sphere.py 文件源码

 复制代码def get_min_level(self, value):
        """Minimum cell level for given value.

        Return the minimum level such that the metric is at most the given
        value, or ``s2sphere.CellId.MAX_LEVEL`` if there is no such level.
        For example, ``s2sphere.MAX_DIAG.get_min_level(0.1)`` returns the
        minimum level such that all cell diagonal lengths are 0.1 or smaller.
        The return value is always a valid level.

        :param value:
            Depending on whether this is used in one or two dimensions, this is
            an angle in radians or a solid angle in steradians.
        """
        if value <= 0:
            return CellId.MAX_LEVEL

        m, x = math.frexp(value / self.deriv())
        level = max(0, min(CellId.MAX_LEVEL, -((x - 1) >> (self.__dim - 1))))
        assert level == CellId.MAX_LEVEL or self.get_value(level) <= value
        assert level == 0 or self.get_value(level - 1) > value
        return level