Source code for sfs.plot

"""Plot sound fields etc."""
from __future__ import division
import matplotlib.pyplot as plt
from matplotlib.patches import PathPatch
from matplotlib.path import Path
from matplotlib.collections import PatchCollection
from mpl_toolkits import axes_grid1
from mpl_toolkits.mplot3d import Axes3D
import numpy as np
from . import util
from . import defs

def _register_cmap_clip(name, original_cmap, alpha):
    """Create a color map with "over" and "under" values."""
    from matplotlib.colors import LinearSegmentedColormap
    cdict =[original_cmap]
    cmap = LinearSegmentedColormap(name, cdict)
    cmap.set_over([alpha * c + 1 - alpha for c in cmap(1.0)[:3]])
    cmap.set_under([alpha * c + 1 - alpha for c in cmap(0.0)[:3]])

# The 'coolwarm' colormap is based on the paper
# "Diverging Color Maps for Scientific Visualization" by Kenneth Moreland
_register_cmap_clip('coolwarm_clip', 'coolwarm', 0.7)

def _register_cmap_transparent(name, color):
    """Create a color map from a given color to transparent."""
    from matplotlib.colors import colorConverter, LinearSegmentedColormap
    red, green, blue = colorConverter.to_rgb(color)
    cdict = {'red': ((0, red, red), (1, red, red)),
             'green': ((0, green, green), (1, green, green)),
             'blue': ((0, blue, blue), (1, blue, blue)),
             'alpha': ((0, 0, 0), (1, 1, 1))}
    cmap = LinearSegmentedColormap(name, cdict)

_register_cmap_transparent('blacktransparent', 'black')

[docs]def virtualsource_2d(xs, ns=None, type='point', ax=None): """Draw position/orientation of virtual source.""" xs = np.asarray(xs) ns = np.asarray(ns) if ax is None: ax = plt.gca() if type == 'point': vps = plt.Circle(xs, .05, edgecolor='k', facecolor='k') ax.add_artist(vps) for n in range(1, 3): vps = plt.Circle(xs, .05+n*0.05, edgecolor='k', fill=False) ax.add_artist(vps) elif type == 'plane': ns = 0.2 * ns ax.arrow(xs[0], xs[1], ns[0], ns[1], head_width=0.05, head_length=0.1, fc='k', ec='k')
[docs]def reference_2d(xref, size=0.1, ax=None): """Draw reference/normalization point.""" xref = np.asarray(xref) if ax is None: ax = plt.gca() ax.plot((xref[0]-size, xref[0]+size), (xref[1]-size, xref[1]+size), 'k-') ax.plot((xref[0]-size, xref[0]+size), (xref[1]+size, xref[1]-size), 'k-')
[docs]def secondarysource_2d(x0, n0, grid=None): """Simple plot of secondary source locations.""" x0 = np.asarray(x0) n0 = np.asarray(n0) ax = plt.gca() # plot only secondary sources inside simulated area if grid is not None: x0, n0 = _visible_secondarysources_2d(x0, n0, grid) # plot symbols for x00 in x0: ss = plt.Circle(x00[0:2], .05, edgecolor='k', facecolor='k') ax.add_artist(ss)
[docs]def loudspeaker_2d(x0, n0, a0=0.5, size=0.08, show_numbers=False, grid=None, ax=None): """Draw loudspeaker symbols at given locations and angles. Parameters ---------- x0 : (N, 3) array_like Loudspeaker positions. n0 : (N, 3) or (3,) array_like Normal vector(s) of loudspeakers. a0 : float or (N,) array_like, optional Weighting factor(s) of loudspeakers. size : float, optional Size of loudspeakers in metres. show_numbers : bool, optional If ``True``, loudspeaker numbers are shown. grid : triple of numpy.ndarray, optional If specified, only loudspeakers within the `grid` are shown. ax : Axes object, optional The loudspeakers are plotted into this :class:`~matplotlib.axes.Axes` object or -- if not specified -- into the current axes. """ x0 = util.asarray_of_rows(x0) n0 = util.asarray_of_rows(n0) a0 = util.asarray_1d(a0).reshape(-1, 1) # plot only secondary sources inside simulated area if grid is not None: x0, n0 = _visible_secondarysources_2d(x0, n0, grid) # normalized coordinates of loudspeaker symbol (see IEC 60617-9) codes, coordinates = zip(*( (Path.MOVETO, [-0.62, 0.21]), (Path.LINETO, [-0.31, 0.21]), (Path.LINETO, [0, 0.5]), (Path.LINETO, [0, -0.5]), (Path.LINETO, [-0.31, -0.21]), (Path.LINETO, [-0.62, -0.21]), (Path.CLOSEPOLY, [0, 0]), (Path.MOVETO, [-0.31, 0.21]), (Path.LINETO, [-0.31, -0.21]), )) coordinates = np.column_stack([coordinates, np.zeros(len(coordinates))]) coordinates *= size patches = [] for x00, n00 in util.broadcast_zip(x0, n0): # rotate and translate coordinates R = util.rotation_matrix([1, 0, 0], n00) transformed_coordinates = np.inner(coordinates, R) + x00 patches.append(PathPatch(Path(transformed_coordinates[:, :2], codes))) # add collection of patches to current axis p = PatchCollection(patches, edgecolor='0', facecolor=np.tile(1 - a0, 3)) if ax is None: ax = plt.gca() ax.add_collection(p) if show_numbers: for idx, (x00, n00) in enumerate(util.broadcast_zip(x0, n0)): x, y = x00[:2] - 1.2 * size * n00[:2] ax.text(x, y, idx + 1, horizontalalignment='center', verticalalignment='center')
def _visible_secondarysources_2d(x0, n0, grid): """Determine secondary sources which lie within `grid`.""" x, y = util.as_xyz_components(grid[:2]) idx = np.where((x0[:, 0] > x.min()) & (x0[:, 0] < x.max()) & (x0[:, 1] > y.min()) & (x0[:, 1] < x.max())) idx = np.squeeze(idx) return x0[idx, :], n0[idx, :]
[docs]def loudspeaker_3d(x0, n0, a0=None, w=0.08, h=0.08): """Plot positions and normals of a 3D secondary source distribution.""" fig = plt.figure(figsize=(15, 15)) ax = fig.add_subplot(111, projection='3d') ax.quiver(x0[:, 0], x0[:, 1], x0[:, 2], n0[:, 0], n0[:, 1], n0[:, 2], length=0.1) plt.xlabel('x (m)') plt.ylabel('y (m)') plt.title('Secondary Sources')
[docs]def soundfield(p, grid, xnorm=None, cmap='coolwarm_clip', vmin=-2.0, vmax=2.0, xlabel=None, ylabel=None, colorbar=True, colorbar_kwargs={}, ax=None, **kwargs): """Two-dimensional plot of sound field. Parameters ---------- p : array_like Sound pressure values (or any other scalar quantity if you like). If the values are complex, the imaginary part is ignored. Typically, `p` is two-dimensional with a shape of `(Ny, Nx)`, `(Nz, Nx)` or `(Nz, Ny)`. This is the case if :func:`sfs.util.xyz_grid` was used with a single number for `z`, `y` or `x`, respectively. However, `p` can also be three-dimensional with a shape of `(Ny, Nx, 1)`, `(1, Nx, Nz)` or `(Ny, 1, Nz)`. This is the case if :func:`numpy.meshgrid` was used with a scalar for `z`, `y` or `x`, respectively (and of course with the default ``indexing='xy'``). .. note:: If you want to plot a single slice of a pre-computed "full" 3D sound field, make sure that the slice still has three dimensions (including one singleton dimension). This way, you can use the original `grid` of the full volume without changes. This works because the grid component corresponding to the singleton dimension is simply ignored. grid : triple or pair of numpy.ndarray The grid that was used to calculate `p`, see :func:`sfs.util.xyz_grid`. If `p` is two-dimensional, but `grid` has 3 components, one of them must be scalar. xnorm : array_like, optional Coordinates of a point to which the sound field should be normalized before plotting. If not specified, no normalization is used. See :func:`sfs.util.normalize`. Returns ------- AxesImage See :func:`matplotlib.pyplot.imshow`. Other Parameters ---------------- xlabel, ylabel : str Overwrite default x/y labels. Use ``xlabel=''`` and ``ylabel=''`` to remove x/y labels. The labels can be changed afterwards with :func:`matplotlib.pyplot.xlabel` and :func:`matplotlib.pyplot.ylabel`. colorbar : bool, optional If ``False``, no colorbar is created. colorbar_kwargs : dict, optional Further colorbar arguments, see :func:`add_colorbar`. ax : Axes, optional If given, the plot is created on `ax` instead of the current axis (see :func:`matplotlib.pyplot.gca`). cmap, vmin, vmax, **kwargs All further parameters are forwarded to :func:`matplotlib.pyplot.imshow`. See Also -------- sfs.plot.level """ p = np.asarray(p) grid = util.as_xyz_components(grid) # normalize sound field wrt xnorm if xnorm is not None: p = util.normalize(p, grid, xnorm) if p.ndim == 3: if p.shape[2] == 1: p = p[:, :, 0] # first axis: y; second axis: x plotting_plane = 'xy' elif p.shape[1] == 1: p = p[:, 0, :].T # first axis: z; second axis: y plotting_plane = 'yz' elif p.shape[0] == 1: p = p[0, :, :].T # first axis: z; second axis: x plotting_plane = 'xz' else: raise ValueError("If p is 3D, one dimension must have length 1") elif len(grid) == 3: if grid[2].ndim == 0: plotting_plane = 'xy' elif grid[1].ndim == 0: plotting_plane = 'xz' elif grid[0].ndim == 0: plotting_plane = 'yz' else: raise ValueError( "If p is 2D and grid is 3D, one grid component must be scalar") else: # 2-dimensional case plotting_plane = 'xy' if plotting_plane == 'xy': x, y = grid[[0, 1]] elif plotting_plane == 'xz': x, y = grid[[0, 2]] elif plotting_plane == 'yz': x, y = grid[[1, 2]] if ax is None: ax = plt.gca() im = ax.imshow(np.real(p), cmap=cmap, origin='lower', extent=[x.min(), x.max(), y.min(), y.max()], vmax=vmax, vmin=vmin, **kwargs) if xlabel is None: xlabel = plotting_plane[0] + ' / m' if ylabel is None: ylabel = plotting_plane[1] + ' / m' ax.set_xlabel(xlabel) ax.set_ylabel(ylabel) if colorbar: add_colorbar(im, **colorbar_kwargs) return im
[docs]def level(p, grid, xnorm=None, power=False, cmap=None, vmax=3, vmin=-50, **kwargs): """Two-dimensional plot of level (dB) of sound field. Takes the same parameters as :func:`sfs.plot.soundfield`. Other Parameters ---------------- power : bool, optional See :func:`sfs.util.db`. """ # normalize before converting to dB! if xnorm is not None: p = util.normalize(p, grid, xnorm) L = util.db(p, power=power) return soundfield(L, grid=grid, xnorm=None, cmap=cmap, vmax=vmax, vmin=vmin, **kwargs)
[docs]def particles(x, trim=None, ax=None, xlabel='x (m)', ylabel='y (m)', edgecolor='', **kwargs): """Plot particle positions as scatter plot""" XX, YY = [np.real(c) for c in x[:2]] if trim is not None: xmin, xmax, ymin, ymax = trim idx = np.where((XX > xmin) & (XX < xmax) & (YY > ymin) & (YY < ymax)) XX = XX[idx] YY = YY[idx] if ax is None: ax = plt.gca() ax.scatter(XX, YY, edgecolor=edgecolor, **kwargs) if xlabel: ax.set_xlabel(xlabel) if ylabel: ax.set_ylabel(ylabel)
[docs]def vectors(v, grid, cmap='blacktransparent', headlength=3, headaxislength=2.5, ax=None, clim=None, **kwargs): """Plot a vector field in the xy plane. Parameters ---------- v : triple or pair of array_like x, y and optionally z components of vector field. The z components are ignored. If the values are complex, the imaginary parts are ignored. grid : triple or pair of array_like The grid that was used to calculate `v`, see :func:`sfs.util.xyz_grid`. Any z components are ignored. Returns ------- Quiver See :func:`matplotlib.pyplot.quiver`. Other Parameters ---------------- ax : Axes, optional If given, the plot is created on `ax` instead of the current axis (see :func:`matplotlib.pyplot.gca`). clim : pair of float, optional Limits for the scaling of arrow colors. See :func:`matplotlib.pyplot.quiver`. cmap, headlength, headaxislength, **kwargs All further parameters are forwarded to :func:`matplotlib.pyplot.quiver`. """ v = util.as_xyz_components(v[:2]).apply(np.real) X, Y = util.as_xyz_components(grid[:2]) speed = np.linalg.norm(v) with np.errstate(invalid='ignore'): U, V = v.apply(np.true_divide, speed) if ax is None: ax = plt.gca() if clim is None: v_ref = 1 / (defs.rho0 * defs.c) # reference particle velocity clim = 0, 2 * v_ref return ax.quiver(X, Y, U, V, speed, cmap=cmap, pivot='mid', units='xy', angles='xy', headlength=headlength, headaxislength=headaxislength, clim=clim, **kwargs)
[docs]def add_colorbar(im, aspect=20, pad=0.5, **kwargs): """Add a vertical color bar to a plot. Parameters ---------- im : ScalarMappable The output of :func:`sfs.plot.soundfield`, :func:`sfs.plot.level` or any other :class:``. aspect : float, optional Aspect ratio of the colorbar. Strictly speaking, since the colorbar is vertical, it's actually the inverse of the aspect ratio. pad : float, optional Space between image plot and colorbar, as a fraction of the width of the colorbar. .. note:: The `pad` argument of :meth:`matplotlib.figure.Figure.colorbar` has a slightly different meaning ("fraction of original axes")! \**kwargs All further arguments are forwarded to :meth:`matplotlib.figure.Figure.colorbar`. See Also -------- matplotlib.pyplot.colorbar """ ax = im.axes divider = axes_grid1.make_axes_locatable(ax) width = axes_grid1.axes_size.AxesY(ax, aspect=1/aspect) pad = axes_grid1.axes_size.Fraction(pad, width) current_ax = plt.gca() cax = divider.append_axes("right", size=width, pad=pad) return ax.figure.colorbar(im, cax=cax, orientation='vertical', **kwargs)