Lib: functions to easily plot FT's
This commit is contained in:
parent
770c49a646
commit
373164f1b0
|
|
@ -0,0 +1,217 @@
|
|||
"""
|
||||
Functions to simplify plotting of fourier spectra
|
||||
"""
|
||||
# vim: fdm=indent ts=4
|
||||
|
||||
import matplotlib.pyplot as plt
|
||||
import matplotlib.gridspec as gridspec
|
||||
import numpy as np
|
||||
|
||||
def plot_amplitude(*args, **kwargs):
|
||||
kwargs = { 'plot_amplitude': True, **kwargs}
|
||||
return plot_spectrum(*args, **kwargs)
|
||||
|
||||
def plot_spectrum(
|
||||
spectrum, freqs,
|
||||
plot_complex=False, plot_power=False, plot_amplitude=None,
|
||||
freq_unit="Hz", freq_scaler=1,
|
||||
title='Spectrum', xlabel='Frequency', ax=None,
|
||||
ylabel=True, grid=True,
|
||||
**plot_kwargs
|
||||
):
|
||||
""" Plot a signal's spectrum on an Axis object"""
|
||||
plot_amplitude = plot_amplitude or (not plot_power and not plot_complex)
|
||||
alpha = 1
|
||||
|
||||
if ax is None:
|
||||
ax = plt.gca()
|
||||
|
||||
if title:
|
||||
ax.set_title(title)
|
||||
if xlabel:
|
||||
ax.set_xlabel(xlabel + (" ["+freq_unit+"]" if freq_unit else "" ))
|
||||
if ylabel is True:
|
||||
ylabel = ""
|
||||
if plot_amplitude or plot_complex:
|
||||
ylabel = "Amplitude"
|
||||
if plot_power:
|
||||
if ylabel:
|
||||
ylabel += "|"
|
||||
ylabel += "Power"
|
||||
if ylabel:
|
||||
ax.set_ylabel(ylabel)
|
||||
|
||||
ax.grid(grid)
|
||||
|
||||
plot_kwargs = {'marker': '.', 'linestyle': 'solid', **plot_kwargs}
|
||||
if plot_complex:
|
||||
alpha = 0.5
|
||||
ax.plot(freqs/freq_scaler, np.real(spectrum), **{**dict(label='Real', alpha=alpha, ), **plot_kwargs})
|
||||
ax.plot(freqs/freq_scaler, np.imag(spectrum), **{**dict(label='Imag', alpha=alpha, ), **plot_kwargs})
|
||||
|
||||
if plot_power:
|
||||
ax.plot(freqs/freq_scaler, np.abs(spectrum)**2, **{**dict(label='Power', alpha=alpha,), **plot_kwargs})
|
||||
|
||||
if plot_amplitude:
|
||||
ax.plot(freqs/freq_scaler, np.abs(spectrum), **{**dict(label='Abs', alpha=alpha, ), **plot_kwargs})
|
||||
|
||||
ax.legend()
|
||||
|
||||
return ax
|
||||
|
||||
def plot_phase(
|
||||
spectrum, freqs,
|
||||
ylim_epsilon=0.5, ax=None, grid=True,
|
||||
freq_unit="Hz", freq_scaler=1, xlabel='Frequency',
|
||||
ylabel="Phase",
|
||||
major_divider=2, minor_divider=12,
|
||||
**plot_kwargs
|
||||
):
|
||||
"""
|
||||
Plot the phase of spectrum
|
||||
"""
|
||||
|
||||
if ax is None:
|
||||
ax = plt.gca()
|
||||
|
||||
if ylabel:
|
||||
ax.set_ylabel("Phase")
|
||||
if xlabel:
|
||||
ax.set_xlabel(xlabel + (" ["+freq_unit+"]" if freq_unit else "" ))
|
||||
|
||||
ax.grid(grid)
|
||||
|
||||
plot_kwargs = {'marker': '.', 'linestyle': 'solid', **plot_kwargs}
|
||||
ax.plot(freqs/freq_scaler, np.angle(spectrum), **plot_kwargs)
|
||||
ax.set_ylim(-1*np.pi - ylim_epsilon, np.pi + ylim_epsilon)
|
||||
|
||||
axis_pi_ticker(ax.yaxis, major_divider=major_divider, minor_divider=minor_divider)
|
||||
|
||||
return ax
|
||||
|
||||
def axis_pi_ticker(axis, major_divider=2, minor_divider=12):
|
||||
|
||||
major_tick = Multiple(major_divider, np.pi, '\pi')
|
||||
minor_tick = Multiple(minor_divider, np.pi, '\pi')
|
||||
|
||||
axis.set_major_locator(major_tick.locator())
|
||||
axis.set_major_formatter(major_tick.formatter())
|
||||
axis.set_minor_locator(minor_tick.locator())
|
||||
|
||||
return axis
|
||||
|
||||
def plot_signal(
|
||||
signal, sample_rate = 1,
|
||||
time=None, ax=None,
|
||||
title='Signal', ylabel='Amplitude',
|
||||
time_unit="s", xlabel='Time',
|
||||
**kwargs):
|
||||
"""
|
||||
Plot the signal in the time domain
|
||||
"""
|
||||
|
||||
if ax is None:
|
||||
ax = plt.gca()
|
||||
|
||||
if time is None:
|
||||
time = np.arange(len(signal))/sample_rate
|
||||
|
||||
if title:
|
||||
ax.set_title(title)
|
||||
if xlabel:
|
||||
ax.set_xlabel(xlabel + (" ["+time_unit+"]" if time_unit else "" ))
|
||||
if ylabel:
|
||||
ax.set_ylabel(ylabel)
|
||||
|
||||
ax.plot(time, signal, **kwargs)
|
||||
|
||||
return ax
|
||||
|
||||
def combined_spectrum_figure(
|
||||
spectrum, freqs,
|
||||
fig=None, gs=None,
|
||||
spectrum_ax=None, phase_ax=None,
|
||||
spectrum_kwargs={}, phase_kwargs={},
|
||||
**shared_kwargs
|
||||
):
|
||||
"""
|
||||
Plot both the frequencies and phase in one figure.
|
||||
"""
|
||||
|
||||
ax1, ax2 = None, None
|
||||
if spectrum_ax is not None or phase_ax is not None:
|
||||
if spectrum_ax is not None:
|
||||
ax1 = spectrum_ax
|
||||
if phase_ax is not None:
|
||||
ax2 = phase_ax
|
||||
|
||||
else:
|
||||
# configure plotting layout
|
||||
if fig is None:
|
||||
fig = plt.figure()
|
||||
|
||||
if gs is None:
|
||||
gs = gridspec.GridSpec(2, 1, figure=fig, height_ratios=[3,1], hspace=0)
|
||||
|
||||
ax1 = fig.add_subplot(gs[:-1, -1])
|
||||
ax2 = fig.add_subplot(gs[-1, -1], sharex=ax1)
|
||||
|
||||
axes = np.array([ax1, ax2])
|
||||
|
||||
# plot the spectrum
|
||||
plot_spectrum(spectrum, freqs, ax=ax1, **{ **shared_kwargs, **spectrum_kwargs})
|
||||
|
||||
# plot the phase
|
||||
plot_phase(spectrum, freqs, ax=ax2, **{ **shared_kwargs, **phase_kwargs})
|
||||
|
||||
ax1.xaxis.tick_top()
|
||||
[label.set_visible(False) for label in ax1.get_xticklabels()]
|
||||
|
||||
return fig
|
||||
|
||||
def multiple_formatter(denominator=2, number=np.pi, latex='\pi'):
|
||||
"""
|
||||
From https://stackoverflow.com/a/53586826
|
||||
"""
|
||||
def gcd(a, b):
|
||||
while b:
|
||||
a, b = b, a%b
|
||||
return a
|
||||
|
||||
def _multiple_formatter(x, pos):
|
||||
den = denominator
|
||||
num = np.int(np.rint(den*x/number))
|
||||
com = gcd(num,den)
|
||||
(num,den) = (int(num/com),int(den/com))
|
||||
if den==1:
|
||||
if num==0:
|
||||
return r'$0$'
|
||||
if num==1:
|
||||
return r'$%s$'%latex
|
||||
elif num==-1:
|
||||
return r'$-%s$'%latex
|
||||
else:
|
||||
return r'$%s%s$'%(num,latex)
|
||||
else:
|
||||
if num==1:
|
||||
return r'$\frac{%s}{%s}$'%(latex,den)
|
||||
elif num==-1:
|
||||
return r'$\frac{-%s}{%s}$'%(latex,den)
|
||||
else:
|
||||
return r'$\frac{%s%s}{%s}$'%(num,latex,den)
|
||||
return _multiple_formatter
|
||||
|
||||
class Multiple:
|
||||
"""
|
||||
From https://stackoverflow.com/a/53586826
|
||||
"""
|
||||
def __init__(self, denominator=2, number=np.pi, latex='\pi'):
|
||||
self.denominator = denominator
|
||||
self.number = number
|
||||
self.latex = latex
|
||||
|
||||
def locator(self):
|
||||
return plt.MultipleLocator(self.number / self.denominator)
|
||||
|
||||
def formatter(self):
|
||||
return plt.FuncFormatter(multiple_formatter(self.denominator, self.number, self.latex))
|
||||
Loading…
Reference in New Issue