/**
* Return the maximum level such that the metric is at least the given
* value, or zero if there is no such level. For example,
* S2.kMinWidth.GetMaxLevel(0.1) returns the maximum level such that all
* cells have a minimum width of 0.1 or larger. The return value is always a
* valid level.
*/
public function getMaxLevel($value)
{
if ($value <= 0) {
return S2CellId::MAX_LEVEL;
}
// This code is equivalent to computing a floating-point "level"
// value and rounding down.
$exponent = S2::exp((1 << $this->dim) * $this->deriv / $value);
$level = max(0, min(S2CellId::MAX_LEVEL, $exponent - 1 >> $this->dim - 1));
// assert (level == 0 || getValue(level) >= value);
// assert (level == S2CellId.MAX_LEVEL || getValue(level + 1) < value);
return $level;
}
