SignalMixin.smooth_frames: check lengths of input arrays.

Ensure that all of the input signals have the expected lengths before
trying to do anything else.

(If any of the signal lengths were wrong, this would typically have
raised a ValueError later on - though not always, since numpy will try
to be clever if one of the arguments is an array of length 1.)

Author: Benjamin Moody

wfdb/io/_signal.py

@@ -841,6 +841,12 @@ def smooth_frames(self, sigtype='physical'):
 
         n_sig = len(expanded_signal)
         sig_len = int(len(expanded_signal[0])/spf[0])
+        for ch in range(n_sig):
+            if len(expanded_signal[ch]) != sig_len * spf[ch]:
+                raise ValueError("length mismatch: signal %d has %d samples,"
+                                 " expected %dx%d"
+                                 % (ch, len(expanded_signal),
+                                    sig_len, spf[ch]))
         signal = np.zeros((sig_len, n_sig), dtype=output_dtype)
 
         for ch in range(n_sig):