113 lines
2.5 KiB
Markdown
113 lines
2.5 KiB
Markdown
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<!--
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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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# multiply
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> Multiply two complex numbers.
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<section class="intro">
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</section>
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<!-- /.intro -->
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<section class="usage">
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## Usage
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```javascript
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var cmul = require( '@stdlib/math/base/ops/cmul' );
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```
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#### cmul( \[out,] re1, im1, re2, im2 )
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Multiplies two `complex` numbers where each `complex` number is comprised of a **real** component `re` and an **imaginary** component `im`.
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```javascript
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var v = cmul( 5.0, 3.0, -2.0, 1.0 );
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// returns [ -13.0, -1.0 ]
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```
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By default, the function returns real and imaginary components as a two-element `array`. To avoid unnecessary 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 = cmul( out, 5.0, 3.0, -2.0, 1.0 );
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// returns <Float64Array>[ -13.0, -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 Complex128 = require( '@stdlib/complex/float64' );
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var randu = require( '@stdlib/random/base/randu' );
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var round = require( '@stdlib/math/base/special/round' );
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var real = require( '@stdlib/complex/real' );
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var imag = require( '@stdlib/complex/imag' );
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var cmul = require( '@stdlib/math/base/ops/cmul' );
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var re;
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var im;
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var z1;
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var z2;
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var z3;
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var o;
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var i;
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for ( i = 0; i < 100; i++ ) {
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re = round( randu()*100.0 ) - 50.0;
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im = round( randu()*100.0 ) - 50.0;
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z1 = new Complex128( re, im );
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re = round( randu()*100.0 ) - 50.0;
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im = round( randu()*100.0 ) - 50.0;
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z2 = new Complex128( re, im );
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o = cmul( real(z1), imag(z1), real(z2), imag(z2) );
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z3 = new Complex128( o[ 0 ], o[ 1 ] );
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console.log( '(%s) * (%s) = %s', z1.toString(), z2.toString(), z3.toString() );
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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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</section>
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<!-- /.links -->
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