""" Tick locating and formatting ============================ This module contains classes for configuring tick locating and formatting. Generic tick locators and formatters are provided, as well as domain specific custom ones. 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. .. _tick_locating: .. _locators: 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: ======================= ======================================================= `AutoLocator` `MaxNLocator` with simple defaults. This is the default tick locator for most plotting. `MaxNLocator` Finds up to a max number of intervals with ticks at nice locations. `LinearLocator` Space ticks evenly from min to max. `LogLocator` Space ticks logarithmically from min to max. `MultipleLocator` Ticks and range are a multiple of base; either integer or float. `FixedLocator` Tick locations are fixed. `IndexLocator` Locator for index plots (e.g., where ``x = range(len(y))``). `NullLocator` No ticks. `SymmetricalLogLocator` Locator for use with the symlog norm; works like `LogLocator` for the part outside of the threshold and adds 0 if inside the limits. `AsinhLocator` Locator for use with the asinh norm, attempting to space ticks approximately uniformly. `LogitLocator` Locator for logit scaling. `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 :mod:`.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. .. note:: `Locator` instances should not be used with more than one `~matplotlib.axis.Axis` or `~matplotlib.axes.Axes`. So instead of:: locator = MultipleLocator(5) ax.xaxis.set_major_locator(locator) ax2.xaxis.set_major_locator(locator) do the following instead:: ax.xaxis.set_major_locator(MultipleLocator(5)) ax2.xaxis.set_major_locator(MultipleLocator(5)) .. _formatters: 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. ========================= ===================================================== `NullFormatter` No labels on the ticks. `FixedFormatter` Set the strings manually for the labels. `FuncFormatter` User defined function sets the labels. `StrMethodFormatter` Use string `format` method. `FormatStrFormatter` Use an old-style sprintf format string. `ScalarFormatter` Default formatter for scalars: autopick the format string. `LogFormatter` Formatter for log axes. `LogFormatterExponent` Format values for log axis using ``exponent = log_base(value)``. `LogFormatterMathtext` Format values for log axis using ``exponent = log_base(value)`` using Math text. `LogFormatterSciNotation` Format values for log axis using scientific notation. `LogitFormatter` Probability formatter. `EngFormatter` Format labels in engineering notation. `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) In addition to a `.Formatter` instance, `~.Axis.set_major_formatter` and `~.Axis.set_minor_formatter` also accept a ``str`` or function. ``str`` input will be internally replaced with an autogenerated `.StrMethodFormatter` with the input ``str``. For function input, a `.FuncFormatter` with the input function will be generated and used. See :doc:`/gallery/ticks/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 from numbers import Integral import numpy as np import matplotlib as mpl from matplotlib import _api, cbook from matplotlib import transforms as mtransforms _log = logging.getLogger(__name__) __all__ = ('TickHelper', 'Formatter', 'FixedFormatter', 'NullFormatter', 'FuncFormatter', 'FormatStrFormatter', 'StrMethodFormatter', 'ScalarFormatter', 'LogFormatter', 'LogFormatterExponent', 'LogFormatterMathtext', 'LogFormatterSciNotation', 'LogitFormatter', 'EngFormatter', 'PercentFormatter', 'Locator', 'IndexLocator', 'FixedLocator', 'NullLocator', 'LinearLocator', 'LogLocator', 'AutoLocator', 'MultipleLocator', 'MaxNLocator', 'AutoMinorLocator', 'SymmetricalLogLocator', 'AsinhLocator', 'LogitLocator') class _DummyAxis: __name__ = "dummy" def __init__(self, minpos=0): self._data_interval = (0, 1) self._view_interval = (0, 1) self._minpos = minpos def get_view_interval(self): return self._view_interval def set_view_interval(self, vmin, vmax): self._view_interval = (vmin, vmax) def get_minpos(self): return self._minpos def get_data_interval(self): return self._data_interval def set_data_interval(self, vmin, vmax): self._data_interval = (vmin, vmax) def get_tick_space(self): # Just use the long-standing default of nbins==9 return 9 class TickHelper: axis = None def set_axis(self, axis): self.axis = axis def create_dummy_axis(self, **kwargs): if self.axis is None: self.axis = _DummyAxis(**kwargs) 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') 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)] def format_data(self, value): """ Return the full string representation of the value with the position unspecified. """ return self.__call__(value) 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) def get_offset(self): return '' def set_locs(self, locs): """ Set the locations of the ticks. This method is called before computing the tick labels because some formatters need to know all tick locations to do so. """ self.locs = locs @staticmethod def fix_minus(s): """ Some classes may want to replace a hyphen for minus with the proper Unicode symbol (U+2212) for typographical correctness. This is a helper method to perform such a replacement when it is enabled via :rc:`axes.unicode_minus`. """ return (s.replace('-', '\N{MINUS SIGN}') if mpl.rcParams['axes.unicode_minus'] else s) def _set_locator(self, locator): """Subclasses may want to override this to set a locator.""" pass class NullFormatter(Formatter): """Always return the empty string.""" def __call__(self, x, pos=None): # docstring inherited return '' class FixedFormatter(Formatter): """ Return fixed strings for tick labels based only on position, not value. .. note:: `.FixedFormatter` should only be used together with `.FixedLocator`. Otherwise, the labels may end up in unexpected positions. """ def __init__(self, seq): """Set the sequence *seq* of strings that will be used for labels.""" self.seq = seq self.offset_string = '' def __call__(self, x, pos=None): """ Return 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] def get_offset(self): return self.offset_string def set_offset_string(self, ofs): self.offset_string = ofs 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 self.offset_string = "" 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) def get_offset(self): return self.offset_string def set_offset_string(self, ofs): self.offset_string = ofs 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. Negative numeric values will use a dash, not a Unicode minus; use mathtext to get a Unicode minus by wrapping the format specifier with $ (e.g. "$%g$"). """ 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 class StrMethodFormatter(Formatter): """ Use a new-style format string (as used by `str.format`) to format the tick. The field used for the tick value must be labeled *x* and the field used for the tick 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 ScalarFormatter(Formatter): """ Format tick values as a number. Parameters ---------- useOffset : bool or float, default: :rc:`axes.formatter.useoffset` Whether to use offset notation. See `.set_useOffset`. useMathText : bool, default: :rc:`axes.formatter.use_mathtext` Whether to use fancy math formatting. See `.set_useMathText`. useLocale : bool, default: :rc:`axes.formatter.use_locale`. Whether to use locale settings for decimal sign and positive sign. See `.set_useLocale`. Notes ----- In addition to the parameters above, the formatting of scientific vs. floating point representation can be configured via `.set_scientific` and `.set_powerlimits`). **Offset notation and scientific notation** Offset notation and scientific notation look quite similar at first sight. Both split some information from the formatted tick values and display it at the end of the axis. - The scientific notation splits up the order of magnitude, i.e. a multiplicative scaling factor, e.g. ``1e6``. - The offset notation separates an additive constant, e.g. ``+1e6``. The offset notation label is always prefixed with a ``+`` or ``-`` sign and is thus distinguishable from the order of magnitude label. The following plot with x limits ``1_000_000`` to ``1_000_010`` illustrates the different formatting. Note the labels at the right edge of the x axis. .. plot:: lim = (1_000_000, 1_000_010) fig, (ax1, ax2, ax3) = plt.subplots(3, 1, gridspec_kw={'hspace': 2}) ax1.set(title='offset_notation', xlim=lim) ax2.set(title='scientific notation', xlim=lim) ax2.xaxis.get_major_formatter().set_useOffset(False) ax3.set(title='floating point notation', xlim=lim) ax3.xaxis.get_major_formatter().set_useOffset(False) ax3.xaxis.get_major_formatter().set_scientific(False) """ def __init__(self, useOffset=None, useMathText=None, useLocale=None): if useOffset is None: useOffset = mpl.rcParams['axes.formatter.useoffset'] self._offset_threshold = \ mpl.rcParams['axes.formatter.offset_threshold'] self.set_useOffset(useOffset) self._usetex = mpl.rcParams['text.usetex'] self.set_useMathText(useMathText) self.orderOfMagnitude = 0 self.format = '' self._scientific = True self._powerlimits = mpl.rcParams['axes.formatter.limits'] self.set_useLocale(useLocale) def get_useOffset(self): """ Return whether automatic mode for offset notation is active. This returns True if ``set_useOffset(True)``; it returns False if an explicit offset was set, e.g. ``set_useOffset(1000)``. See Also -------- ScalarFormatter.set_useOffset """ return self._useOffset def set_useOffset(self, val): """ Set whether to use offset notation. When formatting a set numbers whose value is large compared to their range, the formatter can separate an additive constant. This can shorten the formatted numbers so that they are less likely to overlap when drawn on an axis. Parameters ---------- val : bool or float - If False, do not use offset notation. - If True (=automatic mode), use offset notation if it can make the residual numbers significantly shorter. The exact behavior is controlled by :rc:`axes.formatter.offset_threshold`. - If a number, force an offset of the given value. Examples -------- With active offset notation, the values ``100_000, 100_002, 100_004, 100_006, 100_008`` will be formatted as ``0, 2, 4, 6, 8`` plus an offset ``+1e5``, which is written to the edge of the axis. """ 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) def get_useLocale(self): """ Return whether locale settings are used for formatting. See Also -------- ScalarFormatter.set_useLocale """ return self._useLocale def set_useLocale(self, val): """ Set whether to use locale settings for decimal sign and positive sign. Parameters ---------- val : bool or None *None* resets to :rc:`axes.formatter.use_locale`. """ if val is None: self._useLocale = mpl.rcParams['axes.formatter.use_locale'] else: self._useLocale = val useLocale = property(fget=get_useLocale, fset=set_useLocale) def _format_maybe_minus_and_locale(self, fmt, arg): """ Format *arg* with *fmt*, applying Unicode minus and locale if desired. """ return self.fix_minus( # Escape commas introduced by locale.format_string if using math text, # but not those present from the beginning in fmt. (",".join(locale.format_string(part, (arg,), True).replace(",", "{,}") for part in fmt.split(",")) if self._useMathText else locale.format_string(fmt, (arg,), True)) if self._useLocale else fmt % arg) def get_useMathText(self): """ Return whether to use fancy math formatting. See Also -------- ScalarFormatter.set_useMathText """ return self._useMathText def set_useMathText(self, val): r""" Set whether to use fancy math formatting. If active, scientific notation is formatted as :math:`1.2 \times 10^3`. Parameters ---------- val : bool or None *None* resets to :rc:`axes.formatter.use_mathtext`. """ if val is None: self._useMathText = mpl.rcParams['axes.formatter.use_mathtext'] if self._useMathText is False: try: from matplotlib import font_manager ufont = font_manager.findfont( font_manager.FontProperties( mpl.rcParams["font.family"] ), fallback_to_default=False, ) except ValueError: ufont = None if ufont == str(cbook._get_data_path("fonts/ttf/cmr10.ttf")): _api.warn_external( "cmr10 font should ideally be used with " "mathtext, set axes.formatter.use_mathtext to True" ) else: self._useMathText = val useMathText = property(fget=get_useMathText, fset=set_useMathText) 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 abs(xp) < 1e-8: xp = 0 return self._format_maybe_minus_and_locale(self.format, xp) def set_scientific(self, b): """ Turn scientific notation on or off. See Also -------- ScalarFormatter.set_powerlimits """ self._scientific = bool(b) def set_powerlimits(self, lims): r""" Set size thresholds for scientific notation. Parameters ---------- lims : (int, int) A tuple *(min_exp, max_exp)* containing the powers of 10 that determine the switchover threshold. For a number representable as :math:`a \times 10^\mathrm{exp}` with :math:`1 <= |a| < 10`, scientific notation will be used if ``exp <= min_exp`` or ``exp >= max_exp``. The default limits are controlled by :rc:`axes.formatter.limits`. In particular numbers with *exp* equal to the thresholds are written in scientific notation. Typically, *min_exp* will be negative and *max_exp* will be positive. For example, ``formatter.set_powerlimits((-3, 4))`` will provide the following formatting: :math:`1 \times 10^{-3}, 9.9 \times 10^{-3}, 0.01,` :math:`9999, 1 \times 10^4`. See Also -------- ScalarFormatter.set_scientific """ if len(lims) != 2: raise ValueError("'lims' must be a sequence of length 2") self._powerlimits = lims def format_data_short(self, value): # docstring inherited if value is np.ma.masked: return "" if isinstance(value, Integral): fmt = "%d" else: if getattr(self.axis, "__name__", "") in ["xaxis", "yaxis"]: if self.axis.__name__ == "xaxis": axis_trf = self.axis.axes.get_xaxis_transform() axis_inv_trf = axis_trf.inverted() screen_xy = axis_trf.transform((value, 0)) neighbor_values = axis_inv_trf.transform( screen_xy + [[-1, 0], [+1, 0]])[:, 0] else: # yaxis: axis_trf = self.axis.axes.get_yaxis_transform() axis_inv_trf = axis_trf.inverted() screen_xy = axis_trf.transform((0, value)) neighbor_values = axis_inv_trf.transform( screen_xy + [[0, -1], [0, +1]])[:, 1] delta = abs(neighbor_values - value).max() else: # Rough approximation: no more than 1e4 divisions. a, b = self.axis.get_view_interval() delta = (b - a) / 1e4 fmt = f"%-#.{cbook._g_sig_digits(value, delta)}g" return self._format_maybe_minus_and_locale(fmt, value) def format_data(self, value): # docstring inherited e = math.floor(math.log10(abs(value))) s = round(value / 10**e, 10) significand = self._format_maybe_minus_and_locale( "%d" if s % 1 == 0 else "%1.10g", s) if e == 0: return significand exponent = self._format_maybe_minus_and_locale("%d", e) if self._useMathText or self._usetex: exponent = "10^{%s}" % exponent return (exponent if s == 1 # reformat 1x10^y as 10^y else rf"{significand} \times {exponent}") else: return f"{significand}e{exponent}" def get_offset(self): """ Return scientific notation, plus offset. """ if len(self.locs) == 0: return '' 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 or self._usetex: if sciNotStr != '': sciNotStr = r'\times\mathdefault{%s}' % sciNotStr s = fr'${sciNotStr}\mathdefault{{{offsetStr}}}$' else: s = ''.join((sciNotStr, offsetStr)) return self.fix_minus(s) return '' def set_locs(self, locs): # docstring inherited 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 a 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: val = locs.max() 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 = f'%1.{sigfigs}f' if self._usetex or self._useMathText: self.format = r'$\mathdefault{%s}$' % self.format class LogFormatter(Formatter): """ Base class for formatting ticks on a log or symlog scale. It may be instantiated directly, or subclassed. Parameters ---------- base : float, default: 10. Base of the logarithm used in all calculations. labelOnlyBase : bool, 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), 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, 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.set_base(base) self.set_label_minor(labelOnlyBase) if minor_thresholds is None: if mpl.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 def set_base(self, base): """ Change the *base* for labeling. .. warning:: Should always match the base used for :class:`LogLocator` """ self._base = float(base) def set_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 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.geomspace(1, b, int(b)//2 + 1) 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): # docstring inherited 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 = round(fx) if is_x_decade else np.floor(fx) coeff = round(b ** (fx - 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) def format_data(self, value): with cbook._setattr_cm(self, labelOnlyBase=False): return cbook.strip_math(self.__call__(value)) def format_data_short(self, value): # docstring inherited return '%-12g' % value 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 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 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.""" return r'$\mathdefault{%s%s^{%.2f}}$' % (sign_string, base, fx) def __call__(self, x, pos=None): # docstring inherited if x == 0: # Symlog return r'$\mathdefault{0}$' 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 = round(fx) if is_x_decade else np.floor(fx) coeff = round(b ** (fx - exponent)) if self.labelOnlyBase and not is_x_decade: return '' if self._sublabels is not None and coeff not in self._sublabels: return '' if is_x_decade: fx = round(fx) # 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 abs(fx) < mpl.rcParams['axes.formatter.min_exponent']: return r'$\mathdefault{%s%g}$' % (sign_string, x) elif not is_x_decade: usetex = mpl.rcParams['text.usetex'] return self._non_decade_format(sign_string, base, fx, usetex) else: return r'$\mathdefault{%s%s^{%d}}$' % (sign_string, base, fx) 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 - exponent) if _is_close_to_int(coeff): coeff = round(coeff) return r'$\mathdefault{%s%g\times%s^{%d}}$' \ % (sign_string, coeff, base, exponent) class LogitFormatter(Formatter): """ Probability formatter (using Math text). """ def __init__( self, *, use_overline=False, one_half=r"\frac{1}{2}", minor=False, minor_threshold=25, minor_number=6, ): r""" Parameters ---------- use_overline : bool, default: False If x > 1/2, with x = 1-v, indicate if x should be displayed as $\overline{v}$. The default is to display $1-v$. one_half : str, default: r"\frac{1}{2}" The string used to represent 1/2. minor : bool, default: False Indicate if the formatter is formatting minor ticks or not. Basically minor ticks are not labelled, except when only few ticks are provided, ticks with most space with neighbor ticks are labelled. See other parameters to change the default behavior. minor_threshold : int, default: 25 Maximum number of locs for labelling some minor ticks. This parameter have no effect if minor is False. minor_number : int, default: 6 Number of ticks which are labelled when the number of ticks is below the threshold. """ self._use_overline = use_overline self._one_half = one_half self._minor = minor self._labelled = set() self._minor_threshold = minor_threshold self._minor_number = minor_number def use_overline(self, use_overline): r""" Switch display mode with overline for labelling p>1/2. Parameters ---------- use_overline : bool, default: False If x > 1/2, with x = 1-v, indicate if x should be displayed as $\overline{v}$. The default is to display $1-v$. """ self._use_overline = use_overline def set_one_half(self, one_half): r""" Set the way one half is displayed. one_half : str, default: r"\frac{1}{2}" The string used to represent 1/2. """ self._one_half = one_half def set_minor_threshold(self, minor_threshold): """ Set the threshold for labelling minors ticks. Parameters ---------- minor_threshold : int Maximum number of locations for labelling some minor ticks. This parameter have no effect if minor is False. """ self._minor_threshold = minor_threshold def set_minor_number(self, minor_number): """ Set the number of minor ticks to label when some minor ticks are labelled. Parameters ---------- minor_number : int Number of ticks which are labelled when the number of ticks is below the threshold. """ self._minor_number = minor_number def set_locs(self, locs): self.locs = np.array(locs) self._labelled.clear() if not self._minor: return None if all( _is_decade(x, rtol=1e-7) or _is_decade(1 - x, rtol=1e-7) or (_is_close_to_int(2 * x) and int(np.round(2 * x)) == 1) for x in locs ): # minor ticks are subsample from ideal, so no label return None if len(locs) < self._minor_threshold: if len(locs) < self._minor_number: self._labelled.update(locs) else: # we do not have a lot of minor ticks, so only few decades are # displayed, then we choose some (spaced) minor ticks to label. # Only minor ticks are known, we assume it is sufficient to # choice which ticks are displayed. # For each ticks we compute the distance between the ticks and # the previous, and between the ticks and the next one. Ticks # with smallest minimum are chosen. As tiebreak, the ticks # with smallest sum is chosen. diff = np.diff(-np.log(1 / self.locs - 1)) space_pessimistic = np.minimum( np.concatenate(((np.inf,), diff)), np.concatenate((diff, (np.inf,))), ) space_sum = ( np.concatenate(((0,), diff)) + np.concatenate((diff, (0,))) ) good_minor = sorted( range(len(self.locs)), key=lambda i: (space_pessimistic[i], space_sum[i]), )[-self._minor_number:] self._labelled.update(locs[i] for i in good_minor) def _format_value(self, x, locs, sci_notation=True): if sci_notation: exponent = math.floor(np.log10(x)) min_precision = 0 else: exponent = 0 min_precision = 1 value = x * 10 ** (-exponent) if len(locs) < 2: precision = min_precision else: diff = np.sort(np.abs(locs - x))[1] precision = -np.log10(diff) + exponent precision = ( int(np.round(precision)) if _is_close_to_int(precision) else math.ceil(precision) ) if precision < min_precision: precision = min_precision mantissa = r"%.*f" % (precision, value) if not sci_notation: return mantissa s = r"%s\cdot10^{%d}" % (mantissa, exponent) return s def _one_minus(self, s): if self._use_overline: return r"\overline{%s}" % s else: return f"1-{s}" def __call__(self, x, pos=None): if self._minor and x not in self._labelled: return "" if x <= 0 or x >= 1: return "" if _is_close_to_int(2 * x) and round(2 * x) == 1: s = self._one_half elif x < 0.5 and _is_decade(x, rtol=1e-7): exponent = round(math.log10(x)) s = "10^{%d}" % exponent elif x > 0.5 and _is_decade(1 - x, rtol=1e-7): exponent = round(math.log10(1 - x)) s = self._one_minus("10^{%d}" % exponent) elif x < 0.1: s = self._format_value(x, self.locs) elif x > 0.9: s = self._one_minus(self._format_value(1-x, 1-self.locs)) else: s = self._format_value(x, self.locs, sci_notation=False) return r"$\mathdefault{%s}$" % s def format_data_short(self, value): # docstring inherited # Thresholds chosen to use scientific notation iff exponent <= -2. if value < 0.1: return f"{value:e}" if value < 0.9: return f"{value:f}" return f"1-{1 - value:e}" class EngFormatter(Formatter): """ Format 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 = { -30: "q", -27: "r", -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", 27: "R", 30: "Q" } def __init__(self, unit="", places=None, sep=" ", *, usetex=None, useMathText=None): r""" 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: :rc:`text.usetex` To enable/disable the use of TeX's math mode for rendering the numbers in the formatter. useMathText : bool, default: :rc:`axes.formatter.use_mathtext` 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) def get_usetex(self): return self._usetex def set_usetex(self, val): if val is None: self._usetex = mpl.rcParams['text.usetex'] else: self._usetex = val usetex = property(fget=get_usetex, fset=set_usetex) def get_useMathText(self): return self._useMathText def set_useMathText(self, val): if val is None: self._useMathText = mpl.rcParams['axes.formatter.use_mathtext'] else: self._useMathText = val useMathText = property(fget=get_useMathText, fset=set_useMathText) def __call__(self, x, pos=None): s = f"{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) def format_eng(self, num): """ Format 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 f".{self.places:d}f" 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 = f"${mant:{fmt}}${self.sep}{prefix}" else: formatted = f"{mant:{fmt}}{self.sep}{prefix}" return formatted 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 : str 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): """Format 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)) def format_pct(self, x, display_range): """ Format 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 = f'{x:0.{int(decimals)}f}' return s + self.symbol def convert_to_pct(self, x): return 100.0 * (x / self.xmax) @property def symbol(self): r""" The configured percent symbol as a string. If LaTeX is enabled via :rc:`text.usetex`, the special characters ``{'#', '$', '%', '&', '~', '_', '^', '\', '{', '}'}`` are automatically escaped in the string. """ symbol = self._symbol if not symbol: symbol = '' elif not self._is_latex and mpl.rcParams['text.usetex']: # Source: http://www.personal.ceu.hu/tex/specchar.htm # Backslash must be first for this to work correctly since # it keeps getting added in for spec in r'\#$%&~_^{}': symbol = symbol.replace(spec, '\\' + spec) return symbol @symbol.setter def symbol(self, symbol): self._symbol = symbol 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 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 ``axis`` simply call the Locator instance:: >>> print(type(loc)) >>> print(loc()) [1, 2, 3, 4] """ raise NotImplementedError('Derived must override') def set_params(self, **kwargs): """ Do nothing, and raise a warning. Any locator class not supporting the set_params() function will call this. """ _api.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') def raise_if_exceeds(self, locs): """ Log at WARNING level if *locs* is longer than `Locator.MAXTICKS`. This is intended to be called immediately before returning *locs* from ``__call__`` to inform users in case their Locator returns a huge number of ticks, causing Matplotlib to run out of memory. The "strange" name of this method dates back to when it would raise an exception instead of emitting a log. """ if len(locs) >= self.MAXTICKS: _log.warning( "Locator attempting to generate %s ticks ([%s, ..., %s]), " "which exceeds Locator.MAXTICKS (%s).", len(locs), locs[0], locs[-1], self.MAXTICKS) return locs def nonsingular(self, v0, v1): """ Adjust a range as needed to avoid singularities. This method gets called during autoscaling, with ``(v0, v1)`` set to the data limits on the axes if the axes contains any data, or ``(-inf, +inf)`` if not. - If ``v0 == v1`` (possibly up to some floating point slop), this method returns an expanded interval around this value. - If ``(v0, v1) == (-inf, +inf)``, this method returns appropriate default view limits. - Otherwise, ``(v0, v1)`` is returned without modification. """ return mtransforms.nonsingular(v0, v1, expander=.05) 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) 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 every *base* data point, starting at *offset*.""" self._base = base self.offset = offset 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) def tick_values(self, vmin, vmax): return self.raise_if_exceeds( np.arange(vmin + self.offset, vmax + 1, self._base)) class FixedLocator(Locator): """ Tick locations are fixed at *locs*. If *nbins* is not None, the *locs* array of possible positions will be subsampled to keep the number of ticks <= *nbins* +1. The subsampling will be done 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) _api.check_shape((None,), locs=self.locs) self.nbins = max(nbins, 2) if nbins is not None else None 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) 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) class NullLocator(Locator): """ No ticks """ def __call__(self): return self.tick_values(None, None) 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 [] 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): """ Parameters ---------- numticks : int or None, default None Number of ticks. If None, *numticks* = 11. presets : dict or None, default: None Dictionary mapping ``(vmin, vmax)`` to an array of locations. Overrides *numticks* if there is an entry for the current ``(vmin, vmax)``. """ self.numticks = numticks if presets is None: self.presets = {} else: self.presets = presets @property def numticks(self): # Old hard-coded default. return self._numticks if self._numticks is not None else 11 @numticks.setter def numticks(self, numticks): self._numticks = numticks 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) def tick_values(self, vmin, vmax): vmin, vmax = mtransforms.nonsingular(vmin, vmax, expander=0.05) if (vmin, vmax) in self.presets: return self.presets[(vmin, vmax)] if self.numticks == 0: return [] ticklocs = np.linspace(vmin, vmax, self.numticks) return self.raise_if_exceeds(ticklocs) 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 mpl.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) class MultipleLocator(Locator): """ Set a tick on each integer multiple of the *base* plus an *offset* within the view interval. """ def __init__(self, base=1.0, offset=0.0): """ Parameters ---------- base : float > 0 Interval between ticks. offset : float Value added to each multiple of *base*. .. versionadded:: 3.8 """ self._edge = _Edge_integer(base, 0) self._offset = offset def set_params(self, base=None, offset=None): """ Set parameters within this locator. Parameters ---------- base : float > 0 Interval between ticks. offset : float Value added to each multiple of *base*. .. versionadded:: 3.8 """ if base is not None: self._edge = _Edge_integer(base, 0) if offset is not None: self._offset = offset def __call__(self): """Return the locations of the ticks.""" vmin, vmax = self.axis.get_view_interval() return self.tick_values(vmin, vmax) def tick_values(self, vmin, vmax): if vmax < vmin: vmin, vmax = vmax, vmin step = self._edge.step vmin -= self._offset vmax -= self._offset vmin = self._edge.ge(vmin) * step n = (vmax - vmin + 0.001 * step) // step locs = vmin - step + np.arange(n + 3) * step + self._offset return self.raise_if_exceeds(locs) def view_limits(self, dmin, dmax): """ Set the view limits to the nearest tick values that contain the data. """ if mpl.rcParams['axes.autolimit_mode'] == 'round_numbers': vmin = self._edge.le(dmin - self._offset) * self._edge.step + self._offset vmax = self._edge.ge(dmax - self._offset) * self._edge.step + self._offset 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): """ Parameters ---------- step : float > 0 Interval between ticks. offset : float 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 class MaxNLocator(Locator): """ Find nice tick locations with no more than *nbins* + 1 being within the view limits. Locations beyond the limits are added to support autoscaling. """ default_params = dict(nbins=10, steps=None, integer=False, symmetric=False, prune=None, min_n_ticks=2) def __init__(self, nbins=None, **kwargs): """ Parameters ---------- nbins : int or 'auto', 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 acceptable tick multiples, starting with 1 and ending with 10. For example, if ``steps=[1, 2, 4, 5, 10]``, ``20, 40, 60`` or ``0.4, 0.6, 0.8`` would be possible sets of ticks because they are multiples of 2. ``30, 60, 90`` would not be generated because 3 does not appear in this example list of steps. integer : bool, 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, default: False If True, autoscaling will result in a range symmetric about zero. prune : {'lower', 'upper', 'both', None}, default: None Remove the 'lower' tick, the 'upper' tick, or ticks on 'both' sides *if they fall exactly on an axis' edge* (this typically occurs when :rc:`axes.autolimit_mode` is 'round_numbers'). Removing such ticks is mostly useful for stacked or ganged plots, where the upper tick of an axes overlaps with the lower tick of the axes above it. min_n_ticks : int, default: 2 Relax *nbins* and *integer* constraints if necessary to obtain this minimum number of ticks. """ if nbins is not None: kwargs['nbins'] = 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.concatenate([[1], steps]) if steps[-1] != 10: steps = np.concatenate([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. return np.concatenate([0.1 * steps[:-1], steps, [10 * steps[1]]]) 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') _api.check_in_list(['upper', 'lower', 'both', None], prune=prune) 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: raise _api.kwarg_error("set_params", kwargs) 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 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] raw_step = ((_vmax - _vmin) / nbins) large_steps = steps >= raw_step if mpl.rcParams['axes.autolimit_mode'] == 'round_numbers': # Classic round_numbers mode may require a larger step. # Get first multiple of steps that are <= _vmin floored_vmins = (_vmin // steps) * steps floored_vmaxs = floored_vmins + steps * nbins large_steps = large_steps & (floored_vmaxs >= _vmax) # Find index of smallest large step istep = np.nonzero(large_steps)[0][0] # Start at smallest of the steps greater than the raw step, and check # if it provides enough ticks. If not, work backwards through # smaller steps until one is found that provides enough ticks. for step in steps[:istep+1][::-1]: 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) 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) 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 mpl.rcParams['axes.autolimit_mode'] == 'round_numbers': return self._raw_ticks(dmin, dmax)[[0, -1]] else: return dmin, dmax def _is_decade(x, *, base=10, rtol=None): """Return True if *x* is an integer power of *base*.""" if not np.isfinite(x): return False if x == 0.0: return True lx = np.log(abs(x)) / np.log(base) if rtol is None: return np.isclose(lx, np.round(lx)) else: return np.isclose(lx, np.round(lx), rtol=rtol) 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 math.isclose(x, round(x)) class LogLocator(Locator): """ Determine the tick locations for log axes. Place ticks on the locations : ``subs[j] * base**i`` Parameters ---------- base : float, default: 10.0 The base of the log used, so major ticks are placed at ``base**n``, where ``n`` is an integer. subs : None or {'auto', 'all'} or sequence of float, default: (1.0,) Gives the multiples of integer powers of the base at which to place ticks. The default of ``(1.0, )`` places ticks only at integer powers of the base. Permitted string values are ``'auto'`` and ``'all'``. Both of these 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'``. numticks : None or int, default: None The maximum number of ticks to allow on a given axis. The default of ``None`` will try to choose intelligently as long as this Locator has already been assigned to an axis using `~.axis.Axis.get_tick_space`, but otherwise falls back to 9. """ @_api.delete_parameter("3.8", "numdecs") def __init__(self, base=10.0, subs=(1.0,), numdecs=4, numticks=None): """Place ticks on the locations : subs[j] * base**i.""" if numticks is None: if mpl.rcParams['_internal.classic_mode']: numticks = 15 else: numticks = 'auto' self._base = float(base) self._set_subs(subs) self._numdecs = numdecs self.numticks = numticks @_api.delete_parameter("3.8", "numdecs") def set_params(self, base=None, subs=None, numdecs=None, numticks=None): """Set parameters within this locator.""" if base is not None: self._base = float(base) if subs is not None: self._set_subs(subs) if numdecs is not None: self._numdecs = numdecs if numticks is not None: self.numticks = numticks numdecs = _api.deprecate_privatize_attribute( "3.8", addendum="This attribute has no effect.") def _set_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): _api.check_in_list(('all', 'auto'), subs=subs) self._subs = subs else: try: self._subs = np.asarray(subs, dtype=float) except ValueError as e: raise ValueError("subs must be None, 'all', 'auto' or " "a sequence of floats, not " f"{subs}.") from e if self._subs.ndim != 1: raise ValueError("A sequence passed to subs must be " "1-dimensional, not " f"{self._subs.ndim}-dimensional.") def __call__(self): """Return the locations of the ticks.""" vmin, vmax = self.axis.get_view_interval() return self.tick_values(vmin, vmax) 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 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 cannot 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): 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: _first = 2.0 if self._subs == 'auto' else 1.0 subs = np.arange(_first, b) else: subs = self._subs # Get decades between major ticks. stride = (max(math.ceil(numdec / (numticks - 1)), 1) if mpl.rcParams['_internal.classic_mode'] else numdec // numticks + 1) # if we have decided that the stride is as big or bigger than # the range, clip the stride back to the available range - 1 # with a floor of 1. This prevents getting axis with only 1 tick # visible. if stride >= numdec: stride = max(1, numdec - 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 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) def view_limits(self, vmin, vmax): """Try to choose the view limits intelligently.""" b = self._base vmin, vmax = self.nonsingular(vmin, vmax) if mpl.rcParams['axes.autolimit_mode'] == 'round_numbers': vmin = _decade_less_equal(vmin, b) vmax = _decade_greater_equal(vmax, b) return vmin, vmax def nonsingular(self, vmin, vmax): if vmin > vmax: vmin, vmax = vmax, vmin if not np.isfinite(vmin) or not np.isfinite(vmax): vmin, vmax = 1, 10 # Initial range, no data plotted yet. elif vmax <= 0: _api.warn_external( "Data has no positive values, and therefore cannot be " "log-scaled.") vmin, vmax = 1, 10 else: # Consider shared axises minpos = min(axis.get_minpos() for axis in self.axis._get_shared_axis()) 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 class SymmetricalLogLocator(Locator): """ Determine the tick locations for symmetric log axes. """ def __init__(self, transform=None, subs=None, linthresh=None, base=None): """ Parameters ---------- transform : `~.scale.SymmetricalLogTransform`, optional If set, defines the *base* and *linthresh* of the symlog transform. base, linthresh : float, optional The *base* and *linthresh* of the symlog transform, as documented for `.SymmetricalLogScale`. These parameters are only used if *transform* is not set. subs : sequence of float, default: [1] The multiples of integer powers of the base where ticks are placed, i.e., ticks are placed at ``[sub * base**i for i in ... for sub in subs]``. Notes ----- Either *transform*, or both *base* and *linthresh*, must be given. """ 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 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) def tick_values(self, vmin, vmax): linthresh = 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) if -linthresh <= vmin < vmax <= linthresh: # only the linear range is present return sorted({vmin, 0, vmax}) # Lower log range is present has_a = (vmin < -linthresh) # Upper log range is present has_c = (vmax > linthresh) # Check if linear range is present has_b = (has_a and vmax > -linthresh) or (has_c and vmin < linthresh) base = self._base def get_log_range(lo, hi): lo = np.floor(np.log(lo) / np.log(base)) hi = np.ceil(np.log(hi) / np.log(base)) return lo, hi # Calculate all the ranges, so we can determine striding a_lo, a_hi = (0, 0) if has_a: a_upper_lim = min(-linthresh, vmax) a_lo, a_hi = get_log_range(abs(a_upper_lim), abs(vmin) + 1) c_lo, c_hi = (0, 0) if has_c: c_lower_lim = max(linthresh, vmin) c_lo, c_hi = get_log_range(c_lower_lim, vmax + 1) # Calculate the total number of integer exponents in a and c ranges total_ticks = (a_hi - a_lo) + (c_hi - c_lo) if has_b: total_ticks += 1 stride = max(total_ticks // (self.numticks - 1), 1) decades = [] if has_a: decades.extend(-1 * (base ** (np.arange(a_lo, a_hi, stride)[::-1]))) if has_b: decades.append(0.0) if has_c: decades.extend(base ** (np.arange(c_lo, c_hi, stride))) 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)) def view_limits(self, vmin, vmax): """Try to choose the view limits intelligently.""" b = self._base if vmax < vmin: vmin, vmax = vmax, vmin if mpl.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) return mtransforms.nonsingular(vmin, vmax) class AsinhLocator(Locator): """ An axis tick locator specialized for the inverse-sinh scale This is very unlikely to have any use beyond the `~.scale.AsinhScale` class. .. note:: This API is provisional and may be revised in the future based on early user feedback. """ def __init__(self, linear_width, numticks=11, symthresh=0.2, base=10, subs=None): """ Parameters ---------- linear_width : float The scale parameter defining the extent of the quasi-linear region. numticks : int, default: 11 The approximate number of major ticks that will fit along the entire axis symthresh : float, default: 0.2 The fractional threshold beneath which data which covers a range that is approximately symmetric about zero will have ticks that are exactly symmetric. base : int, default: 10 The number base used for rounding tick locations on a logarithmic scale. If this is less than one, then rounding is to the nearest integer multiple of powers of ten. subs : tuple, default: None Multiples of the number base, typically used for the minor ticks, e.g. (2, 5) when base=10. """ super().__init__() self.linear_width = linear_width self.numticks = numticks self.symthresh = symthresh self.base = base self.subs = subs def set_params(self, numticks=None, symthresh=None, base=None, subs=None): """Set parameters within this locator.""" if numticks is not None: self.numticks = numticks if symthresh is not None: self.symthresh = symthresh if base is not None: self.base = base if subs is not None: self.subs = subs if len(subs) > 0 else None def __call__(self): vmin, vmax = self.axis.get_view_interval() if (vmin * vmax) < 0 and abs(1 + vmax / vmin) < self.symthresh: # Data-range appears to be almost symmetric, so round up: bound = max(abs(vmin), abs(vmax)) return self.tick_values(-bound, bound) else: return self.tick_values(vmin, vmax) def tick_values(self, vmin, vmax): # Construct a set of "on-screen" locations # that are uniformly spaced: ymin, ymax = self.linear_width * np.arcsinh(np.array([vmin, vmax]) / self.linear_width) ys = np.linspace(ymin, ymax, self.numticks) zero_dev = np.abs(ys / (ymax - ymin)) if (ymin * ymax) < 0: # Ensure that the zero tick-mark is included, # if the axis straddles zero ys = np.hstack([ys[(zero_dev > 0.5 / self.numticks)], 0.0]) # Transform the "on-screen" grid to the data space: xs = self.linear_width * np.sinh(ys / self.linear_width) zero_xs = (ys == 0) # Round the data-space values to be intuitive base-n numbers, # keeping track of positive and negative values separately, # but giving careful treatment to the zero value: if self.base > 1: log_base = math.log(self.base) powers = ( np.where(zero_xs, 0, np.sign(xs)) * np.power(self.base, np.where(zero_xs, 0.0, np.floor(np.log(np.abs(xs) + zero_xs*1e-6) / log_base))) ) if self.subs: qs = np.outer(powers, self.subs).flatten() else: qs = powers else: powers = ( np.where(xs >= 0, 1, -1) * np.power(10, np.where(zero_xs, 0.0, np.floor(np.log10(np.abs(xs) + zero_xs*1e-6)))) ) qs = powers * np.round(xs / powers) ticks = np.array(sorted(set(qs))) if len(ticks) >= 2: return ticks else: return np.linspace(vmin, vmax, self.numticks) class LogitLocator(MaxNLocator): """ Determine the tick locations for logit axes """ def __init__(self, minor=False, *, nbins="auto"): """ Place ticks on the logit locations Parameters ---------- nbins : int or 'auto', optional Number of ticks. Only used if minor is False. minor : bool, default: False Indicate if this locator is for minor ticks or not. """ self._minor = minor super().__init__(nbins=nbins, steps=[1, 2, 5, 10]) def set_params(self, minor=None, **kwargs): """Set parameters within this locator.""" if minor is not None: self._minor = minor super().set_params(**kwargs) @property def minor(self): return self._minor @minor.setter def minor(self, value): self.set_params(minor=value) 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") if self._nbins == "auto": if self.axis is not None: nbins = self.axis.get_tick_space() if nbins < 2: nbins = 2 else: nbins = 9 else: nbins = self._nbins # We define ideal ticks with their index: # linscale: ... 1e-3 1e-2 1e-1 1/2 1-1e-1 1-1e-2 1-1e-3 ... # b-scale : ... -3 -2 -1 0 1 2 3 ... def ideal_ticks(x): return 10 ** x if x < 0 else 1 - (10 ** (-x)) if x > 0 else 0.5 vmin, vmax = self.nonsingular(vmin, vmax) binf = int( np.floor(np.log10(vmin)) if vmin < 0.5 else 0 if vmin < 0.9 else -np.ceil(np.log10(1 - vmin)) ) bsup = int( np.ceil(np.log10(vmax)) if vmax <= 0.5 else 1 if vmax <= 0.9 else -np.floor(np.log10(1 - vmax)) ) numideal = bsup - binf - 1 if numideal >= 2: # have 2 or more wanted ideal ticks, so use them as major ticks if numideal > nbins: # to many ideal ticks, subsampling ideals for major ticks, and # take others for minor ticks subsampling_factor = math.ceil(numideal / nbins) if self._minor: ticklocs = [ ideal_ticks(b) for b in range(binf, bsup + 1) if (b % subsampling_factor) != 0 ] else: ticklocs = [ ideal_ticks(b) for b in range(binf, bsup + 1) if (b % subsampling_factor) == 0 ] return self.raise_if_exceeds(np.array(ticklocs)) if self._minor: ticklocs = [] for b in range(binf, bsup): if b < -1: ticklocs.extend(np.arange(2, 10) * 10 ** b) elif b == -1: ticklocs.extend(np.arange(2, 5) / 10) elif b == 0: ticklocs.extend(np.arange(6, 9) / 10) else: ticklocs.extend( 1 - np.arange(2, 10)[::-1] * 10 ** (-b - 1) ) return self.raise_if_exceeds(np.array(ticklocs)) ticklocs = [ideal_ticks(b) for b in range(binf, bsup + 1)] return self.raise_if_exceeds(np.array(ticklocs)) # the scale is zoomed so same ticks as linear scale can be used if self._minor: return [] return super().tick_values(vmin, vmax) def nonsingular(self, vmin, vmax): standard_minpos = 1e-7 initial_range = (standard_minpos, 1 - standard_minpos) if vmin > vmax: vmin, vmax = vmax, vmin if not np.isfinite(vmin) or not np.isfinite(vmax): vmin, vmax = initial_range # Initial range, no data plotted yet. elif vmax <= 0 or vmin >= 1: # vmax <= 0 occurs when all values are negative # vmin >= 1 occurs when all values are greater than one _api.warn_external( "Data has no values between 0 and 1, and therefore cannot be " "logit-scaled." ) vmin, vmax = initial_range else: minpos = ( self.axis.get_minpos() if self.axis is not None else standard_minpos ) if not np.isfinite(minpos): minpos = standard_minpos # This should never take effect. if vmin <= 0: vmin = minpos # 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 vmax >= 1: vmax = 1 - minpos if vmin == vmax: vmin, vmax = 0.1 * vmin, 1 - 0.1 * vmin return vmin, vmax 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 mpl.rcParams['_internal.classic_mode']: nbins = 9 steps = [1, 2, 5, 10] else: nbins = 'auto' steps = [1, 2, 2.5, 5, 10] super().__init__(nbins=nbins, steps=steps) 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, the value stored in rcParams will be used. In case *n* is set to 'auto', it will be set to 4 or 5. If the distance between the major ticks equals 1, 2.5, 5 or 10 it can be perfectly divided in 5 equidistant sub-intervals with a length multiple of 0.05. Otherwise it is divided in 4 sub-intervals. """ self.ndivs = n def __call__(self): """Return the locations of the ticks.""" if self.axis.get_scale() == 'log': _api.warn_external('AutoMinorLocator does not work with ' 'logarithmic scale') return [] majorlocs = np.unique(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: if self.axis.axis_name == 'y': self.ndivs = mpl.rcParams['ytick.minor.ndivs'] else: # for x and z axis self.ndivs = mpl.rcParams['xtick.minor.ndivs'] if self.ndivs == 'auto': 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 = round((vmin - t0) / minorstep) tmax = round((vmax - t0) / minorstep) + 1 locs = (np.arange(tmin, tmax) * minorstep) + t0 return self.raise_if_exceeds(locs) def tick_values(self, vmin, vmax): raise NotImplementedError('Cannot get tick locations for a ' '%s type.' % type(self))