Update fourier plotting lib

fourier/mylib/plotting.py

@@ -1,11 +1,17 @@
 """
-Functions to simplify plotting
+Functions to simplify plotting of fourier spectra
 """
 import matplotlib.pyplot as plt
 import matplotlib.gridspec as gridspec
 import numpy as np
 
-def plot_spectrum( spectrum, freqs, plot_complex=False, plot_power=False, plot_amplitude=None, ax=None, freq_unit="Hz", freq_scaler=1):
+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,
+        **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
@@ -13,8 +19,8 @@ def plot_spectrum( spectrum, freqs, plot_complex=False, plot_power=False, plot_a
     if ax is None:
         ax = plt.gca()
 
-    ax.set_title("Spectrum")
+    ax.set_title(title)
-    ax.set_xlabel("f" + (" ["+freq_unit+"]" if freq_unit else "" ))
+    ax.set_xlabel(xlabel + (" ["+freq_unit+"]" if freq_unit else "" ))
     ylabel = ""
     if plot_amplitude or plot_complex:
         ylabel = "Amplitude"
@@ -26,50 +32,90 @@ def plot_spectrum( spectrum, freqs, plot_complex=False, plot_power=False, plot_a
 
     if plot_complex:
         alpha = 0.5
-        ax.plot(freqs/freq_scaler, np.real(spectrum), '.-', label='Real', alpha=alpha)
+        ax.plot(freqs/freq_scaler, np.real(spectrum), '.-', label='Real', alpha=alpha, **plot_kwargs)
-        ax.plot(freqs/freq_scaler, np.imag(spectrum), '.-', label='Imag', alpha=alpha)
+        ax.plot(freqs/freq_scaler, np.imag(spectrum), '.-', label='Imag', alpha=alpha, **plot_kwargs)
 
     if plot_power:
-        ax.plot(freqs/freq_scaler, np.abs(spectrum)**2, '.-', label='Power', alpha=alpha)
+        ax.plot(freqs/freq_scaler, np.abs(spectrum)**2, '.-', label='Power', alpha=alpha, **plot_kwargs)
 
     if plot_amplitude:
-        ax.plot(freqs/freq_scaler, np.abs(spectrum), '.-', label='Abs', alpha=alpha)
+        ax.plot(freqs/freq_scaler, np.abs(spectrum), '.-', label='Abs', alpha=alpha, **plot_kwargs)
 
     ax.legend()
 
     return ax
 
-def plot_phase( spectrum, freqs, ylim_epsilon=0.5, ax=None, freq_unit="Hz", freq_scaler=1):
+def plot_phase(
+        spectrum, freqs,
+        ylim_epsilon=0.5, ax=None, grid=True,
+        freq_unit="Hz", freq_scaler=1, xlabel='Frequency',
+        **plot_kwargs
+    ):
+    """
+    Plot the phase of spectrum
+    """
+
     if ax is None:
         ax = plt.gca()
 
     ax.set_ylabel("Phase")
-    ax.set_xlabel("f" + (" ["+freq_unit+"]" if freq_unit else "" ))
+    ax.set_xlabel(xlabel + (" ["+freq_unit+"]" if freq_unit else "" ))
+    ax.grid(grid)
 
-    ax.plot(freqs/freq_scaler, np.angle(spectrum), '.-')
+    ax.plot(freqs/freq_scaler, np.angle(spectrum), '.-', **plot_kwargs)
     ax.set_ylim(-1*np.pi - ylim_epsilon, np.pi + ylim_epsilon)
 
+    major_tick = Multiple(2, np.pi, '\pi')
+    minor_tick = Multiple(12, np.pi, '\pi')
+    ax.yaxis.set_major_locator(major_tick.locator())
+    ax.yaxis.set_major_formatter(major_tick.formatter())
+    ax.yaxis.set_minor_locator(minor_tick.locator())
+
     return ax
 
-def plot_signal( signal, sample_rate = 1, ax=None, time=None, time_unit="s", **kwargs):
+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
 
-    ax.set_title("Signal")
+    ax.set_title(title)
-    ax.set_xlabel("t" + (" ["+time_unit+"]" if time_unit else "" ))
+    ax.set_xlabel(xlabel + (" ["+time_unit+"]" if time_unit else "" ))
-    ax.set_ylabel("A(t)")
+    ax.set_ylabel(ylabel)
 
     ax.plot(time, signal, **kwargs)
 
     return ax
 
-def plot_combined_spectrum(spectrum, freqs,
+def plot_combined_spectrum(
-                           spectrum_kwargs={}, fig=None, gs=None, freq_scaler=1, freq_unit="Hz"):
+        spectrum, freqs,
-    """Plot both the frequencies and phase in one figure."""
+        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(figsize=(8, 16))
@@ -83,13 +129,59 @@ def plot_combined_spectrum(spectrum, freqs,
     axes = np.array([ax1, ax2])
 
     # plot the spectrum
-    plot_spectrum(spectrum, freqs, ax=ax1, freq_scaler=freq_scaler, freq_unit=freq_unit, **spectrum_kwargs)
+    plot_spectrum(spectrum, freqs, ax=ax1, **{ **shared_kwargs, **spectrum_kwargs})
 
     # plot the phase
-    plot_phase(spectrum, freqs, ax=ax2, freq_scaler=freq_scaler, freq_unit=freq_unit)
+    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, axes
 
+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))