import numpy as np
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from numpy import ma
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from matplotlib import cbook, docstring, rcParams
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from matplotlib.ticker import (
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NullFormatter, ScalarFormatter, LogFormatterSciNotation, LogitFormatter,
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NullLocator, LogLocator, AutoLocator, AutoMinorLocator,
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SymmetricalLogLocator, LogitLocator)
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from matplotlib.transforms import Transform, IdentityTransform
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class ScaleBase(object):
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"""
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The base class for all scales.
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Scales are separable transformations, working on a single dimension.
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Any subclasses will want to override:
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- :attr:`name`
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- :meth:`get_transform`
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- :meth:`set_default_locators_and_formatters`
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And optionally:
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- :meth:`limit_range_for_scale`
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"""
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def get_transform(self):
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"""
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Return the :class:`~matplotlib.transforms.Transform` object
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associated with this scale.
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"""
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raise NotImplementedError()
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def set_default_locators_and_formatters(self, axis):
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"""
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Set the :class:`~matplotlib.ticker.Locator` and
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:class:`~matplotlib.ticker.Formatter` objects on the given
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axis to match this scale.
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"""
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raise NotImplementedError()
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def limit_range_for_scale(self, vmin, vmax, minpos):
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"""
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Returns the range *vmin*, *vmax*, possibly limited to the
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domain supported by this scale.
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*minpos* should be the minimum positive value in the data.
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This is used by log scales to determine a minimum value.
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"""
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return vmin, vmax
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class LinearScale(ScaleBase):
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"""
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The default linear scale.
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"""
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name = 'linear'
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def __init__(self, axis, **kwargs):
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pass
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def set_default_locators_and_formatters(self, axis):
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"""
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Set the locators and formatters to reasonable defaults for
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linear scaling.
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"""
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axis.set_major_locator(AutoLocator())
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axis.set_major_formatter(ScalarFormatter())
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axis.set_minor_formatter(NullFormatter())
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# update the minor locator for x and y axis based on rcParams
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if rcParams['xtick.minor.visible']:
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axis.set_minor_locator(AutoMinorLocator())
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else:
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axis.set_minor_locator(NullLocator())
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def get_transform(self):
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"""
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The transform for linear scaling is just the
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:class:`~matplotlib.transforms.IdentityTransform`.
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"""
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return IdentityTransform()
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class LogTransformBase(Transform):
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input_dims = 1
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output_dims = 1
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is_separable = True
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has_inverse = True
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def __init__(self, nonpos='clip'):
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Transform.__init__(self)
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self._clip = {"clip": True, "mask": False}[nonpos]
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def transform_non_affine(self, a):
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# Ignore invalid values due to nans being passed to the transform
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with np.errstate(divide="ignore", invalid="ignore"):
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out = np.log(a)
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out /= np.log(self.base)
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if self._clip:
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# SVG spec says that conforming viewers must support values up
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# to 3.4e38 (C float); however experiments suggest that
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# Inkscape (which uses cairo for rendering) runs into cairo's
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# 24-bit limit (which is apparently shared by Agg).
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# Ghostscript (used for pdf rendering appears to overflow even
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# earlier, with the max value around 2 ** 15 for the tests to
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# pass. On the other hand, in practice, we want to clip beyond
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# np.log10(np.nextafter(0, 1)) ~ -323
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# so 1000 seems safe.
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out[a <= 0] = -1000
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return out
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def __str__(self):
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return "{}({!r})".format(
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type(self).__name__, "clip" if self._clip else "mask")
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class InvertedLogTransformBase(Transform):
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input_dims = 1
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output_dims = 1
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is_separable = True
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has_inverse = True
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def transform_non_affine(self, a):
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return ma.power(self.base, a)
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def __str__(self):
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return "{}()".format(type(self).__name__)
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class Log10Transform(LogTransformBase):
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base = 10.0
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def inverted(self):
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return InvertedLog10Transform()
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class InvertedLog10Transform(InvertedLogTransformBase):
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base = 10.0
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def inverted(self):
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return Log10Transform()
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class Log2Transform(LogTransformBase):
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base = 2.0
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def inverted(self):
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return InvertedLog2Transform()
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class InvertedLog2Transform(InvertedLogTransformBase):
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base = 2.0
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def inverted(self):
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return Log2Transform()
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class NaturalLogTransform(LogTransformBase):
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base = np.e
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def inverted(self):
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return InvertedNaturalLogTransform()
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class InvertedNaturalLogTransform(InvertedLogTransformBase):
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base = np.e
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def inverted(self):
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return NaturalLogTransform()
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class LogTransform(LogTransformBase):
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def __init__(self, base, nonpos='clip'):
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LogTransformBase.__init__(self, nonpos)
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self.base = base
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def inverted(self):
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return InvertedLogTransform(self.base)
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class InvertedLogTransform(InvertedLogTransformBase):
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def __init__(self, base):
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InvertedLogTransformBase.__init__(self)
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self.base = base
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def inverted(self):
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return LogTransform(self.base)
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class LogScale(ScaleBase):
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"""
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A standard logarithmic scale. Care is taken so non-positive
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values are not plotted.
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For computational efficiency (to push as much as possible to Numpy
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C code in the common cases), this scale provides different
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transforms depending on the base of the logarithm:
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- base 10 (:class:`Log10Transform`)
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- base 2 (:class:`Log2Transform`)
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- base e (:class:`NaturalLogTransform`)
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- arbitrary base (:class:`LogTransform`)
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"""
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name = 'log'
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# compatibility shim
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LogTransformBase = LogTransformBase
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Log10Transform = Log10Transform
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InvertedLog10Transform = InvertedLog10Transform
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Log2Transform = Log2Transform
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InvertedLog2Transform = InvertedLog2Transform
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NaturalLogTransform = NaturalLogTransform
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InvertedNaturalLogTransform = InvertedNaturalLogTransform
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LogTransform = LogTransform
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InvertedLogTransform = InvertedLogTransform
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def __init__(self, axis, **kwargs):
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"""
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*basex*/*basey*:
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The base of the logarithm
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*nonposx*/*nonposy*: {'mask', 'clip'}
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non-positive values in *x* or *y* can be masked as
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invalid, or clipped to a very small positive number
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*subsx*/*subsy*:
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Where to place the subticks between each major tick.
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Should be a sequence of integers. For example, in a log10
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scale: ``[2, 3, 4, 5, 6, 7, 8, 9]``
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will place 8 logarithmically spaced minor ticks between
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each major tick.
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"""
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if axis.axis_name == 'x':
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base = kwargs.pop('basex', 10.0)
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subs = kwargs.pop('subsx', None)
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nonpos = kwargs.pop('nonposx', 'clip')
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else:
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base = kwargs.pop('basey', 10.0)
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subs = kwargs.pop('subsy', None)
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nonpos = kwargs.pop('nonposy', 'clip')
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if len(kwargs):
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raise ValueError(("provided too many kwargs, can only pass "
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"{'basex', 'subsx', nonposx'} or "
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"{'basey', 'subsy', nonposy'}. You passed ") +
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"{!r}".format(kwargs))
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if nonpos not in ['mask', 'clip']:
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raise ValueError("nonposx, nonposy kwarg must be 'mask' or 'clip'")
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if base <= 0 or base == 1:
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raise ValueError('The log base cannot be <= 0 or == 1')
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if base == 10.0:
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self._transform = self.Log10Transform(nonpos)
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elif base == 2.0:
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self._transform = self.Log2Transform(nonpos)
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elif base == np.e:
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self._transform = self.NaturalLogTransform(nonpos)
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else:
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self._transform = self.LogTransform(base, nonpos)
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self.base = base
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self.subs = subs
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def set_default_locators_and_formatters(self, axis):
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"""
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Set the locators and formatters to specialized versions for
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log scaling.
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"""
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axis.set_major_locator(LogLocator(self.base))
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axis.set_major_formatter(LogFormatterSciNotation(self.base))
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axis.set_minor_locator(LogLocator(self.base, self.subs))
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axis.set_minor_formatter(
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LogFormatterSciNotation(self.base,
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labelOnlyBase=(self.subs is not None)))
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def get_transform(self):
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"""
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Return a :class:`~matplotlib.transforms.Transform` instance
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appropriate for the given logarithm base.
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"""
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return self._transform
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def limit_range_for_scale(self, vmin, vmax, minpos):
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"""
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Limit the domain to positive values.
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"""
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if not np.isfinite(minpos):
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minpos = 1e-300 # This value should rarely if ever
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# end up with a visible effect.
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return (minpos if vmin <= 0 else vmin,
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minpos if vmax <= 0 else vmax)
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class SymmetricalLogTransform(Transform):
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input_dims = 1
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output_dims = 1
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is_separable = True
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has_inverse = True
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def __init__(self, base, linthresh, linscale):
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Transform.__init__(self)
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self.base = base
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self.linthresh = linthresh
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self.linscale = linscale
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self._linscale_adj = (linscale / (1.0 - self.base ** -1))
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self._log_base = np.log(base)
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def transform_non_affine(self, a):
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sign = np.sign(a)
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masked = ma.masked_inside(a,
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-self.linthresh,
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self.linthresh,
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copy=False)
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log = sign * self.linthresh * (
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self._linscale_adj +
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ma.log(np.abs(masked) / self.linthresh) / self._log_base)
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if masked.mask.any():
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return ma.where(masked.mask, a * self._linscale_adj, log)
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else:
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return log
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def inverted(self):
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return InvertedSymmetricalLogTransform(self.base, self.linthresh,
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self.linscale)
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class InvertedSymmetricalLogTransform(Transform):
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input_dims = 1
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output_dims = 1
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is_separable = True
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has_inverse = True
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def __init__(self, base, linthresh, linscale):
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Transform.__init__(self)
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symlog = SymmetricalLogTransform(base, linthresh, linscale)
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self.base = base
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self.linthresh = linthresh
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self.invlinthresh = symlog.transform(linthresh)
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self.linscale = linscale
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self._linscale_adj = (linscale / (1.0 - self.base ** -1))
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def transform_non_affine(self, a):
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sign = np.sign(a)
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masked = ma.masked_inside(a, -self.invlinthresh,
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self.invlinthresh, copy=False)
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exp = sign * self.linthresh * (
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ma.power(self.base, (sign * (masked / self.linthresh))
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- self._linscale_adj))
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if masked.mask.any():
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return ma.where(masked.mask, a / self._linscale_adj, exp)
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else:
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return exp
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def inverted(self):
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return SymmetricalLogTransform(self.base,
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self.linthresh, self.linscale)
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class SymmetricalLogScale(ScaleBase):
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"""
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The symmetrical logarithmic scale is logarithmic in both the
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positive and negative directions from the origin.
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Since the values close to zero tend toward infinity, there is a
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need to have a range around zero that is linear. The parameter
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*linthresh* allows the user to specify the size of this range
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(-*linthresh*, *linthresh*).
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"""
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name = 'symlog'
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# compatibility shim
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SymmetricalLogTransform = SymmetricalLogTransform
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InvertedSymmetricalLogTransform = InvertedSymmetricalLogTransform
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def __init__(self, axis, **kwargs):
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"""
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*basex*/*basey*:
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The base of the logarithm
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*linthreshx*/*linthreshy*:
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A single float which defines the range (-*x*, *x*), within
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which the plot is linear. This avoids having the plot go to
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infinity around zero.
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*subsx*/*subsy*:
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Where to place the subticks between each major tick.
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Should be a sequence of integers. For example, in a log10
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scale: ``[2, 3, 4, 5, 6, 7, 8, 9]``
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will place 8 logarithmically spaced minor ticks between
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each major tick.
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*linscalex*/*linscaley*:
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This allows the linear range (-*linthresh* to *linthresh*)
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to be stretched relative to the logarithmic range. Its
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value is the number of decades to use for each half of the
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linear range. For example, when *linscale* == 1.0 (the
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default), the space used for the positive and negative
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halves of the linear range will be equal to one decade in
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the logarithmic range.
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"""
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if axis.axis_name == 'x':
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base = kwargs.pop('basex', 10.0)
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linthresh = kwargs.pop('linthreshx', 2.0)
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subs = kwargs.pop('subsx', None)
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linscale = kwargs.pop('linscalex', 1.0)
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else:
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base = kwargs.pop('basey', 10.0)
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linthresh = kwargs.pop('linthreshy', 2.0)
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subs = kwargs.pop('subsy', None)
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linscale = kwargs.pop('linscaley', 1.0)
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if base <= 1.0:
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raise ValueError("'basex/basey' must be larger than 1")
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if linthresh <= 0.0:
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raise ValueError("'linthreshx/linthreshy' must be positive")
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if linscale <= 0.0:
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raise ValueError("'linscalex/linthreshy' must be positive")
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self._transform = self.SymmetricalLogTransform(base,
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linthresh,
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linscale)
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self.base = base
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self.linthresh = linthresh
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self.linscale = linscale
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self.subs = subs
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def set_default_locators_and_formatters(self, axis):
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"""
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Set the locators and formatters to specialized versions for
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symmetrical log scaling.
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"""
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axis.set_major_locator(SymmetricalLogLocator(self.get_transform()))
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axis.set_major_formatter(LogFormatterSciNotation(self.base))
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axis.set_minor_locator(SymmetricalLogLocator(self.get_transform(),
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self.subs))
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axis.set_minor_formatter(NullFormatter())
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def get_transform(self):
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"""
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Return a :class:`SymmetricalLogTransform` instance.
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"""
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return self._transform
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class LogitTransform(Transform):
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input_dims = 1
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output_dims = 1
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is_separable = True
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has_inverse = True
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def __init__(self, nonpos='mask'):
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Transform.__init__(self)
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self._nonpos = nonpos
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self._clip = {"clip": True, "mask": False}[nonpos]
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def transform_non_affine(self, a):
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"""logit transform (base 10), masked or clipped"""
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with np.errstate(divide="ignore", invalid="ignore"):
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out = np.log10(a / (1 - a))
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if self._clip: # See LogTransform for choice of clip value.
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out[a <= 0] = -1000
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out[1 <= a] = 1000
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return out
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def inverted(self):
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return LogisticTransform(self._nonpos)
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def __str__(self):
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return "{}({!r})".format(type(self).__name__,
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"clip" if self._clip else "mask")
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|
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class LogisticTransform(Transform):
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input_dims = 1
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output_dims = 1
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is_separable = True
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has_inverse = True
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def __init__(self, nonpos='mask'):
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Transform.__init__(self)
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self._nonpos = nonpos
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def transform_non_affine(self, a):
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"""logistic transform (base 10)"""
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return 1.0 / (1 + 10**(-a))
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def inverted(self):
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return LogitTransform(self._nonpos)
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def __str__(self):
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return "{}({!r})".format(type(self).__name__, self._nonpos)
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class LogitScale(ScaleBase):
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"""
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Logit scale for data between zero and one, both excluded.
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This scale is similar to a log scale close to zero and to one, and almost
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linear around 0.5. It maps the interval ]0, 1[ onto ]-infty, +infty[.
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"""
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name = 'logit'
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def __init__(self, axis, nonpos='mask'):
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"""
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*nonpos*: {'mask', 'clip'}
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values beyond ]0, 1[ can be masked as invalid, or clipped to a number
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very close to 0 or 1
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"""
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if nonpos not in ['mask', 'clip']:
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raise ValueError("nonposx, nonposy kwarg must be 'mask' or 'clip'")
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self._transform = LogitTransform(nonpos)
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def get_transform(self):
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"""
|
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Return a :class:`LogitTransform` instance.
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"""
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return self._transform
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|
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def set_default_locators_and_formatters(self, axis):
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# ..., 0.01, 0.1, 0.5, 0.9, 0.99, ...
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axis.set_major_locator(LogitLocator())
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axis.set_major_formatter(LogitFormatter())
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axis.set_minor_locator(LogitLocator(minor=True))
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axis.set_minor_formatter(LogitFormatter())
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def limit_range_for_scale(self, vmin, vmax, minpos):
|
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"""
|
|
Limit the domain to values between 0 and 1 (excluded).
|
|
"""
|
|
if not np.isfinite(minpos):
|
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minpos = 1e-7 # This value should rarely if ever
|
|
# end up with a visible effect.
|
|
return (minpos if vmin <= 0 else vmin,
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1 - minpos if vmax >= 1 else vmax)
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|
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_scale_mapping = {
|
|
'linear': LinearScale,
|
|
'log': LogScale,
|
|
'symlog': SymmetricalLogScale,
|
|
'logit': LogitScale,
|
|
}
|
|
|
|
|
|
def get_scale_names():
|
|
return sorted(_scale_mapping)
|
|
|
|
|
|
def scale_factory(scale, axis, **kwargs):
|
|
"""
|
|
Return a scale class by name.
|
|
|
|
ACCEPTS: [ %(names)s ]
|
|
"""
|
|
scale = scale.lower()
|
|
if scale is None:
|
|
scale = 'linear'
|
|
|
|
if scale not in _scale_mapping:
|
|
raise ValueError("Unknown scale type '%s'" % scale)
|
|
|
|
return _scale_mapping[scale](axis, **kwargs)
|
|
scale_factory.__doc__ = cbook.dedent(scale_factory.__doc__) % \
|
|
{'names': " | ".join(get_scale_names())}
|
|
|
|
|
|
def register_scale(scale_class):
|
|
"""
|
|
Register a new kind of scale.
|
|
|
|
*scale_class* must be a subclass of :class:`ScaleBase`.
|
|
"""
|
|
_scale_mapping[scale_class.name] = scale_class
|
|
|
|
|
|
def get_scale_docs():
|
|
"""
|
|
Helper function for generating docstrings related to scales.
|
|
"""
|
|
docs = []
|
|
for name in get_scale_names():
|
|
scale_class = _scale_mapping[name]
|
|
docs.append(" '%s'" % name)
|
|
docs.append("")
|
|
class_docs = cbook.dedent(scale_class.__init__.__doc__)
|
|
class_docs = "".join([" %s\n" %
|
|
x for x in class_docs.split("\n")])
|
|
docs.append(class_docs)
|
|
docs.append("")
|
|
return "\n".join(docs)
|
|
|
|
|
|
docstring.interpd.update(
|
|
scale=' | '.join([repr(x) for x in get_scale_names()]),
|
|
scale_docs=get_scale_docs().rstrip(),
|
|
)
|