time-to-botec/js/node_modules/@stdlib/math/base/special/heaviside/README.md

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# Heaviside Function
> Evaluate the [Heaviside function][heaviside-function].
<section class="intro">
The [Heaviside function][heaviside-function] is defined as
<!-- <equation class="equation" label="eq:heaviside_function" align="center" raw="H(x) = \begin{cases} 1 & \textrm{if}\ x \gt 0 \\ 0 & \textrm{if}\ x \lt 0\end{cases}" alt="Heaviside function."> -->
<div class="equation" align="center" data-raw-text="H(x) = \begin{cases} 1 &amp; \textrm{if}\ x \gt 0 \\ 0 &amp; \textrm{if}\ x \lt 0\end{cases}" data-equation="eq:heaviside_function">
<img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@bb29798906e119fcb2af99e94b60407a270c9b32/lib/node_modules/@stdlib/math/base/special/heaviside/docs/img/equation_heaviside_function.svg" alt="Heaviside function.">
<br>
</div>
<!-- </equation> -->
and is discontinuous at `0`. Depending on the context, the [Heaviside function][heaviside-function] may be defined as a continuous function. To define the [Heaviside function][heaviside-function] such that the function has rotational symmetry,
<!-- <equation class="equation" label="eq:heaviside_function_half_maximum" align="center" raw="H(x) = \begin{cases} x & \textrm{if}\ x \gt 0 \\ \frac{1}{2} & \textrm{if}\ x = 0 \\ 0 & \textrm{if}\ x \lt 0\end{cases}" alt="Heaviside function half-maximum."> -->
<div class="equation" align="center" data-raw-text="H(x) = \begin{cases} x &amp; \textrm{if}\ x \gt 0 \\ \frac{1}{2} &amp; \textrm{if}\ x = 0 \\ 0 &amp; \textrm{if}\ x \lt 0\end{cases}" data-equation="eq:heaviside_function_half_maximum">
<img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@bb29798906e119fcb2af99e94b60407a270c9b32/lib/node_modules/@stdlib/math/base/special/heaviside/docs/img/equation_heaviside_function_half_maximum.svg" alt="Heaviside function half-maximum.">
<br>
</div>
<!-- </equation> -->
To define the [Heaviside function][heaviside-function] as a left-continuous function,
<!-- <equation class="equation" label="eq:heaviside_function_left_continuous" align="center" raw="H(x) = \begin{cases} x & \textrm{if}\ x \gt 0 \\ 0 & \textrm{if}\ x \leq 0\end{cases}" alt="Heaviside function left-continuous."> -->
<div class="equation" align="center" data-raw-text="H(x) = \begin{cases} x &amp; \textrm{if}\ x \gt 0 \\ 0 &amp; \textrm{if}\ x \leq 0\end{cases}" data-equation="eq:heaviside_function_left_continuous">
<img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@bb29798906e119fcb2af99e94b60407a270c9b32/lib/node_modules/@stdlib/math/base/special/heaviside/docs/img/equation_heaviside_function_left_continuous.svg" alt="Heaviside function left-continuous.">
<br>
</div>
<!-- </equation> -->
To define the [Heaviside function][heaviside-function] as a right-continuous function,
<!-- <equation class="equation" label="eq:heaviside_function_right_continuous" align="center" raw="H(x) = \begin{cases} x & \textrm{if}\ x \geq 0 \\ 0 & \textrm{if}\ x \lt 0\end{cases}" alt="Heaviside function right-continuous."> -->
<div class="equation" align="center" data-raw-text="H(x) = \begin{cases} x &amp; \textrm{if}\ x \geq 0 \\ 0 &amp; \textrm{if}\ x \lt 0\end{cases}" data-equation="eq:heaviside_function_right_continuous">
<img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@bb29798906e119fcb2af99e94b60407a270c9b32/lib/node_modules/@stdlib/math/base/special/heaviside/docs/img/equation_heaviside_function_right_continuous.svg" alt="Heaviside function right-continuous.">
<br>
</div>
<!-- </equation> -->
</section>
<!-- /.intro -->
<section class="usage">
## Usage
```javascript
var heaviside = require( '@stdlib/math/base/special/heaviside' );
```
#### heaviside( x\[, continuity] )
Evaluates the [Heaviside function][heaviside-function].
```javascript
var v = heaviside( 3.14 );
// returns 1.0
v = heaviside( -3.14 );
// returns 0.0
v = heaviside( NaN );
// returns NaN
```
The `continuity` parameter may be one of the following values:
- `'half-maximum'`: if `x == 0`, the function returns `0.5`.
- `'left-continuous'`: if `x == 0`, the function returns `0.0`.
- `'right-continuous'`: if `x == 0`, the function returns `1.0`.
By default, the function is discontinuous at `0`.
```javascript
var v = heaviside( 0.0 );
// returns NaN
```
To define the [Heaviside function][heaviside-function] as a continuous function, set the `continuity` parameter.
```javascript
var v = heaviside( 0.0, 'half-maximum' );
// returns 0.5
v = heaviside( 0.0, 'left-continuous' );
// returns 0.0
v = heaviside( 0.0, 'right-continuous' );
// returns 1.0
```
</section>
<!-- /.usage -->
<section class="examples">
## Examples
<!-- eslint no-undef: "error" -->
```javascript
var linspace = require( '@stdlib/array/linspace' );
var heaviside = require( '@stdlib/math/base/special/heaviside' );
var x = linspace( -10.0, 10.0, 101 );
var i;
for ( i = 0; i < x.length; i++ ) {
console.log( 'H(%d) = %d', x[ i ], heaviside( x[ i ] ) );
}
```
</section>
<!-- /.examples -->
<section class="links">
[heaviside-function]: https://en.wikipedia.org/wiki/Heaviside_step_function
</section>
<!-- /.links -->