public function testGcd()
{
$this->assertEquals(4, Math::gcd(8, 12));
$this->assertEquals(4, Math::gcd(12, 8));
$this->assertEquals(1, Math::gcd(12, 7));
// Edge cases
$this->assertEquals(5, Math::gcd(0, 5));
$this->assertEquals(0, Math::gcd(0, 0));
$this->assertEquals(-2, Math::gcd(2, -2));
$this->assertEquals(2, Math::gcd(-2, -2));
}
/**
* Normalize, i.e. make sure the denominator is positive and that
* the numerator and denominator have no common factors
*/
private function normalize()
{
$gcd = Math::gcd($this->p, $this->q);
if ($gcd == 0) {
throw new DivisionByZeroException();
}
$this->p = $this->p / $gcd;
$this->q = $this->q / $gcd;
if ($this->q < 0) {
$this->p = -$this->p;
$this->q = -$this->q;
}
}
