Remove matplotlib dependency

Author: endolith

waveform_analysis/_common.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 
 from numpy import array_equal, polyfit, sqrt, mean, absolute, log10, arange
+import numpy as np
 from scipy.stats import gmean
 
 try:
@@ -110,13 +111,21 @@ def analyze_channels(filename, function):
             function(channel, sample_rate)
 
 
+# Copied from matplotlib.mlab:
+
 def rms_flat(a):
     """
     Return the root mean square of all the elements of *a*, flattened out.
     """
     return sqrt(mean(absolute(a)**2))
 
 
+def find(condition):
+    "Return the indices where ravel(condition) is true"
+    res, = np.nonzero(np.ravel(condition))
+    return res
+
+
 def dB(q):
     """
     Return the level of a field quantity in decibels.

waveform_analysis/freq_estimation.py

@@ -3,7 +3,7 @@
 from waveform_analysis._common import parabolic
 from numpy.fft import rfft
 from numpy import asarray, argmax, mean, diff, log, copy
-from matplotlib.mlab import find
+from waveform_analysis._common import find
 from scipy.signal import correlate, kaiser, decimate