/**
* Returns the angle between the two vectors.
*
* @api
* @param self $b The vector to compute the angle between.
* @return float The angle between the two vectors in radians.
* @throws Exception if either of the vectors are zero-length.
* @throws Exception if the vectors are not in the same vector space.
* @see self::_checkVectorSpace() For exception information.
*/
public function angleBetween(self $b)
{
$denominator = $this->length() * $b->length();
if ($denominator == 0) {
throw new Exception('Cannot divide by zero');
}
return acos($this->dotProduct($b) / $denominator);
}
/**
* Verify that the length of the vector is correct.
*
* @test
* @uses \Nubs\Vectorix\Vector::__construct
* @uses \Nubs\Vectorix\Vector::components
* @covers ::length
*/
public function lengthIsCorrect()
{
$vector = new Vector([3, 4]);
$this->assertEquals(5.0, $vector->length(), '', 1.0E-10);
}
