README

Piecewise math functions.

use Jstewmc\Fx\{Constant, Linear};
use Jstewmc\Interval\Interval;
use Jstewmc\PiecewiseFx;

// define our sub-functions...
//     y = 1     | 1 <= x <= 3
//     y = x - 2 | 3 < x <= 6
//     y = 4     | 6 < x <= 9
//
$subFxs = [
    new SubFx(
        new Interval('[1, 3]'),
        new Constant(1)
    ),
    new SubFx(
        new Interval('(3, 6]'),
        new Linear(1, -2)
    ),
    new SubFx(
        new Interval('(6, 9]'),
        new Constant(4)
    )
];

// define our piecewise fx
$fx = new PiecewiseFx($subFxs);

$fx(0);   // returns null
$fx(1);   // returns 1
$fx(2);   // returns 1
$fx(3);   // returns 1
$fx(4);   // returns 2
$fx(5);   // returns 3 
$fx(6);   // returns 4
$fx(7);   // returns 4
$fx(8);   // returns 4
$fx(9);   // returns 4
$fx(10);  // returns null

A piecewise function is a function composed of multiple sub-functions, each of which applies to an interval of the function's domain.

As you can see in the example above, a piecewise function requires an array of sub-functions. Each sub-function, in turn, requires an interval and function. To learn more about intervals and functions, see jstewmc/interval and jstewmc/fx for details, respectively.

License

MIT

Author

Jack Clayton

Version

1.0.0, August 13, 2016

• Major release
• Update composer.json

0.1.1, August 13, 2016

• Update composer.json

0.1.0, August 6, 2016

• Initial release