279 lines
9.6 KiB
Python
279 lines
9.6 KiB
Python
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import numpy as np
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from matplotlib.contour import ContourSet
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from matplotlib.tri.triangulation import Triangulation
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class TriContourSet(ContourSet):
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"""
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Create and store a set of contour lines or filled regions for
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a triangular grid.
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User-callable method: clabel
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Useful attributes:
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ax:
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the axes object in which the contours are drawn
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collections:
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a silent_list of LineCollections or PolyCollections
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levels:
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contour levels
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layers:
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same as levels for line contours; half-way between
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levels for filled contours. See _process_colors method.
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"""
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def __init__(self, ax, *args, **kwargs):
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"""
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Draw triangular grid contour lines or filled regions,
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depending on whether keyword arg 'filled' is False
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(default) or True.
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The first argument of the initializer must be an axes
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object. The remaining arguments and keyword arguments
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are described in the docstring of `tricontour`.
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"""
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ContourSet.__init__(self, ax, *args, **kwargs)
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def _process_args(self, *args, **kwargs):
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"""
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Process args and kwargs.
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"""
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if isinstance(args[0], TriContourSet):
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C = args[0].cppContourGenerator
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if self.levels is None:
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self.levels = args[0].levels
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else:
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from matplotlib import _tri
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tri, z = self._contour_args(args, kwargs)
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C = _tri.TriContourGenerator(tri.get_cpp_triangulation(), z)
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self._mins = [tri.x.min(), tri.y.min()]
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self._maxs = [tri.x.max(), tri.y.max()]
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self.cppContourGenerator = C
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return kwargs
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def _get_allsegs_and_allkinds(self):
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"""
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Create and return allsegs and allkinds by calling underlying C code.
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"""
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allsegs = []
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if self.filled:
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lowers, uppers = self._get_lowers_and_uppers()
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allkinds = []
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for lower, upper in zip(lowers, uppers):
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segs, kinds = self.cppContourGenerator.create_filled_contour(
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lower, upper)
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allsegs.append([segs])
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allkinds.append([kinds])
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else:
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allkinds = None
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for level in self.levels:
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segs = self.cppContourGenerator.create_contour(level)
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allsegs.append(segs)
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return allsegs, allkinds
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def _contour_args(self, args, kwargs):
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if self.filled:
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fn = 'contourf'
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else:
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fn = 'contour'
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tri, args, kwargs = Triangulation.get_from_args_and_kwargs(*args,
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**kwargs)
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z = np.ma.asarray(args[0])
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if z.shape != tri.x.shape:
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raise ValueError('z array must have same length as triangulation x'
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' and y arrays')
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# z values must be finite, only need to check points that are included
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# in the triangulation.
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z_check = z[np.unique(tri.get_masked_triangles())]
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if np.ma.is_masked(z_check):
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raise ValueError('z must not contain masked points within the '
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'triangulation')
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if not np.isfinite(z_check).all():
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raise ValueError('z array must not contain non-finite values '
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'within the triangulation')
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z = np.ma.masked_invalid(z, copy=False)
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self.zmax = float(z_check.max())
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self.zmin = float(z_check.min())
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if self.logscale and self.zmin <= 0:
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raise ValueError('Cannot %s log of negative values.' % fn)
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self._contour_level_args(z, args[1:])
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return (tri, z)
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def tricontour(ax, *args, **kwargs):
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"""
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Draw contours on an unstructured triangular grid.
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`.tricontour` and `.tricontourf` draw contour lines and filled contours,
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respectively. Except as noted, function signatures and return values are
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the same for both versions.
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The triangulation can be specified in one of two ways; either ::
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tricontour(triangulation, ...)
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where *triangulation* is a `matplotlib.tri.Triangulation` object, or ::
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tricontour(x, y, ...)
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tricontour(x, y, triangles, ...)
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tricontour(x, y, triangles=triangles, ...)
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tricontour(x, y, mask=mask, ...)
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tricontour(x, y, triangles, mask=mask, ...)
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in which case a `.Triangulation` object will be created. See that class'
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docstring for an explanation of these cases.
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The remaining arguments may be::
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tricontour(..., Z)
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where *Z* is the array of values to contour, one per point in the
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triangulation. The level values are chosen automatically.
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::
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tricontour(..., Z, N)
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contour up to *N+1* automatically chosen contour levels (*N* intervals).
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::
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tricontour(..., Z, V)
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draw contour lines at the values specified in sequence *V*,
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which must be in increasing order.
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::
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tricontourf(..., Z, V)
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fill the (len(*V*)-1) regions between the values in *V*,
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which must be in increasing order.
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::
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tricontour(Z, **kwargs)
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Use keyword args to control colors, linewidth, origin, cmap ... see
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below for more details.
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`.tricontour(...)` returns a `~matplotlib.contour.TriContourSet` object.
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Optional keyword arguments:
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*colors*: [ *None* | string | (mpl_colors) ]
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If *None*, the colormap specified by cmap will be used.
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If a string, like 'r' or 'red', all levels will be plotted in this
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color.
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If a tuple of matplotlib color args (string, float, rgb, etc),
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different levels will be plotted in different colors in the order
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specified.
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*alpha*: float
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The alpha blending value
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*cmap*: [ *None* | Colormap ]
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A cm :class:`~matplotlib.colors.Colormap` instance or
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*None*. If *cmap* is *None* and *colors* is *None*, a
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default Colormap is used.
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*norm*: [ *None* | Normalize ]
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A :class:`matplotlib.colors.Normalize` instance for
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scaling data values to colors. If *norm* is *None* and
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*colors* is *None*, the default linear scaling is used.
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*levels* [level0, level1, ..., leveln]
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A list of floating point numbers indicating the level
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curves to draw, in increasing order; e.g., to draw just
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the zero contour pass ``levels=[0]``
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*origin*: [ *None* | 'upper' | 'lower' | 'image' ]
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If *None*, the first value of *Z* will correspond to the
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lower left corner, location (0,0). If 'image', the rc
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value for ``image.origin`` will be used.
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This keyword is not active if *X* and *Y* are specified in
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the call to contour.
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*extent*: [ *None* | (x0,x1,y0,y1) ]
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If *origin* is not *None*, then *extent* is interpreted as
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in :func:`matplotlib.pyplot.imshow`: it gives the outer
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pixel boundaries. In this case, the position of Z[0,0]
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is the center of the pixel, not a corner. If *origin* is
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*None*, then (*x0*, *y0*) is the position of Z[0,0], and
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(*x1*, *y1*) is the position of Z[-1,-1].
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This keyword is not active if *X* and *Y* are specified in
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the call to contour.
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*locator*: [ *None* | ticker.Locator subclass ]
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If *locator* is None, the default
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:class:`~matplotlib.ticker.MaxNLocator` is used. The
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locator is used to determine the contour levels if they
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are not given explicitly via the *V* argument.
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*extend*: [ 'neither' | 'both' | 'min' | 'max' ]
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Unless this is 'neither', contour levels are automatically
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added to one or both ends of the range so that all data
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are included. These added ranges are then mapped to the
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special colormap values which default to the ends of the
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colormap range, but can be set via
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:meth:`matplotlib.colors.Colormap.set_under` and
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:meth:`matplotlib.colors.Colormap.set_over` methods.
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*xunits*, *yunits*: [ *None* | registered units ]
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Override axis units by specifying an instance of a
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:class:`matplotlib.units.ConversionInterface`.
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tricontour-only keyword arguments:
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*linewidths*: [ *None* | number | tuple of numbers ]
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If *linewidths* is *None*, defaults to rc:`lines.linewidth`.
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If a number, all levels will be plotted with this linewidth.
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If a tuple, different levels will be plotted with different
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linewidths in the order specified
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*linestyles*: [ *None* | 'solid' | 'dashed' | 'dashdot' | 'dotted' ]
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If *linestyles* is *None*, the 'solid' is used.
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*linestyles* can also be an iterable of the above strings
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specifying a set of linestyles to be used. If this
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iterable is shorter than the number of contour levels
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it will be repeated as necessary.
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If contour is using a monochrome colormap and the contour
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level is less than 0, then the linestyle specified
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in :rc:`contour.negative_linestyle` will be used.
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tricontourf-only keyword arguments:
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*antialiased*: bool
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enable antialiasing
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Note: `.tricontourf` fills intervals that are closed at the top; that is,
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for boundaries *z1* and *z2*, the filled region is::
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z1 < Z <= z2
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except for the lowest interval, which is closed on both sides (i.e. it
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includes the lowest value).
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"""
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kwargs['filled'] = False
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return TriContourSet(ax, *args, **kwargs)
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def tricontourf(ax, *args, **kwargs):
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kwargs['filled'] = True
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return TriContourSet(ax, *args, **kwargs)
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tricontourf.__doc__ = tricontour.__doc__
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