89 lines
1.7 KiB
Markdown
89 lines
1.7 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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# log1pexp
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> Evaluates the [natural logarithm][@stdlib/math/base/special/ln] of `1+exp(x)`.
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<section class="usage">
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## Usage
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```javascript
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var log1pexp = require( '@stdlib/math/base/special/log1pexp' );
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```
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#### log1pexp( x )
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Evaluates the [natural logarithm][@stdlib/math/base/special/ln] of `1+exp(x)`.
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```javascript
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var y = log1pexp( -10.0 );
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// returns ~0.000045
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y = log1pexp( 0.0 );
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// returns ~0.693147
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y = log1pexp( 5.0 );
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// returns ~5.006715
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y = log1pexp( 34.0 );
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// returns 34.0
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y = log1pexp( NaN );
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// returns NaN
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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 incrspace = require( '@stdlib/array/incrspace' );
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var log1pexp = require( '@stdlib/math/base/special/log1pexp' );
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var x = incrspace( -10.0, 10.0, 0.01 );
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var v;
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var i;
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for ( i = 0; i < x.length; i++ ) {
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v = log1pexp( x[ i ] );
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console.log( 'x: %d, f(x): %d', x[ i ], v );
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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/ln]: https://www.npmjs.com/package/@stdlib/math/tree/main/base/special/ln
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</section>
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<!-- /.links -->
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