Version 3.1.1
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Source code for matplotlib.ticker

"""
Tick locating and formatting
============================

This module contains classes to support completely configurable tick
locating and formatting. Although the locators know nothing about major
or minor ticks, they are used by the Axis class to support major and
minor tick locating and formatting. Generic tick locators and
formatters are provided, as well as domain specific custom ones.

Default Formatter
-----------------

The default formatter identifies when the x-data being plotted is a
small range on top of a large offset. To reduce the chances that the
ticklabels overlap, the ticks are labeled as deltas from a fixed offset.
For example::

   ax.plot(np.arange(2000, 2010), range(10))

will have tick of 0-9 with an offset of +2e3. If this is not desired
turn off the use of the offset on the default formatter::

   ax.get_xaxis().get_major_formatter().set_useOffset(False)

set the rcParam ``axes.formatter.useoffset=False`` to turn it off
globally, or set a different formatter.

Tick locating
-------------

The Locator class is the base class for all tick locators. The locators
handle autoscaling of the view limits based on the data limits, and the
choosing of tick locations. A useful semi-automatic tick locator is
`MultipleLocator`. It is initialized with a base, e.g., 10, and it picks
axis limits and ticks that are multiples of that base.

The Locator subclasses defined here are

:class:`AutoLocator`
    `MaxNLocator` with simple defaults.  This is the default tick locator for
    most plotting.

:class:`MaxNLocator`
    Finds up to a max number of intervals with ticks at nice locations.

:class:`LinearLocator`
    Space ticks evenly from min to max.

:class:`LogLocator`
    Space ticks logarithmically from min to max.

:class:`MultipleLocator`
    Ticks and range are a multiple of base; either integer or float.

:class:`FixedLocator`
    Tick locations are fixed.

:class:`IndexLocator`
    Locator for index plots (e.g., where ``x = range(len(y))``).

:class:`NullLocator`
    No ticks.

:class:`SymmetricalLogLocator`
    Locator for use with with the symlog norm; works like `LogLocator` for the
    part outside of the threshold and adds 0 if inside the limits.

:class:`LogitLocator`
    Locator for logit scaling.

:class:`OldAutoLocator`
    Choose a `MultipleLocator` and dynamically reassign it for intelligent
    ticking during navigation.

:class:`AutoMinorLocator`
    Locator for minor ticks when the axis is linear and the
    major ticks are uniformly spaced.  Subdivides the major
    tick interval into a specified number of minor intervals,
    defaulting to 4 or 5 depending on the major interval.


There are a number of locators specialized for date locations - see
the `dates` module.

You can define your own locator by deriving from Locator. You must
override the ``__call__`` method, which returns a sequence of locations,
and you will probably want to override the autoscale method to set the
view limits from the data limits.

If you want to override the default locator, use one of the above or a custom
locator and pass it to the x or y axis instance. The relevant methods are::

  ax.xaxis.set_major_locator(xmajor_locator)
  ax.xaxis.set_minor_locator(xminor_locator)
  ax.yaxis.set_major_locator(ymajor_locator)
  ax.yaxis.set_minor_locator(yminor_locator)

The default minor locator is `NullLocator`, i.e., no minor ticks on by default.

Tick formatting
---------------

Tick formatting is controlled by classes derived from Formatter. The formatter
operates on a single tick value and returns a string to the axis.

:class:`NullFormatter`
    No labels on the ticks.

:class:`IndexFormatter`
    Set the strings from a list of labels.

:class:`FixedFormatter`
    Set the strings manually for the labels.

:class:`FuncFormatter`
    User defined function sets the labels.

:class:`StrMethodFormatter`
    Use string `format` method.

:class:`FormatStrFormatter`
    Use an old-style sprintf format string.

:class:`ScalarFormatter`
    Default formatter for scalars: autopick the format string.

:class:`LogFormatter`
    Formatter for log axes.

:class:`LogFormatterExponent`
    Format values for log axis using ``exponent = log_base(value)``.

:class:`LogFormatterMathtext`
    Format values for log axis using ``exponent = log_base(value)``
    using Math text.

:class:`LogFormatterSciNotation`
    Format values for log axis using scientific notation.

:class:`LogitFormatter`
    Probability formatter.

:class:`EngFormatter`
    Format labels in engineering notation

:class:`PercentFormatter`
    Format labels as a percentage

You can derive your own formatter from the Formatter base class by
simply overriding the ``__call__`` method. The formatter class has
access to the axis view and data limits.

To control the major and minor tick label formats, use one of the
following methods::

  ax.xaxis.set_major_formatter(xmajor_formatter)
  ax.xaxis.set_minor_formatter(xminor_formatter)
  ax.yaxis.set_major_formatter(ymajor_formatter)
  ax.yaxis.set_minor_formatter(yminor_formatter)

See :doc:`/gallery/ticks_and_spines/major_minor_demo` for an
example of setting major and minor ticks. See the :mod:`matplotlib.dates`
module for more information and examples of using date locators and formatters.
"""

import itertools
import logging
import locale
import math
import numpy as np
from matplotlib import rcParams
from matplotlib import cbook
from matplotlib import transforms as mtransforms

_log = logging.getLogger(__name__)

__all__ = ('TickHelper', 'Formatter', 'FixedFormatter',
           'NullFormatter', 'FuncFormatter', 'FormatStrFormatter',
           'StrMethodFormatter', 'ScalarFormatter', 'LogFormatter',
           'LogFormatterExponent', 'LogFormatterMathtext',
           'IndexFormatter', 'LogFormatterSciNotation',
           'LogitFormatter', 'EngFormatter', 'PercentFormatter',
           'Locator', 'IndexLocator', 'FixedLocator', 'NullLocator',
           'LinearLocator', 'LogLocator', 'AutoLocator',
           'MultipleLocator', 'MaxNLocator', 'AutoMinorLocator',
           'SymmetricalLogLocator', 'LogitLocator')


def _mathdefault(s):
    return '\\mathdefault{%s}' % s


class _DummyAxis(object):
    def __init__(self, minpos=0):
        self.dataLim = mtransforms.Bbox.unit()
        self.viewLim = mtransforms.Bbox.unit()
        self._minpos = minpos

    def get_view_interval(self):
        return self.viewLim.intervalx

    def set_view_interval(self, vmin, vmax):
        self.viewLim.intervalx = vmin, vmax

    def get_minpos(self):
        return self._minpos

    def get_data_interval(self):
        return self.dataLim.intervalx

    def set_data_interval(self, vmin, vmax):
        self.dataLim.intervalx = vmin, vmax

    def get_tick_space(self):
        # Just use the long-standing default of nbins==9
        return 9


[docs]class TickHelper(object): axis = None
[docs] def set_axis(self, axis): self.axis = axis
[docs] def create_dummy_axis(self, **kwargs): if self.axis is None: self.axis = _DummyAxis(**kwargs)
[docs] def set_view_interval(self, vmin, vmax): self.axis.set_view_interval(vmin, vmax)
[docs] def set_data_interval(self, vmin, vmax): self.axis.set_data_interval(vmin, vmax)
[docs] def set_bounds(self, vmin, vmax): self.set_view_interval(vmin, vmax) self.set_data_interval(vmin, vmax)
[docs]class Formatter(TickHelper): """ Create a string based on a tick value and location. """ # some classes want to see all the locs to help format # individual ones locs = [] def __call__(self, x, pos=None): """ Return the format for tick value *x* at position pos. ``pos=None`` indicates an unspecified location. """ raise NotImplementedError('Derived must override')
[docs] def format_ticks(self, values): """Return the tick labels for all the ticks at once.""" self.set_locs(values) return [self(value, i) for i, value in enumerate(values)]
[docs] def format_data(self, value): """ Returns the full string representation of the value with the position unspecified. """ return self.__call__(value)
[docs] def format_data_short(self, value): """ Return a short string version of the tick value. Defaults to the position-independent long value. """ return self.format_data(value)
[docs] def get_offset(self): return ''
[docs] def set_locs(self, locs): self.locs = locs
[docs] def fix_minus(self, s): """ Some classes may want to replace a hyphen for minus with the proper unicode symbol (U+2212) for typographical correctness. The default is to not replace it. Note, if you use this method, e.g., in :meth:`format_data` or call, you probably don't want to use it for :meth:`format_data_short` since the toolbar uses this for interactive coord reporting and I doubt we can expect GUIs across platforms will handle the unicode correctly. So for now the classes that override :meth:`fix_minus` should have an explicit :meth:`format_data_short` method """ return s
def _set_locator(self, locator): """Subclasses may want to override this to set a locator.""" pass
[docs]class IndexFormatter(Formatter): """ Format the position x to the nearest i-th label where ``i = int(x + 0.5)``. Positions where ``i < 0`` or ``i > len(list)`` have no tick labels. Parameters ---------- labels : list List of labels. """ def __init__(self, labels): self.labels = labels self.n = len(labels) def __call__(self, x, pos=None): """ Return the format for tick value `x` at position pos. The position is ignored and the value is rounded to the nearest integer, which is used to look up the label. """ i = int(x + 0.5) if i < 0 or i >= self.n: return '' else: return self.labels[i]
[docs]class NullFormatter(Formatter): """ Always return the empty string. """ def __call__(self, x, pos=None): """ Returns an empty string for all inputs. """ return ''
[docs]class FixedFormatter(Formatter): """ Return fixed strings for tick labels based only on position, not value. """ def __init__(self, seq): """ Set the sequence of strings that will be used for labels. """ self.seq = seq self.offset_string = '' def __call__(self, x, pos=None): """ Returns the label that matches the position regardless of the value. For positions ``pos < len(seq)``, return `seq[i]` regardless of `x`. Otherwise return empty string. `seq` is the sequence of strings that this object was initialized with. """ if pos is None or pos >= len(self.seq): return '' else: return self.seq[pos]
[docs] def get_offset(self): return self.offset_string
[docs] def set_offset_string(self, ofs): self.offset_string = ofs
[docs]class FuncFormatter(Formatter): """ Use a user-defined function for formatting. The function should take in two inputs (a tick value ``x`` and a position ``pos``), and return a string containing the corresponding tick label. """ def __init__(self, func): self.func = func def __call__(self, x, pos=None): """ Return the value of the user defined function. `x` and `pos` are passed through as-is. """ return self.func(x, pos)
[docs]class FormatStrFormatter(Formatter): """ Use an old-style ('%' operator) format string to format the tick. The format string should have a single variable format (%) in it. It will be applied to the value (not the position) of the tick. """ def __init__(self, fmt): self.fmt = fmt def __call__(self, x, pos=None): """ Return the formatted label string. Only the value `x` is formatted. The position is ignored. """ return self.fmt % x
[docs]class StrMethodFormatter(Formatter): """ Use a new-style format string (as used by `str.format()`) to format the tick. The field used for the value must be labeled `x` and the field used for the position must be labeled `pos`. """ def __init__(self, fmt): self.fmt = fmt def __call__(self, x, pos=None): """ Return the formatted label string. `x` and `pos` are passed to `str.format` as keyword arguments with those exact names. """ return self.fmt.format(x=x, pos=pos)
class OldScalarFormatter(Formatter): """ Tick location is a plain old number. """ def __call__(self, x, pos=None): """ Return the format for tick val `x` based on the width of the axis. The position `pos` is ignored. """ xmin, xmax = self.axis.get_view_interval() # If the number is not too big and it's an int, format it as an int. if abs(x) < 1e4 and x == int(x): return '%d' % x d = abs(xmax - xmin) fmt = ('%1.3e' if d < 1e-2 else '%1.3f' if d <= 1 else '%1.2f' if d <= 10 else '%1.1f' if d <= 1e5 else '%1.1e') s = fmt % x tup = s.split('e') if len(tup) == 2: mantissa = tup[0].rstrip('0').rstrip('.') sign = tup[1][0].replace('+', '') exponent = tup[1][1:].lstrip('0') s = '%se%s%s' % (mantissa, sign, exponent) else: s = s.rstrip('0').rstrip('.') return s @cbook.deprecated("3.1") def pprint_val(self, x, d): """ Formats the value `x` based on the size of the axis range `d`. """ # If the number is not too big and it's an int, format it as an int. if abs(x) < 1e4 and x == int(x): return '%d' % x if d < 1e-2: fmt = '%1.3e' elif d < 1e-1: fmt = '%1.3f' elif d > 1e5: fmt = '%1.1e' elif d > 10: fmt = '%1.1f' elif d > 1: fmt = '%1.2f' else: fmt = '%1.3f' s = fmt % x tup = s.split('e') if len(tup) == 2: mantissa = tup[0].rstrip('0').rstrip('.') sign = tup[1][0].replace('+', '') exponent = tup[1][1:].lstrip('0') s = '%se%s%s' % (mantissa, sign, exponent) else: s = s.rstrip('0').rstrip('.') return s
[docs]class ScalarFormatter(Formatter): """ Format tick values as a number. Tick value is interpreted as a plain old number. If ``useOffset==True`` and the data range is much smaller than the data average, then an offset will be determined such that the tick labels are meaningful. Scientific notation is used for ``data < 10^-n`` or ``data >= 10^m``, where ``n`` and ``m`` are the power limits set using ``set_powerlimits((n,m))``. The defaults for these are controlled by the ``axes.formatter.limits`` rc parameter. """ def __init__(self, useOffset=None, useMathText=None, useLocale=None): # useOffset allows plotting small data ranges with large offsets: for # example: [1+1e-9,1+2e-9,1+3e-9] useMathText will render the offset # and scientific notation in mathtext if useOffset is None: useOffset = rcParams['axes.formatter.useoffset'] self._offset_threshold = rcParams['axes.formatter.offset_threshold'] self.set_useOffset(useOffset) self._usetex = rcParams['text.usetex'] if useMathText is None: useMathText = rcParams['axes.formatter.use_mathtext'] self.set_useMathText(useMathText) self.orderOfMagnitude = 0 self.format = '' self._scientific = True self._powerlimits = rcParams['axes.formatter.limits'] if useLocale is None: useLocale = rcParams['axes.formatter.use_locale'] self._useLocale = useLocale
[docs] def get_useOffset(self): return self._useOffset
[docs] def set_useOffset(self, val): if val in [True, False]: self.offset = 0 self._useOffset = val else: self._useOffset = False self.offset = val
useOffset = property(fget=get_useOffset, fset=set_useOffset)
[docs] def get_useLocale(self): return self._useLocale
[docs] def set_useLocale(self, val): if val is None: self._useLocale = rcParams['axes.formatter.use_locale'] else: self._useLocale = val
useLocale = property(fget=get_useLocale, fset=set_useLocale)
[docs] def get_useMathText(self): return self._useMathText
[docs] def set_useMathText(self, val): if val is None: self._useMathText = rcParams['axes.formatter.use_mathtext'] else: self._useMathText = val
useMathText = property(fget=get_useMathText, fset=set_useMathText)
[docs] def fix_minus(self, s): """ Replace hyphens with a unicode minus. """ if rcParams['text.usetex'] or not rcParams['axes.unicode_minus']: return s else: return s.replace('-', '\N{MINUS SIGN}')
def __call__(self, x, pos=None): """ Return the format for tick value `x` at position `pos`. """ if len(self.locs) == 0: return '' else: xp = (x - self.offset) / (10. ** self.orderOfMagnitude) if np.abs(xp) < 1e-8: xp = 0 if self._useLocale: s = locale.format_string(self.format, (xp,)) else: s = self.format % xp return self.fix_minus(s)
[docs] def set_scientific(self, b): """ Turn scientific notation on or off. See Also -------- ScalarFormatter.set_powerlimits """ self._scientific = bool(b)
[docs] def set_powerlimits(self, lims): """ Sets size thresholds for scientific notation. Parameters ---------- lims : (min_exp, max_exp) A tuple containing the powers of 10 that determine the switchover threshold. Numbers below ``10**min_exp`` and above ``10**max_exp`` will be displayed in scientific notation. For example, ``formatter.set_powerlimits((-3, 4))`` sets the pre-2007 default in which scientific notation is used for numbers less than 1e-3 or greater than 1e4. See Also -------- ScalarFormatter.set_scientific """ if len(lims) != 2: raise ValueError("'lims' must be a sequence of length 2") self._powerlimits = lims
[docs] def format_data_short(self, value): """ Return a short formatted string representation of a number. """ if self._useLocale: return locale.format_string('%-12g', (value,)) else: return '%-12g' % value
[docs] def format_data(self, value): """ Return a formatted string representation of a number. """ if self._useLocale: s = locale.format_string('%1.10e', (value,)) else: s = '%1.10e' % value s = self._formatSciNotation(s) return self.fix_minus(s)
[docs] def get_offset(self): """ Return scientific notation, plus offset. """ if len(self.locs) == 0: return '' s = '' if self.orderOfMagnitude or self.offset: offsetStr = '' sciNotStr = '' if self.offset: offsetStr = self.format_data(self.offset) if self.offset > 0: offsetStr = '+' + offsetStr if self.orderOfMagnitude: if self._usetex or self._useMathText: sciNotStr = self.format_data(10 ** self.orderOfMagnitude) else: sciNotStr = '1e%d' % self.orderOfMagnitude if self._useMathText: if sciNotStr != '': sciNotStr = r'\times%s' % _mathdefault(sciNotStr) s = ''.join(('$', sciNotStr, _mathdefault(offsetStr), '$')) elif self._usetex: if sciNotStr != '': sciNotStr = r'\times%s' % sciNotStr s = ''.join(('$', sciNotStr, offsetStr, '$')) else: s = ''.join((sciNotStr, offsetStr)) return self.fix_minus(s)
[docs] def set_locs(self, locs): """ Set the locations of the ticks. """ self.locs = locs if len(self.locs) > 0: if self._useOffset: self._compute_offset() self._set_order_of_magnitude() self._set_format()
def _compute_offset(self): locs = self.locs # Restrict to visible ticks. vmin, vmax = sorted(self.axis.get_view_interval()) locs = np.asarray(locs) locs = locs[(vmin <= locs) & (locs <= vmax)] if not len(locs): self.offset = 0 return lmin, lmax = locs.min(), locs.max() # Only use offset if there are at least two ticks and every tick has # the same sign. if lmin == lmax or lmin <= 0 <= lmax: self.offset = 0 return # min, max comparing absolute values (we want division to round towards # zero so we work on absolute values). abs_min, abs_max = sorted([abs(float(lmin)), abs(float(lmax))]) sign = math.copysign(1, lmin) # What is the smallest power of ten such that abs_min and abs_max are # equal up to that precision? # Note: Internally using oom instead of 10 ** oom avoids some numerical # accuracy issues. oom_max = np.ceil(math.log10(abs_max)) oom = 1 + next(oom for oom in itertools.count(oom_max, -1) if abs_min // 10 ** oom != abs_max // 10 ** oom) if (abs_max - abs_min) / 10 ** oom <= 1e-2: # Handle the case of straddling a multiple of a large power of ten # (relative to the span). # What is the smallest power of ten such that abs_min and abs_max # are no more than 1 apart at that precision? oom = 1 + next(oom for oom in itertools.count(oom_max, -1) if abs_max // 10 ** oom - abs_min // 10 ** oom > 1) # Only use offset if it saves at least _offset_threshold digits. n = self._offset_threshold - 1 self.offset = (sign * (abs_max // 10 ** oom) * 10 ** oom if abs_max // 10 ** oom >= 10**n else 0) def _set_order_of_magnitude(self): # if scientific notation is to be used, find the appropriate exponent # if using an numerical offset, find the exponent after applying the # offset. When lower power limit = upper <> 0, use provided exponent. if not self._scientific: self.orderOfMagnitude = 0 return if self._powerlimits[0] == self._powerlimits[1] != 0: # fixed scaling when lower power limit = upper <> 0. self.orderOfMagnitude = self._powerlimits[0] return # restrict to visible ticks vmin, vmax = sorted(self.axis.get_view_interval()) locs = np.asarray(self.locs) locs = locs[(vmin <= locs) & (locs <= vmax)] locs = np.abs(locs) if not len(locs): self.orderOfMagnitude = 0 return if self.offset: oom = math.floor(math.log10(vmax - vmin)) else: if locs[0] > locs[-1]: val = locs[0] else: val = locs[-1] if val == 0: oom = 0 else: oom = math.floor(math.log10(val)) if oom <= self._powerlimits[0]: self.orderOfMagnitude = oom elif oom >= self._powerlimits[1]: self.orderOfMagnitude = oom else: self.orderOfMagnitude = 0 def _set_format(self): # set the format string to format all the ticklabels if len(self.locs) < 2: # Temporarily augment the locations with the axis end points. _locs = [*self.locs, *self.axis.get_view_interval()] else: _locs = self.locs locs = (np.asarray(_locs) - self.offset) / 10. ** self.orderOfMagnitude loc_range = np.ptp(locs) # Curvilinear coordinates can yield two identical points. if loc_range == 0: loc_range = np.max(np.abs(locs)) # Both points might be zero. if loc_range == 0: loc_range = 1 if len(self.locs) < 2: # We needed the end points only for the loc_range calculation. locs = locs[:-2] loc_range_oom = int(math.floor(math.log10(loc_range))) # first estimate: sigfigs = max(0, 3 - loc_range_oom) # refined estimate: thresh = 1e-3 * 10 ** loc_range_oom while sigfigs >= 0: if np.abs(locs - np.round(locs, decimals=sigfigs)).max() < thresh: sigfigs -= 1 else: break sigfigs += 1 self.format = '%1.' + str(sigfigs) + 'f' if self._usetex: self.format = '$%s$' % self.format elif self._useMathText: self.format = '$%s$' % _mathdefault(self.format)
[docs] @cbook.deprecated("3.1") def pprint_val(self, x): xp = (x - self.offset) / (10. ** self.orderOfMagnitude) if np.abs(xp) < 1e-8: xp = 0 if self._useLocale: return locale.format_string(self.format, (xp,)) else: return self.format % xp
def _formatSciNotation(self, s): # transform 1e+004 into 1e4, for example if self._useLocale: decimal_point = locale.localeconv()['decimal_point'] positive_sign = locale.localeconv()['positive_sign'] else: decimal_point = '.' positive_sign = '+' tup = s.split('e') try: significand = tup[0].rstrip('0').rstrip(decimal_point) sign = tup[1][0].replace(positive_sign, '') exponent = tup[1][1:].lstrip('0') if self._useMathText or self._usetex: if significand == '1' and exponent != '': # reformat 1x10^y as 10^y significand = '' if exponent: exponent = '10^{%s%s}' % (sign, exponent) if significand and exponent: return r'%s{\times}%s' % (significand, exponent) else: return r'%s%s' % (significand, exponent) else: s = ('%se%s%s' % (significand, sign, exponent)).rstrip('e') return s except IndexError: return s
[docs]class LogFormatter(Formatter): """ Base class for formatting ticks on a log or symlog scale. It may be instantiated directly, or subclassed. Parameters ---------- base : float, optional, default: 10. Base of the logarithm used in all calculations. labelOnlyBase : bool, optional, default: False If True, label ticks only at integer powers of base. This is normally True for major ticks and False for minor ticks. minor_thresholds : (subset, all), optional, default: (1, 0.4) If labelOnlyBase is False, these two numbers control the labeling of ticks that are not at integer powers of base; normally these are the minor ticks. The controlling parameter is the log of the axis data range. In the typical case where base is 10 it is the number of decades spanned by the axis, so we can call it 'numdec'. If ``numdec <= all``, all minor ticks will be labeled. If ``all < numdec <= subset``, then only a subset of minor ticks will be labeled, so as to avoid crowding. If ``numdec > subset`` then no minor ticks will be labeled. linthresh : None or float, optional, default: None If a symmetric log scale is in use, its ``linthresh`` parameter must be supplied here. Notes ----- The `set_locs` method must be called to enable the subsetting logic controlled by the ``minor_thresholds`` parameter. In some cases such as the colorbar, there is no distinction between major and minor ticks; the tick locations might be set manually, or by a locator that puts ticks at integer powers of base and at intermediate locations. For this situation, disable the minor_thresholds logic by using ``minor_thresholds=(np.inf, np.inf)``, so that all ticks will be labeled. To disable labeling of minor ticks when 'labelOnlyBase' is False, use ``minor_thresholds=(0, 0)``. This is the default for the "classic" style. Examples -------- To label a subset of minor ticks when the view limits span up to 2 decades, and all of the ticks when zoomed in to 0.5 decades or less, use ``minor_thresholds=(2, 0.5)``. To label all minor ticks when the view limits span up to 1.5 decades, use ``minor_thresholds=(1.5, 1.5)``. """ def __init__(self, base=10.0, labelOnlyBase=False, minor_thresholds=None, linthresh=None): self._base = float(base) self.labelOnlyBase = labelOnlyBase if minor_thresholds is None: if rcParams['_internal.classic_mode']: minor_thresholds = (0, 0) else: minor_thresholds = (1, 0.4) self.minor_thresholds = minor_thresholds self._sublabels = None self._linthresh = linthresh
[docs] def base(self, base): """ Change the *base* for labeling. .. warning:: Should always match the base used for :class:`LogLocator` """ self._base = base
[docs] def label_minor(self, labelOnlyBase): """ Switch minor tick labeling on or off. Parameters ---------- labelOnlyBase : bool If True, label ticks only at integer powers of base. """ self.labelOnlyBase = labelOnlyBase
[docs] def set_locs(self, locs=None): """ Use axis view limits to control which ticks are labeled. The *locs* parameter is ignored in the present algorithm. """ if np.isinf(self.minor_thresholds[0]): self._sublabels = None return # Handle symlog case: linthresh = self._linthresh if linthresh is None: try: linthresh = self.axis.get_transform().linthresh except AttributeError: pass vmin, vmax = self.axis.get_view_interval() if vmin > vmax: vmin, vmax = vmax, vmin if linthresh is None and vmin <= 0: # It's probably a colorbar with # a format kwarg setting a LogFormatter in the manner # that worked with 1.5.x, but that doesn't work now. self._sublabels = {1} # label powers of base return b = self._base if linthresh is not None: # symlog # Only compute the number of decades in the logarithmic part of the # axis numdec = 0 if vmin < -linthresh: rhs = min(vmax, -linthresh) numdec += math.log(vmin / rhs) / math.log(b) if vmax > linthresh: lhs = max(vmin, linthresh) numdec += math.log(vmax / lhs) / math.log(b) else: vmin = math.log(vmin) / math.log(b) vmax = math.log(vmax) / math.log(b) numdec = abs(vmax - vmin) if numdec > self.minor_thresholds[0]: # Label only bases self._sublabels = {1} elif numdec > self.minor_thresholds[1]: # Add labels between bases at log-spaced coefficients; # include base powers in case the locations include # "major" and "minor" points, as in colorbar. c = np.logspace(0, 1, int(b)//2 + 1, base=b) self._sublabels = set(np.round(c)) # For base 10, this yields (1, 2, 3, 4, 6, 10). else: # Label all integer multiples of base**n. self._sublabels = set(np.arange(1, b + 1))
def _num_to_string(self, x, vmin, vmax): if x > 10000: s = '%1.0e' % x elif x < 1: s = '%1.0e' % x else: s = self._pprint_val(x, vmax - vmin) return s def __call__(self, x, pos=None): """ Return the format for tick val *x*. """ if x == 0.0: # Symlog return '0' x = abs(x) b = self._base # only label the decades fx = math.log(x) / math.log(b) is_x_decade = is_close_to_int(fx) exponent = np.round(fx) if is_x_decade else np.floor(fx) coeff = np.round(x / b ** exponent) if self.labelOnlyBase and not is_x_decade: return '' if self._sublabels is not None and coeff not in self._sublabels: return '' vmin, vmax = self.axis.get_view_interval() vmin, vmax = mtransforms.nonsingular(vmin, vmax, expander=0.05) s = self._num_to_string(x, vmin, vmax) return self.fix_minus(s)
[docs] def format_data(self, value): b = self.labelOnlyBase self.labelOnlyBase = False value = cbook.strip_math(self.__call__(value)) self.labelOnlyBase = b return value
[docs] def format_data_short(self, value): """ Return a short formatted string representation of a number. """ return '%-12g' % value
[docs] @cbook.deprecated("3.1") def pprint_val(self, *args, **kwargs): return self._pprint_val(*args, **kwargs)
def _pprint_val(self, x, d): # If the number is not too big and it's an int, format it as an int. if abs(x) < 1e4 and x == int(x): return '%d' % x fmt = ('%1.3e' if d < 1e-2 else '%1.3f' if d <= 1 else '%1.2f' if d <= 10 else '%1.1f' if d <= 1e5 else '%1.1e') s = fmt % x tup = s.split('e') if len(tup) == 2: mantissa = tup[0].rstrip('0').rstrip('.') exponent = int(tup[1]) if exponent: s = '%se%d' % (mantissa, exponent) else: s = mantissa else: s = s.rstrip('0').rstrip('.') return s
[docs]class LogFormatterExponent(LogFormatter): """ Format values for log axis using ``exponent = log_base(value)``. """ def _num_to_string(self, x, vmin, vmax): fx = math.log(x) / math.log(self._base) if abs(fx) > 10000: s = '%1.0g' % fx elif abs(fx) < 1: s = '%1.0g' % fx else: fd = math.log(vmax - vmin) / math.log(self._base) s = self._pprint_val(fx, fd) return s
[docs]class LogFormatterMathtext(LogFormatter): """ Format values for log axis using ``exponent = log_base(value)``. """ def _non_decade_format(self, sign_string, base, fx, usetex): 'Return string for non-decade locations' if usetex: return (r'$%s%s^{%.2f}$') % (sign_string, base, fx) else: return ('$%s$' % _mathdefault('%s%s^{%.2f}' % (sign_string, base, fx))) def __call__(self, x, pos=None): """ Return the format for tick value *x*. The position *pos* is ignored. """ usetex = rcParams['text.usetex'] min_exp = rcParams['axes.formatter.min_exponent'] if x == 0: # Symlog if usetex: return '$0$' else: return '$%s$' % _mathdefault('0') sign_string = '-' if x < 0 else '' x = abs(x) b = self._base # only label the decades fx = math.log(x) / math.log(b) is_x_decade = is_close_to_int(fx) exponent = np.round(fx) if is_x_decade else np.floor(fx) coeff = np.round(x / b ** exponent) if is_x_decade: fx = round(fx) if self.labelOnlyBase and not is_x_decade: return '' if self._sublabels is not None and coeff not in self._sublabels: return '' # use string formatting of the base if it is not an integer if b % 1 == 0.0: base = '%d' % b else: base = '%s' % b if np.abs(fx) < min_exp: if usetex: return r'${0}{1:g}$'.format(sign_string, x) else: return '${0}$'.format(_mathdefault( '{0}{1:g}'.format(sign_string, x))) elif not is_x_decade: return self._non_decade_format(sign_string, base, fx, usetex) elif usetex: return r'$%s%s^{%d}$' % (sign_string, base, fx) else: return '$%s$' % _mathdefault('%s%s^{%d}' % (sign_string, base, fx))
[docs]class LogFormatterSciNotation(LogFormatterMathtext): """ Format values following scientific notation in a logarithmic axis. """ def _non_decade_format(self, sign_string, base, fx, usetex): 'Return string for non-decade locations' b = float(base) exponent = math.floor(fx) coeff = b ** fx / b ** exponent if is_close_to_int(coeff): coeff = round(coeff) if usetex: return (r'$%s%g\times%s^{%d}$') % \ (sign_string, coeff, base, exponent) else: return ('$%s$' % _mathdefault(r'%s%g\times%s^{%d}' % (sign_string, coeff, base, exponent)))
[docs]class LogitFormatter(Formatter): """ Probability formatter (using Math text). """ def __call__(self, x, pos=None): s = '' if 0.01 <= x <= 0.99: s = '{:.2f}'.format(x) elif x < 0.01: if is_decade(x): s = '$10^{{{:.0f}}}$'.format(np.log10(x)) else: s = '${:.5f}$'.format(x) else: # x > 0.99 if is_decade(1-x): s = '$1-10^{{{:.0f}}}$'.format(np.log10(1-x)) else: s = '$1-{:.5f}$'.format(1-x) return s
[docs] def format_data_short(self, value): 'return a short formatted string representation of a number' return '%-12g' % value
[docs]class EngFormatter(Formatter): """ Formats axis values using engineering prefixes to represent powers of 1000, plus a specified unit, e.g., 10 MHz instead of 1e7. """ # The SI engineering prefixes ENG_PREFIXES = { -24: "y", -21: "z", -18: "a", -15: "f", -12: "p", -9: "n", -6: "\N{MICRO SIGN}", -3: "m", 0: "", 3: "k", 6: "M", 9: "G", 12: "T", 15: "P", 18: "E", 21: "Z", 24: "Y" } def __init__(self, unit="", places=None, sep=" ", *, usetex=None, useMathText=None): """ Parameters ---------- unit : str (default: "") Unit symbol to use, suitable for use with single-letter representations of powers of 1000. For example, 'Hz' or 'm'. places : int (default: None) Precision with which to display the number, specified in digits after the decimal point (there will be between one and three digits before the decimal point). If it is None, the formatting falls back to the floating point format '%g', which displays up to 6 *significant* digits, i.e. the equivalent value for *places* varies between 0 and 5 (inclusive). sep : str (default: " ") Separator used between the value and the prefix/unit. For example, one get '3.14 mV' if ``sep`` is " " (default) and '3.14mV' if ``sep`` is "". Besides the default behavior, some other useful options may be: * ``sep=""`` to append directly the prefix/unit to the value; * ``sep="\\N{THIN SPACE}"`` (``U+2009``); * ``sep="\\N{NARROW NO-BREAK SPACE}"`` (``U+202F``); * ``sep="\\N{NO-BREAK SPACE}"`` (``U+00A0``). usetex : bool (default: None) To enable/disable the use of TeX's math mode for rendering the numbers in the formatter. useMathText : bool (default: None) To enable/disable the use mathtext for rendering the numbers in the formatter. """ self.unit = unit self.places = places self.sep = sep self.set_usetex(usetex) self.set_useMathText(useMathText)
[docs] def get_usetex(self): return self._usetex
[docs] def set_usetex(self, val): if val is None: self._usetex = rcParams['text.usetex'] else: self._usetex = val
usetex = property(fget=get_usetex, fset=set_usetex)
[docs] def get_useMathText(self): return self._useMathText
[docs] def set_useMathText(self, val): if val is None: self._useMathText = rcParams['axes.formatter.use_mathtext'] else: self._useMathText = val
useMathText = property(fget=get_useMathText, fset=set_useMathText)
[docs] def fix_minus(self, s): """ Replace hyphens with a unicode minus. """ return ScalarFormatter.fix_minus(self, s)
def __call__(self, x, pos=None): s = "%s%s" % (self.format_eng(x), self.unit) # Remove the trailing separator when there is neither prefix nor unit if self.sep and s.endswith(self.sep): s = s[:-len(self.sep)] return self.fix_minus(s)
[docs] def format_eng(self, num): """ Formats a number in engineering notation, appending a letter representing the power of 1000 of the original number. Some examples: >>> format_eng(0) # for self.places = 0 '0' >>> format_eng(1000000) # for self.places = 1 '1.0 M' >>> format_eng("-1e-6") # for self.places = 2 '-1.00 \N{MICRO SIGN}' """ sign = 1 fmt = "g" if self.places is None else ".{:d}f".format(self.places) if num < 0: sign = -1 num = -num if num != 0: pow10 = int(math.floor(math.log10(num) / 3) * 3) else: pow10 = 0 # Force num to zero, to avoid inconsistencies like # format_eng(-0) = "0" and format_eng(0.0) = "0" # but format_eng(-0.0) = "-0.0" num = 0.0 pow10 = np.clip(pow10, min(self.ENG_PREFIXES), max(self.ENG_PREFIXES)) mant = sign * num / (10.0 ** pow10) # Taking care of the cases like 999.9..., which may be rounded to 1000 # instead of 1 k. Beware of the corner case of values that are beyond # the range of SI prefixes (i.e. > 'Y'). if (abs(float(format(mant, fmt))) >= 1000 and pow10 < max(self.ENG_PREFIXES)): mant /= 1000 pow10 += 3 prefix = self.ENG_PREFIXES[int(pow10)] if self._usetex or self._useMathText: formatted = "${mant:{fmt}}${sep}{prefix}".format( mant=mant, sep=self.sep, prefix=prefix, fmt=fmt) else: formatted = "{mant:{fmt}}{sep}{prefix}".format( mant=mant, sep=self.sep, prefix=prefix, fmt=fmt) return formatted
[docs]class PercentFormatter(Formatter): """ Format numbers as a percentage. Parameters ---------- xmax : float Determines how the number is converted into a percentage. *xmax* is the data value that corresponds to 100%. Percentages are computed as ``x / xmax * 100``. So if the data is already scaled to be percentages, *xmax* will be 100. Another common situation is where `xmax` is 1.0. decimals : None or int The number of decimal places to place after the point. If *None* (the default), the number will be computed automatically. symbol : string or None A string that will be appended to the label. It may be *None* or empty to indicate that no symbol should be used. LaTeX special characters are escaped in *symbol* whenever latex mode is enabled, unless *is_latex* is *True*. is_latex : bool If *False*, reserved LaTeX characters in *symbol* will be escaped. """ def __init__(self, xmax=100, decimals=None, symbol='%', is_latex=False): self.xmax = xmax + 0.0 self.decimals = decimals self._symbol = symbol self._is_latex = is_latex def __call__(self, x, pos=None): """ Formats the tick as a percentage with the appropriate scaling. """ ax_min, ax_max = self.axis.get_view_interval() display_range = abs(ax_max - ax_min) return self.fix_minus(self.format_pct(x, display_range))
[docs] def format_pct(self, x, display_range): """ Formats the number as a percentage number with the correct number of decimals and adds the percent symbol, if any. If `self.decimals` is `None`, the number of digits after the decimal point is set based on the `display_range` of the axis as follows: +---------------+----------+------------------------+ | display_range | decimals | sample | +---------------+----------+------------------------+ | >50 | 0 | ``x = 34.5`` => 35% | +---------------+----------+------------------------+ | >5 | 1 | ``x = 34.5`` => 34.5% | +---------------+----------+------------------------+ | >0.5 | 2 | ``x = 34.5`` => 34.50% | +---------------+----------+------------------------+ | ... | ... | ... | +---------------+----------+------------------------+ This method will not be very good for tiny axis ranges or extremely large ones. It assumes that the values on the chart are percentages displayed on a reasonable scale. """ x = self.convert_to_pct(x) if self.decimals is None: # conversion works because display_range is a difference scaled_range = self.convert_to_pct(display_range) if scaled_range <= 0: decimals = 0 else: # Luckily Python's built-in ceil rounds to +inf, not away from # zero. This is very important since the equation for decimals # starts out as `scaled_range > 0.5 * 10**(2 - decimals)` # and ends up with `decimals > 2 - log10(2 * scaled_range)`. decimals = math.ceil(2.0 - math.log10(2.0 * scaled_range)) if decimals > 5: decimals = 5 elif decimals < 0: decimals = 0 else: decimals = self.decimals s = '{x:0.{decimals}f}'.format(x=x, decimals=int(decimals)) return s + self.symbol
[docs] def convert_to_pct(self, x): return 100.0 * (x / self.xmax)
@property def symbol(self): """ The configured percent symbol as a string. If LaTeX is enabled via :rc:`text.usetex`, the special characters ``{'#', '$', '%', '&', '~', '_', '^', '\\', '{', '}'}`` are automatically escaped in the string. """ symbol = self._symbol if not symbol: symbol = '' elif rcParams['text.usetex'] and not self._is_latex: # Source: http://www.personal.ceu.hu/tex/specchar.htm # Backslash must be first for this to work correctly since # it keeps getting added in for spec in r'\#$%&~_^{}': symbol = symbol.replace(spec, '\\' + spec) return symbol @symbol.setter def symbol(self, symbol): self._symbol = symbol
[docs]class Locator(TickHelper): """ Determine the tick locations; Note that the same locator should not be used across multiple `~matplotlib.axis.Axis` because the locator stores references to the Axis data and view limits. """ # Some automatic tick locators can generate so many ticks they # kill the machine when you try and render them. # This parameter is set to cause locators to raise an error if too # many ticks are generated. MAXTICKS = 1000
[docs] def tick_values(self, vmin, vmax): """ Return the values of the located ticks given **vmin** and **vmax**. .. note:: To get tick locations with the vmin and vmax values defined automatically for the associated :attr:`axis` simply call the Locator instance:: >>> print(type(loc)) <type 'Locator'> >>> print(loc()) [1, 2, 3, 4] """ raise NotImplementedError('Derived must override')
[docs] def set_params(self, **kwargs): """ Do nothing, and raise a warning. Any locator class not supporting the set_params() function will call this. """ cbook._warn_external( "'set_params()' not defined for locator of type " + str(type(self)))
def __call__(self): """Return the locations of the ticks""" # note: some locators return data limits, other return view limits, # hence there is no *one* interface to call self.tick_values. raise NotImplementedError('Derived must override')
[docs] def raise_if_exceeds(self, locs): """raise a RuntimeError if Locator attempts to create more than MAXTICKS locs""" if len(locs) >= self.MAXTICKS: raise RuntimeError("Locator attempting to generate {} ticks from " "{} to {}: exceeds Locator.MAXTICKS".format( len(locs), locs[0], locs[-1])) return locs
[docs] def nonsingular(self, v0, v1): """Expand a range as needed to avoid singularities.""" return mtransforms.nonsingular(v0, v1, expander=.05)
[docs] def view_limits(self, vmin, vmax): """ Select a scale for the range from vmin to vmax. Subclasses should override this method to change locator behaviour. """ return mtransforms.nonsingular(vmin, vmax)
[docs] def autoscale(self): """autoscale the view limits""" return self.view_limits(*self.axis.get_view_interval())
[docs] def pan(self, numsteps): """Pan numticks (can be positive or negative)""" ticks = self() numticks = len(ticks) vmin, vmax = self.axis.get_view_interval() vmin, vmax = mtransforms.nonsingular(vmin, vmax, expander=0.05) if numticks > 2: step = numsteps * abs(ticks[0] - ticks[1]) else: d = abs(vmax - vmin) step = numsteps * d / 6. vmin += step vmax += step self.axis.set_view_interval(vmin, vmax, ignore=True)
[docs] def zoom(self, direction): "Zoom in/out on axis; if direction is >0 zoom in, else zoom out" vmin, vmax = self.axis.get_view_interval() vmin, vmax = mtransforms.nonsingular(vmin, vmax, expander=0.05) interval = abs(vmax - vmin) step = 0.1 * interval * direction self.axis.set_view_interval(vmin + step, vmax - step, ignore=True)
[docs] def refresh(self): """refresh internal information based on current lim""" pass
[docs]class IndexLocator(Locator): """ Place a tick on every multiple of some base number of points plotted, e.g., on every 5th point. It is assumed that you are doing index plotting; i.e., the axis is 0, len(data). This is mainly useful for x ticks. """ def __init__(self, base, offset): 'place ticks on the i-th data points where (i-offset)%base==0' self._base = base self.offset = offset
[docs] def set_params(self, base=None, offset=None): """Set parameters within this locator""" if base is not None: self._base = base if offset is not None: self.offset = offset
def __call__(self): """Return the locations of the ticks""" dmin, dmax = self.axis.get_data_interval() return self.tick_values(dmin, dmax)
[docs] def tick_values(self, vmin, vmax): return self.raise_if_exceeds( np.arange(vmin + self.offset, vmax + 1, self._base))
[docs]class FixedLocator(Locator): """ Tick locations are fixed. If nbins is not None, the array of possible positions will be subsampled to keep the number of ticks <= nbins +1. The subsampling will be done so as to include the smallest absolute value; for example, if zero is included in the array of possibilities, then it is guaranteed to be one of the chosen ticks. """ def __init__(self, locs, nbins=None): self.locs = np.asarray(locs) self.nbins = max(nbins, 2) if nbins is not None else None
[docs] def set_params(self, nbins=None): """Set parameters within this locator.""" if nbins is not None: self.nbins = nbins
def __call__(self): return self.tick_values(None, None)
[docs] def tick_values(self, vmin, vmax): """" Return the locations of the ticks. .. note:: Because the values are fixed, vmin and vmax are not used in this method. """ if self.nbins is None: return self.locs step = max(int(np.ceil(len(self.locs) / self.nbins)), 1) ticks = self.locs[::step] for i in range(1, step): ticks1 = self.locs[i::step] if np.abs(ticks1).min() < np.abs(ticks).min(): ticks = ticks1 return self.raise_if_exceeds(ticks)
[docs]class NullLocator(Locator): """ No ticks """ def __call__(self): return self.tick_values(None, None)
[docs] def tick_values(self, vmin, vmax): """" Return the locations of the ticks. .. note:: Because the values are Null, vmin and vmax are not used in this method. """ return []
[docs]class LinearLocator(Locator): """ Determine the tick locations The first time this function is called it will try to set the number of ticks to make a nice tick partitioning. Thereafter the number of ticks will be fixed so that interactive navigation will be nice """ def __init__(self, numticks=None, presets=None): """ Use presets to set locs based on lom. A dict mapping vmin, vmax->locs """ self.numticks = numticks if presets is None: self.presets = {} else: self.presets = presets
[docs] def set_params(self, numticks=None, presets=None): """Set parameters within this locator.""" if presets is not None: self.presets = presets if numticks is not None: self.numticks = numticks
def __call__(self): 'Return the locations of the ticks' vmin, vmax = self.axis.get_view_interval() return self.tick_values(vmin, vmax)
[docs] def tick_values(self, vmin, vmax): vmin, vmax = mtransforms.nonsingular(vmin, vmax, expander=0.05) if vmax < vmin: vmin, vmax = vmax, vmin if (vmin, vmax) in self.presets: return self.presets[(vmin, vmax)] if self.numticks is None: self._set_numticks() if self.numticks == 0: return [] ticklocs = np.linspace(vmin, vmax, self.numticks) return self.raise_if_exceeds(ticklocs)
def _set_numticks(self): self.numticks = 11 # todo; be smart here; this is just for dev
[docs] def view_limits(self, vmin, vmax): 'Try to choose the view limits intelligently' if vmax < vmin: vmin, vmax = vmax, vmin if vmin == vmax: vmin -= 1 vmax += 1 if rcParams['axes.autolimit_mode'] == 'round_numbers': exponent, remainder = divmod( math.log10(vmax - vmin), math.log10(max(self.numticks - 1, 1))) exponent -= (remainder < .5) scale = max(self.numticks - 1, 1) ** (-exponent) vmin = math.floor(scale * vmin) / scale vmax = math.ceil(scale * vmax) / scale return mtransforms.nonsingular(vmin, vmax)
@cbook.deprecated("3.0") def closeto(x, y): return abs(x - y) < 1e-10 @cbook.deprecated("3.0") class Base(object): 'this solution has some hacks to deal with floating point inaccuracies' def __init__(self, base): if base <= 0: raise ValueError("'base' must be positive") self._base = base def lt(self, x): 'return the largest multiple of base < x' d, m = divmod(x, self._base) if closeto(m, 0) and not closeto(m / self._base, 1): return (d - 1) * self._base return d * self._base def le(self, x): 'return the largest multiple of base <= x' d, m = divmod(x, self._base) if closeto(m / self._base, 1): # was closeto(m, self._base) #looks like floating point error return (d + 1) * self._base return d * self._base def gt(self, x): 'return the smallest multiple of base > x' d, m = divmod(x, self._base) if closeto(m / self._base, 1): #looks like floating point error return (d + 2) * self._base return (d + 1) * self._base def ge(self, x): 'return the smallest multiple of base >= x' d, m = divmod(x, self._base) if closeto(m, 0) and not closeto(m / self._base, 1): return d * self._base return (d + 1) * self._base def get_base(self): return self._base
[docs]class MultipleLocator(Locator): """ Set a tick on each integer multiple of a base within the view interval. """ def __init__(self, base=1.0): self._edge = _Edge_integer(base, 0)
[docs] def set_params(self, base): """Set parameters within this locator.""" if base is not None: self._edge = _Edge_integer(base, 0)
def __call__(self): 'Return the locations of the ticks' vmin, vmax = self.axis.get_view_interval() return self.tick_values(vmin, vmax)
[docs] def tick_values(self, vmin, vmax): if vmax < vmin: vmin, vmax = vmax, vmin step = self._edge.step vmin = self._edge.ge(vmin) * step n = (vmax - vmin + 0.001 * step) // step locs = vmin - step + np.arange(n + 3) * step return self.raise_if_exceeds(locs)
[docs] def view_limits(self, dmin, dmax): """ Set the view limits to the nearest multiples of base that contain the data. """ if rcParams['axes.autolimit_mode'] == 'round_numbers': vmin = self._edge.le(dmin) * self._edge.step vmax = self._edge.ge(dmax) * self._edge.step if vmin == vmax: vmin -= 1 vmax += 1 else: vmin = dmin vmax = dmax return mtransforms.nonsingular(vmin, vmax)
def scale_range(vmin, vmax, n=1, threshold=100): dv = abs(vmax - vmin) # > 0 as nonsingular is called before. meanv = (vmax + vmin) / 2 if abs(meanv) / dv < threshold: offset = 0 else: offset = math.copysign(10 ** (math.log10(abs(meanv)) // 1), meanv) scale = 10 ** (math.log10(dv / n) // 1) return scale, offset class _Edge_integer: """ Helper for MaxNLocator, MultipleLocator, etc. Take floating point precision limitations into account when calculating tick locations as integer multiples of a step. """ def __init__(self, step, offset): """ *step* is a positive floating-point interval between ticks. *offset* is the offset subtracted from the data limits prior to calculating tick locations. """ if step <= 0: raise ValueError("'step' must be positive") self.step = step self._offset = abs(offset) def closeto(self, ms, edge): # Allow more slop when the offset is large compared to the step. if self._offset > 0: digits = np.log10(self._offset / self.step) tol = max(1e-10, 10 ** (digits - 12)) tol = min(0.4999, tol) else: tol = 1e-10 return abs(ms - edge) < tol def le(self, x): 'Return the largest n: n*step <= x.' d, m = divmod(x, self.step) if self.closeto(m / self.step, 1): return (d + 1) return d def ge(self, x): 'Return the smallest n: n*step >= x.' d, m = divmod(x, self.step) if self.closeto(m / self.step, 0): return d return (d + 1)
[docs]class MaxNLocator(Locator): """ Select no more than N intervals at nice locations. """ default_params = dict(nbins=10, steps=None, integer=False, symmetric=False, prune=None, min_n_ticks=2) def __init__(self, *args, **kwargs): """ Parameters ---------- nbins : int or 'auto', optional, default: 10 Maximum number of intervals; one less than max number of ticks. If the string `'auto'`, the number of bins will be automatically determined based on the length of the axis. steps : array-like, optional Sequence of nice numbers starting with 1 and ending with 10; e.g., [1, 2, 4, 5, 10], where the values are acceptable tick multiples. i.e. for the example, 20, 40, 60 would be an acceptable set of ticks, as would 0.4, 0.6, 0.8, because they are multiples of 2. However, 30, 60, 90 would not be allowed because 3 does not appear in the list of steps. integer : bool, optional, default: False If True, ticks will take only integer values, provided at least `min_n_ticks` integers are found within the view limits. symmetric : bool, optional, default: False If True, autoscaling will result in a range symmetric about zero. prune : {'lower', 'upper', 'both', None}, optional, default: None Remove edge ticks -- useful for stacked or ganged plots where the upper tick of one axes overlaps with the lower tick of the axes above it, primarily when :rc:`axes.autolimit_mode` is ``'round_numbers'``. If ``prune=='lower'``, the smallest tick will be removed. If ``prune == 'upper'``, the largest tick will be removed. If ``prune == 'both'``, the largest and smallest ticks will be removed. If ``prune == None``, no ticks will be removed. min_n_ticks : int, optional, default: 2 Relax *nbins* and *integer* constraints if necessary to obtain this minimum number of ticks. """ if args: if 'nbins' in kwargs: cbook.deprecated("3.1", message='Calling MaxNLocator with positional ' 'and keyword parameter *nbins* is ' 'considered an error and will fail ' 'in future versions of matplotlib.') kwargs['nbins'] = args[0] if len(args) > 1: raise ValueError( "Keywords are required for all arguments except 'nbins'") self.set_params(**{**self.default_params, **kwargs}) @staticmethod def _validate_steps(steps): if not np.iterable(steps): raise ValueError('steps argument must be an increasing sequence ' 'of numbers between 1 and 10 inclusive') steps = np.asarray(steps) if np.any(np.diff(steps) <= 0) or steps[-1] > 10 or steps[0] < 1: raise ValueError('steps argument must be an increasing sequence ' 'of numbers between 1 and 10 inclusive') if steps[0] != 1: steps = np.hstack((1, steps)) if steps[-1] != 10: steps = np.hstack((steps, 10)) return steps @staticmethod def _staircase(steps): # Make an extended staircase within which the needed # step will be found. This is probably much larger # than necessary. flights = (0.1 * steps[:-1], steps, 10 * steps[1]) return np.hstack(flights)
[docs] def set_params(self, **kwargs): """ Set parameters for this locator. Parameters ---------- nbins : int or 'auto', optional see `.MaxNLocator` steps : array-like, optional see `.MaxNLocator` integer : bool, optional see `.MaxNLocator` symmetric : bool, optional see `.MaxNLocator` prune : {'lower', 'upper', 'both', None}, optional see `.MaxNLocator` min_n_ticks : int, optional see `.MaxNLocator` """ if 'nbins' in kwargs: self._nbins = kwargs.pop('nbins') if self._nbins != 'auto': self._nbins = int(self._nbins) if 'symmetric' in kwargs: self._symmetric = kwargs.pop('symmetric') if 'prune' in kwargs: prune = kwargs.pop('prune') if prune is not None and prune not in ['upper', 'lower', 'both']: raise ValueError( "prune must be 'upper', 'lower', 'both', or None") self._prune = prune if 'min_n_ticks' in kwargs: self._min_n_ticks = max(1, kwargs.pop('min_n_ticks')) if 'steps' in kwargs: steps = kwargs.pop('steps') if steps is None: self._steps = np.array([1, 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10]) else: self._steps = self._validate_steps(steps) self._extended_steps = self._staircase(self._steps) if 'integer' in kwargs: self._integer = kwargs.pop('integer') if kwargs: key, _ = kwargs.popitem() cbook.warn_deprecated("3.1", message="MaxNLocator.set_params got an " f"unexpected parameter: {key}")
def _raw_ticks(self, vmin, vmax): """ Generate a list of tick locations including the range *vmin* to *vmax*. In some applications, one or both of the end locations will not be needed, in which case they are trimmed off elsewhere. """ if self._nbins == 'auto': if self.axis is not None: nbins = np.clip(self.axis.get_tick_space(), max(1, self._min_n_ticks - 1), 9) else: nbins = 9 else: nbins = self._nbins scale, offset = scale_range(vmin, vmax, nbins) _vmin = vmin - offset _vmax = vmax - offset raw_step = (_vmax - _vmin) / nbins steps = self._extended_steps * scale if self._integer: # For steps > 1, keep only integer values. igood = (steps < 1) | (np.abs(steps - np.round(steps)) < 0.001) steps = steps[igood] istep = np.nonzero(steps >= raw_step)[0][0] # Classic round_numbers mode may require a larger step. if rcParams['axes.autolimit_mode'] == 'round_numbers': for istep in range(istep, len(steps)): step = steps[istep] best_vmin = (_vmin // step) * step best_vmax = best_vmin + step * nbins if best_vmax >= _vmax: break # This is an upper limit; move to smaller steps if necessary. for istep in reversed(range(istep + 1)): step = steps[istep] if (self._integer and np.floor(_vmax) - np.ceil(_vmin) >= self._min_n_ticks - 1): step = max(1, step) best_vmin = (_vmin // step) * step # Find tick locations spanning the vmin-vmax range, taking into # account degradation of precision when there is a large offset. # The edge ticks beyond vmin and/or vmax are needed for the # "round_numbers" autolimit mode. edge = _Edge_integer(step, offset) low = edge.le(_vmin - best_vmin) high = edge.ge(_vmax - best_vmin) ticks = np.arange(low, high + 1) * step + best_vmin # Count only the ticks that will be displayed. nticks = ((ticks <= _vmax) & (ticks >= _vmin)).sum() if nticks >= self._min_n_ticks: break return ticks + offset def __call__(self): vmin, vmax = self.axis.get_view_interval() return self.tick_values(vmin, vmax)
[docs] def tick_values(self, vmin, vmax): if self._symmetric: vmax = max(abs(vmin), abs(vmax)) vmin = -vmax vmin, vmax = mtransforms.nonsingular( vmin, vmax, expander=1e-13, tiny=1e-14) locs = self._raw_ticks(vmin, vmax) prune = self._prune if prune == 'lower': locs = locs[1:] elif prune == 'upper': locs = locs[:-1] elif prune == 'both': locs = locs[1:-1] return self.raise_if_exceeds(locs)
[docs] def view_limits(self, dmin, dmax): if self._symmetric: dmax = max(abs(dmin), abs(dmax)) dmin = -dmax dmin, dmax = mtransforms.nonsingular( dmin, dmax, expander=1e-12, tiny=1e-13) if rcParams['axes.autolimit_mode'] == 'round_numbers': return self._raw_ticks(dmin, dmax)[[0, -1]] else: return dmin, dmax
@cbook.deprecated("3.1") def decade_down(x, base=10): 'floor x to the nearest lower decade' if x == 0.0: return -base lx = np.floor(np.log(x) / np.log(base)) return base ** lx @cbook.deprecated("3.1") def decade_up(x, base=10): 'ceil x to the nearest higher decade' if x == 0.0: return base lx = np.ceil(np.log(x) / np.log(base)) return base ** lx def nearest_long(x): cbook.warn_deprecated('3.0', removal='3.1', name='`nearest_long`', obj_type='function', alternative='`round`') if x >= 0: return int(x + 0.5) return int(x - 0.5) def is_decade(x, base=10): if not np.isfinite(x): return False if x == 0.0: return True lx = np.log(np.abs(x)) / np.log(base) return is_close_to_int(lx) def _decade_less_equal(x, base): """ Return the largest integer power of *base* that's less or equal to *x*. If *x* is negative, the exponent will be *greater*. """ return (x if x == 0 else -_decade_greater_equal(-x, base) if x < 0 else base ** np.floor(np.log(x) / np.log(base))) def _decade_greater_equal(x, base): """ Return the smallest integer power of *base* that's greater or equal to *x*. If *x* is negative, the exponent will be *smaller*. """ return (x if x == 0 else -_decade_less_equal(-x, base) if x < 0 else base ** np.ceil(np.log(x) / np.log(base))) def _decade_less(x, base): """ Return the largest integer power of *base* that's less than *x*. If *x* is negative, the exponent will be *greater*. """ if x < 0: return -_decade_greater(-x, base) less = _decade_less_equal(x, base) if less == x: less /= base return less def _decade_greater(x, base): """ Return the smallest integer power of *base* that's greater than *x*. If *x* is negative, the exponent will be *smaller*. """ if x < 0: return -_decade_less(-x, base) greater = _decade_greater_equal(x, base) if greater == x: greater *= base return greater def is_close_to_int(x): return abs(x - np.round(x)) < 1e-10
[docs]class LogLocator(Locator): """ Determine the tick locations for log axes """ def __init__(self, base=10.0, subs=(1.0,), numdecs=4, numticks=None): """ Place ticks on the locations : subs[j] * base**i Parameters ---------- subs : None, string, or sequence of float, optional, default (1.0,) Gives the multiples of integer powers of the base at which to place ticks. The default places ticks only at integer powers of the base. The permitted string values are ``'auto'`` and ``'all'``, both of which use an algorithm based on the axis view limits to determine whether and how to put ticks between integer powers of the base. With ``'auto'``, ticks are placed only between integer powers; with ``'all'``, the integer powers are included. A value of None is equivalent to ``'auto'``. """ if numticks is None: if rcParams['_internal.classic_mode']: numticks = 15 else: numticks = 'auto' self.base(base) self.subs(subs) self.numdecs = numdecs self.numticks = numticks
[docs] def set_params(self, base=None, subs=None, numdecs=None, numticks=None): """Set parameters within this locator.""" if base is not None: self.base(base) if subs is not None: self.subs(subs) if numdecs is not None: self.numdecs = numdecs if numticks is not None: self.numticks = numticks
# FIXME: these base and subs functions are contrary to our # usual and desired API.
[docs] def base(self, base): """ set the base of the log scaling (major tick every base**i, i integer) """ self._base = float(base)
[docs] def subs(self, subs): """ set the minor ticks for the log scaling every base**i*subs[j] """ if subs is None: # consistency with previous bad API self._subs = 'auto' elif isinstance(subs, str): if subs not in ('all', 'auto'): raise ValueError("A subs string must be 'all' or 'auto'; " "found '%s'." % subs) self._subs = subs else: self._subs = np.asarray(subs, dtype=float)
def __call__(self): 'Return the locations of the ticks' vmin, vmax = self.axis.get_view_interval() return self.tick_values(vmin, vmax)
[docs] def tick_values(self, vmin, vmax): if self.numticks == 'auto': if self.axis is not None: numticks = np.clip(self.axis.get_tick_space(), 2, 9) else: numticks = 9 else: numticks = self.numticks b = self._base # dummy axis has no axes attribute if hasattr(self.axis, 'axes') and self.axis.axes.name == 'polar': vmax = math.ceil(math.log(vmax) / math.log(b)) decades = np.arange(vmax - self.numdecs, vmax) ticklocs = b ** decades return ticklocs if vmin <= 0.0: if self.axis is not None: vmin = self.axis.get_minpos() if vmin <= 0.0 or not np.isfinite(vmin): raise ValueError( "Data has no positive values, and therefore can not be " "log-scaled.") _log.debug('vmin %s vmax %s', vmin, vmax) if vmax < vmin: vmin, vmax = vmax, vmin log_vmin = math.log(vmin) / math.log(b) log_vmax = math.log(vmax) / math.log(b) numdec = math.floor(log_vmax) - math.ceil(log_vmin) if isinstance(self._subs, str): _first = 2.0 if self._subs == 'auto' else 1.0 if numdec > 10 or b < 3: if self._subs == 'auto': return np.array([]) # no minor or major ticks else: subs = np.array([1.0]) # major ticks else: subs = np.arange(_first, b) else: subs = self._subs # Get decades between major ticks. stride = (max(math.ceil(numdec / (numticks - 1)), 1) if rcParams['_internal.classic_mode'] else (numdec + 1) // numticks + 1) # Does subs include anything other than 1? Essentially a hack to know # whether we're a major or a minor locator. have_subs = len(subs) > 1 or (len(subs) == 1 and subs[0] != 1.0) decades = np.arange(math.floor(log_vmin) - stride, math.ceil(log_vmax) + 2 * stride, stride) if hasattr(self, '_transform'): ticklocs = self._transform.inverted().transform(decades) if have_subs: if stride == 1: ticklocs = np.ravel(np.outer(subs, ticklocs)) else: # No ticklocs if we have >1 decade between major ticks. ticklocs = np.array([]) else: if have_subs: if stride == 1: ticklocs = np.concatenate( [subs * decade_start for decade_start in b ** decades]) else: ticklocs = np.array([]) else: ticklocs = b ** decades _log.debug('ticklocs %r', ticklocs) if (len(subs) > 1 and stride == 1 and ((vmin <= ticklocs) & (ticklocs <= vmax)).sum() <= 1): # If we're a minor locator *that expects at least two ticks per # decade* and the major locator stride is 1 and there's no more # than one minor tick, switch to AutoLocator. return AutoLocator().tick_values(vmin, vmax) else: return self.raise_if_exceeds(ticklocs)
[docs] def view_limits(self, vmin, vmax): 'Try to choose the view limits intelligently' b = self._base vmin, vmax = self.nonsingular(vmin, vmax) if self.axis.axes.name == 'polar': vmax = math.ceil(math.log(vmax) / math.log(b)) vmin = b ** (vmax - self.numdecs) if rcParams['axes.autolimit_mode'] == 'round_numbers': vmin = _decade_less_equal(vmin, self._base) vmax = _decade_greater_equal(vmax, self._base) return vmin, vmax
[docs] def nonsingular(self, vmin, vmax): if not np.isfinite(vmin) or not np.isfinite(vmax): return 1, 10 # initial range, no data plotted yet if vmin > vmax: vmin, vmax = vmax, vmin if vmax <= 0: cbook._warn_external( "Data has no positive values, and therefore cannot be " "log-scaled.") return 1, 10 minpos = self.axis.get_minpos() if not np.isfinite(minpos): minpos = 1e-300 # This should never take effect. if vmin <= 0: vmin = minpos if vmin == vmax: vmin = _decade_less(vmin, self._base) vmax = _decade_greater(vmax, self._base) return vmin, vmax
[docs]class SymmetricalLogLocator(Locator): """ Determine the tick locations for symmetric log axes """ def __init__(self, transform=None, subs=None, linthresh=None, base=None): """ place ticks on the location= base**i*subs[j] """ if transform is not None: self._base = transform.base self._linthresh = transform.linthresh elif linthresh is not None and base is not None: self._base = base self._linthresh = linthresh else: raise ValueError("Either transform, or both linthresh " "and base, must be provided.") if subs is None: self._subs = [1.0] else: self._subs = subs self.numticks = 15
[docs] def set_params(self, subs=None, numticks=None): """Set parameters within this locator.""" if numticks is not None: self.numticks = numticks if subs is not None: self._subs = subs
def __call__(self): 'Return the locations of the ticks' # Note, these are untransformed coordinates vmin, vmax = self.axis.get_view_interval() return self.tick_values(vmin, vmax)
[docs] def tick_values(self, vmin, vmax): b = self._base t = self._linthresh if vmax < vmin: vmin, vmax = vmax, vmin # The domain is divided into three sections, only some of # which may actually be present. # # <======== -t ==0== t ========> # aaaaaaaaa bbbbb ccccccccc # # a) and c) will have ticks at integral log positions. The # number of ticks needs to be reduced if there are more # than self.numticks of them. # # b) has a tick at 0 and only 0 (we assume t is a small # number, and the linear segment is just an implementation # detail and not interesting.) # # We could also add ticks at t, but that seems to usually be # uninteresting. # # "simple" mode is when the range falls entirely within (-t, # t) -- it should just display (vmin, 0, vmax) has_a = has_b = has_c = False if vmin < -t: has_a = True if vmax > -t: has_b = True if vmax > t: has_c = True elif vmin < 0: if vmax > 0: has_b = True if vmax > t: has_c = True else: return [vmin, vmax] elif vmin < t: if vmax > t: has_b = True has_c = True else: return [vmin, vmax] else: has_c = True def get_log_range(lo, hi): lo = np.floor(np.log(lo) / np.log(b)) hi = np.ceil(np.log(hi) / np.log(b)) return lo, hi # First, calculate all the ranges, so we can determine striding if has_a: if has_b: a_range = get_log_range(t, -vmin + 1) else: a_range = get_log_range(-vmax, -vmin + 1) else: a_range = (0, 0) if has_c: if has_b: c_range = get_log_range(t, vmax + 1) else: c_range = get_log_range(vmin, vmax + 1) else: c_range = (0, 0) total_ticks = (a_range[1] - a_range[0]) + (c_range[1] - c_range[0]) if has_b: total_ticks += 1 stride = max(total_ticks // (self.numticks - 1), 1) decades = [] if has_a: decades.extend(-1 * (b ** (np.arange(a_range[0], a_range[1], stride)[::-1]))) if has_b: decades.append(0.0) if has_c: decades.extend(b ** (np.arange(c_range[0], c_range[1], stride))) # Add the subticks if requested if self._subs is None: subs = np.arange(2.0, b) else: subs = np.asarray(self._subs) if len(subs) > 1 or subs[0] != 1.0: ticklocs = [] for decade in decades: if decade == 0: ticklocs.append(decade) else: ticklocs.extend(subs * decade) else: ticklocs = decades return self.raise_if_exceeds(np.array(ticklocs))
[docs] def view_limits(self, vmin, vmax): 'Try to choose the view limits intelligently' b = self._base if vmax < vmin: vmin, vmax = vmax, vmin if rcParams['axes.autolimit_mode'] == 'round_numbers': vmin = _decade_less_equal(vmin, b) vmax = _decade_greater_equal(vmax, b) if vmin == vmax: vmin = _decade_less(vmin, b) vmax = _decade_greater(vmax, b) result = mtransforms.nonsingular(vmin, vmax) return result
[docs]class LogitLocator(Locator): """ Determine the tick locations for logit axes """ def __init__(self, minor=False): """ place ticks on the logit locations """ self.minor = minor
[docs] def set_params(self, minor=None): """Set parameters within this locator.""" if minor is not None: self.minor = minor
def __call__(self): 'Return the locations of the ticks' vmin, vmax = self.axis.get_view_interval() return self.tick_values(vmin, vmax)
[docs] def tick_values(self, vmin, vmax): # dummy axis has no axes attribute if hasattr(self.axis, 'axes') and self.axis.axes.name == 'polar': raise NotImplementedError('Polar axis cannot be logit scaled yet') vmin, vmax = self.nonsingular(vmin, vmax) vmin = np.log10(vmin / (1 - vmin)) vmax = np.log10(vmax / (1 - vmax)) decade_min = np.floor(vmin) decade_max = np.ceil(vmax) # major ticks if not self.minor: ticklocs = [] if decade_min <= -1: expo = np.arange(decade_min, min(0, decade_max + 1)) ticklocs.extend(10**expo) if decade_min <= 0 <= decade_max: ticklocs.append(0.5) if decade_max >= 1: expo = -np.arange(max(1, decade_min), decade_max + 1) ticklocs.extend(1 - 10**expo) # minor ticks else: ticklocs = [] if decade_min <= -2: expo = np.arange(decade_min, min(-1, decade_max)) newticks = np.outer(np.arange(2, 10), 10**expo).ravel() ticklocs.extend(newticks) if decade_min <= 0 <= decade_max: ticklocs.extend([0.2, 0.3, 0.4, 0.6, 0.7, 0.8]) if decade_max >= 2: expo = -np.arange(max(2, decade_min), decade_max + 1) newticks = 1 - np.outer(np.arange(2, 10), 10**expo).ravel() ticklocs.extend(newticks) return self.raise_if_exceeds(np.array(ticklocs))
[docs] def nonsingular(self, vmin, vmax): initial_range = (1e-7, 1 - 1e-7) if not np.isfinite(vmin) or not np.isfinite(vmax): return initial_range # no data plotted yet if vmin > vmax: vmin, vmax = vmax, vmin # what to do if a window beyond ]0, 1[ is chosen if self.axis is not None: minpos = self.axis.get_minpos() if not np.isfinite(minpos): return initial_range # again, no data plotted else: minpos = 1e-7 # should not occur in normal use # NOTE: for vmax, we should query a property similar to get_minpos, but # related to the maximal, less-than-one data point. Unfortunately, # Bbox._minpos is defined very deep in the BBox and updated with data, # so for now we use 1 - minpos as a substitute. if vmin <= 0: vmin = minpos if vmax >= 1: vmax = 1 - minpos if vmin == vmax: return 0.1 * vmin, 1 - 0.1 * vmin return vmin, vmax
[docs]class AutoLocator(MaxNLocator): """ Dynamically find major tick positions. This is actually a subclass of `~matplotlib.ticker.MaxNLocator`, with parameters *nbins = 'auto'* and *steps = [1, 2, 2.5, 5, 10]*. """ def __init__(self): """ To know the values of the non-public parameters, please have a look to the defaults of `~matplotlib.ticker.MaxNLocator`. """ if rcParams['_internal.classic_mode']: nbins = 9 steps = [1, 2, 5, 10] else: nbins = 'auto' steps = [1, 2, 2.5, 5, 10] MaxNLocator.__init__(self, nbins=nbins, steps=steps)
[docs]class AutoMinorLocator(Locator): """ Dynamically find minor tick positions based on the positions of major ticks. The scale must be linear with major ticks evenly spaced. """ def __init__(self, n=None): """ *n* is the number of subdivisions of the interval between major ticks; e.g., n=2 will place a single minor tick midway between major ticks. If *n* is omitted or None, it will be set to 5 or 4. """ self.ndivs = n def __call__(self): 'Return the locations of the ticks' if self.axis.get_scale() == 'log': cbook._warn_external('AutoMinorLocator does not work with ' 'logarithmic scale') return [] majorlocs = self.axis.get_majorticklocs() try: majorstep = majorlocs[1] - majorlocs[0] except IndexError: # Need at least two major ticks to find minor tick locations # TODO: Figure out a way to still be able to display minor # ticks without two major ticks visible. For now, just display # no ticks at all. return [] if self.ndivs is None: majorstep_no_exponent = 10 ** (np.log10(majorstep) % 1) if np.isclose(majorstep_no_exponent, [1.0, 2.5, 5.0, 10.0]).any(): ndivs = 5 else: ndivs = 4 else: ndivs = self.ndivs minorstep = majorstep / ndivs vmin, vmax = self.axis.get_view_interval() if vmin > vmax: vmin, vmax = vmax, vmin t0 = majorlocs[0] tmin = ((vmin - t0) // minorstep + 1) * minorstep tmax = ((vmax - t0) // minorstep + 1) * minorstep locs = np.arange(tmin, tmax, minorstep) + t0 return self.raise_if_exceeds(locs)
[docs] def tick_values(self, vmin, vmax): raise NotImplementedError('Cannot get tick locations for a ' '%s type.' % type(self))
class OldAutoLocator(Locator): """ On autoscale this class picks the best MultipleLocator to set the view limits and the tick locs. """ def __init__(self): self._locator = LinearLocator() def __call__(self): 'Return the locations of the ticks' self.refresh() return self.raise_if_exceeds(self._locator()) def tick_values(self, vmin, vmax): raise NotImplementedError('Cannot get tick locations for a ' '%s type.' % type(self)) def refresh(self): 'refresh internal information based on current lim' vmin, vmax = self.axis.get_view_interval() vmin, vmax = mtransforms.nonsingular(vmin, vmax, expander=0.05) d = abs(vmax - vmin) self._locator = self.get_locator(d) def view_limits(self, vmin, vmax): 'Try to choose the view limits intelligently' d = abs(vmax - vmin) self._locator = self.get_locator(d) return self._locator.view_limits(vmin, vmax) def get_locator(self, d): 'pick the best locator based on a distance' d = abs(d) if d <= 0: locator = MultipleLocator(0.2) else: try: ld = math.log10(d) except OverflowError: raise RuntimeError('AutoLocator illegal data interval range') fld = math.floor(ld) base = 10 ** fld #if ld==fld: base = 10**(fld-1) #else: base = 10**fld if d >= 5 * base: ticksize = base elif d >= 2 * base: ticksize = base / 2.0 else: ticksize = base / 5.0 locator = MultipleLocator(ticksize) return locator