| private static validate ( callable $function, number $a, number $b, number $tol ) | ||
| $function | callable | f(x) callback function |
| $a | number | The start of the interval which contains a root |
| $b | number | The end of the interval which contains a root |
| $tol | number | Tolerance; How close to the actual solution we would like. |
private static function validate(callable $function, $a, $b, $tol)
{
Validation::tolerance($tol);
Validation::interval($a, $b);
$f⟮a⟯ = $function($a);
$f⟮b⟯ = $function($b);
if (Special::sgn($f⟮a⟯) === Special::sgn($f⟮b⟯)) {
throw new Exception\BadDataException('Input function has the same sign at the start and end of the interval. Choose start and end points such that the function evaluated at those points has a different sign (one positive, one negative).');
}
}