gamajo/quadratic

Handle solving of quadratic equations.

Gamajo Quadratic Equation Solver

PHP classes for working with, and solving, quadratic equations., _(*1)

What Is A Quadratic Equation?

A quadratic equation is a univariate polynomial with degree of 2, that is then set to equal zero so that the indeterminate can be determined:, _(*2)

ax² + bx + c = 0, _(*3)

Equations can often be solved with factoring or completing the square, but there is also a Quadratic Formula:, _(*4)

, _(*5)

The QuadraticEquation interface constructor accepts values for a, b and c and the Solver can return one or both roots, including imaginary roots., _(*6)

Installation

composer require gamajo/quadratic --save

Requires PHP 7., _(*7)

Usage

Basic Usage

Create an equation object, pass that to the solver, solve, and retrieve the roots:, _(*8)

use Gamajo\Quadratic;

// Represents x^2 + 5x + 6 = 0.
$equation = new BasicQuadraticEquation(1, 5, 6);

$solver = new Solver($equation);
$solver->solve();

echo $solver->get(); // '2 and 3'
echo $solver->get('root1'); // '2'
echo $solver->get('root2'); // '3'

The Solver has no problem with complex roots:, _(*9)

use Gamajo\Quadratic;

// Represents 3x^2 + 4x + 5 = 0.
$equation = new BasicQuadraticEquation(3, 4, 5);

$solver = new Solver($equation);
$solver->solve();

echo $solver->get(); // '-0.667 + 1.106i and -0.667 - 1.106i'

BasicQuadraticEquation Methods

The BasicQuadraticEquation class implements the QuadraticEquation interface, which in turn extends the Equation interface. As such, it supports the following methods:, _(*10)

use Gamajo\Quadratic;

// Represents x^2 + 5x + 6 = 0.
$equation = new BasicQuadraticEquation(1, 5, 6);

echo $equation->getA(); // 1
echo $equation->getB(); // 5
echo $equation->getC(); // 6
print_r( $equation->getArgsAsArray() ); // [1, 5, 6]

There is also a hasValidArguments() method, but as this library uses scalar type declarations, the manual check to see if they are all integers is somewhat redundant., _(*11)

Solver Methods

The Solver class can optionally set the maximum decimal place precision of the roots:, _(*12)

use Gamajo\Quadratic;

// Represents 8x^2 + 5x - 2 = 0.
$equation = new BasicQuadraticEquation(8, 5, -2);

$solver = new Solver($equation);
$solve->setPrecision(4); // Default precision is 3

echo $solve->getPrecision(); // 4

$solver->solve();

echo $solver->get(); // '-0.9021 and 0.2771' instead of '-0.902 and 0.277'

Change Log

See the change log., _(*13)

License

MIT., _(*14)

Contributions

Contributions are welcome - fork, fix and send pull requests against the develop branch please., _(*15)

Credits

Built by Gary Jones.
Original procedural code version, copyright 2004 Gary Jones.
This version copyright 2016 Gamajo Tech, _(*16)