0 ]
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v = sincospi( 0.5 );
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// returns [ 1.0, 0.0 ]
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v = sincospi( 0.1 );
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// returns [ ~0.309, ~0.951 ]
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v = sincospi( NaN );
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// returns [ NaN, NaN ]
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```
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By default, the function returns a two-element `array` containing `sin(πx)` and `cos(πx)`. To avoid extra memory allocation, the function supports providing an output (destination) object.
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```javascript
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var Float64Array = require( '@stdlib/array/float64' );
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var out = new Float64Array( 2 );
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var v = sincospi( out, 0.0 );
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// returns <Float64Array>[ 0.0, 1.0 ]
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var bool = ( v === out );
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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 linspace = require( '@stdlib/array/linspace' );
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var sincospi = require( '@stdlib/math/base/special/sincospi' );
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var x = linspace( 0.0, 2.0, 101 );
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var i;
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for ( i = 0; i < x.length; i++ ) {
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console.log( sincospi( x[ i ] ) );
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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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[@stdlib/math/base/special/sin]: https://www.npmjs.com/package/@stdlib/math/tree/main/base/special/sin
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[@stdlib/math/base/special/cos]: https://www.npmjs.com/package/@stdlib/math/tree/main/base/special/cos
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[@stdlib/constants/float64/pi]: https://www.npmjs.com/package/@stdlib/constants-float64-pi
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</section>
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<!-- /.links -->
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