##
## symlog tick helper
from matplotlib.ticker import Locator


class MinorSymLogLocator(Locator):
    """
    Dynamically find minor tick positions based on the positions of
    major ticks for a symlog scaling.
    """

    def __init__(self, linthresh):
        """
        Ticks will be placed between the major ticks.
        The placement is linear for x between -linthresh and linthresh,
        otherwise its logarithmically
        """
        self.linthresh = linthresh

    def __call__(self):
        import numpy as np

        "Return the locations of the ticks"
        majorlocs = self.axis.get_majorticklocs()
        majorlocs = np.append(majorlocs, majorlocs[-1] * 10.0)
        majorlocs = np.append(majorlocs[0] * 0.1, majorlocs)

        # iterate through minor locs
        minorlocs = []

        # handle the lowest part
        for i in xrange(1, len(majorlocs)):
            majorstep = majorlocs[i] - majorlocs[i - 1]
            if abs(majorlocs[i - 1] + majorstep / 2) < self.linthresh:
                ndivs = 10
            else:
                ndivs = 9
            minorstep = majorstep / ndivs
            locs = np.arange(majorlocs[i - 1], majorlocs[i], minorstep)[1:]
            minorlocs.extend(locs)

        return self.raise_if_exceeds(np.array(minorlocs))

        def tick_values(self, vmin, vmax):
            raise NotImplementedError(
                "Cannot get tick locations for a " "%s type." % type(self)
            )