219 lines
4.1 KiB
Markdown
219 lines
4.1 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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# pdiff
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> Return the positive difference between `x` and `y`.
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<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
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<section class="intro">
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</section>
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<!-- /.intro -->
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<!-- Package usage documentation. -->
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<section class="usage">
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## Usage
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```javascript
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var pdiff = require( '@stdlib/math/base/special/pdiff' );
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```
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#### pdiff( x, y )
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Returns the positive difference between `x` and `y` if `x < y`; otherwise, returns `0`.
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```javascript
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var v = pdiff( 4.2, 3.14 );
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// returns 1.06
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v = pdiff( 3.14, 4.2 );
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// returns +0.0
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v = pdiff( -0.0, +0.0 );
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// returns +0.0
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```
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If any argument is `NaN`, the function returns `NaN`.
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```javascript
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var v = pdiff( 4.2, NaN );
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// returns NaN
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v = pdiff( NaN, 3.14 );
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// returns NaN
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v = pdiff( NaN, 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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<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="notes">
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## Notes
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- This function is the equivalent of [`fdim`][fdim] in the C/C++ standard library.
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</section>
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<!-- /.notes -->
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<!-- Package usage examples. -->
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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 minstd = require( '@stdlib/random/base/minstd-shuffle' );
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var pdiff = require( '@stdlib/math/base/special/pdiff' );
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var x;
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var y;
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var v;
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var i;
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for ( i = 0; i < 100; i++ ) {
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x = minstd();
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y = minstd();
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v = pdiff( x, y );
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console.log( 'pdiff(%d,%d) = %d', x, y, v );
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}
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```
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</section>
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<!-- /.examples -->
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<!-- C interface documentation. -->
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* * *
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<section class="c">
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## C APIs
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<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
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<section class="intro">
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</section>
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<!-- /.intro -->
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<!-- C usage documentation. -->
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<section class="usage">
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### Usage
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```c
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#include "stdlib/math/base/special/pdiff.h
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```
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#### stdlib_base_pdiff( x, y )
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Returns the positive difference between `x` and `y`.
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```c
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double v = stdlib_base_pdiff( 4.0, 3.0 );
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// returns 1.0
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```
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The function accepts the following arguments:
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- **x**: `[in] double` input value.
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- **y**: `[in] double` input value.
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```c
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double stdlib_base_pdiff( const double x, const double y );
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```
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</section>
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<!-- /.usage -->
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<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="notes">
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</section>
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<!-- /.notes -->
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<!-- C API usage examples. -->
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<section class="examples">
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### Examples
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```c
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#include "stdlib/math/base/special/pdiff.h"
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#include <stdio.h>
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int main() {
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double x[] = { 3.0, 4.0, 6.0, 5.0 };
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double y;
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int i;
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for ( i = 0; i < 4; i += 2 ) {
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y = stdlib_base_pdiff( x[ i ], x[ i+1 ] );
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printf( "pdiff(%lf, %lf) = %lf\n", x[ i ], x[ i+1 ], y );
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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>
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<!-- /.c -->
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<!-- 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. -->
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<section class="references">
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</section>
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<!-- /.references -->
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<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="links">
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[fdim]: http://en.cppreference.com/w/cpp/numeric/math/fdim
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</section>
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<!-- /.links -->
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