From 50b85d976f2f5ec7e40faec1ede047cf45b10bc1 Mon Sep 17 00:00:00 2001 From: Mario Mulansky Date: Wed, 19 Sep 2018 16:53:50 -0700 Subject: Fix incorrect integrals in PieceWiseLinFunc (#38) Integrals of piece-wise linear functions were incorrect if the requested interval lies completely between two support points. This has been fixed, and a unit test exercising this behavior was added. Fixes #38 --- pyspike/PieceWiseLinFunc.py | 42 +++++++++++++++++++++++++++++------------- 1 file changed, 29 insertions(+), 13 deletions(-) (limited to 'pyspike/PieceWiseLinFunc.py') diff --git a/pyspike/PieceWiseLinFunc.py b/pyspike/PieceWiseLinFunc.py index 8145e63..8faaec4 100644 --- a/pyspike/PieceWiseLinFunc.py +++ b/pyspike/PieceWiseLinFunc.py @@ -146,31 +146,47 @@ class PieceWiseLinFunc: if interval is None: # no interval given, integrate over the whole spike train - integral = np.sum((self.x[1:]-self.x[:-1]) * 0.5*(self.y1+self.y2)) + return np.sum((self.x[1:]-self.x[:-1]) * 0.5*(self.y1+self.y2)) + + # find the indices corresponding to the interval + start_ind = np.searchsorted(self.x, interval[0], side='right') + end_ind = np.searchsorted(self.x, interval[1], side='left')-1 + assert start_ind > 0 and end_ind < len(self.x), \ + "Invalid averaging interval" + if start_ind > end_ind: + print(start_ind, end_ind, self.x[start_ind]) + # contribution from between two closest edges + y_x0 = intermediate_value(self.x[start_ind-1], + self.x[start_ind], + self.y1[start_ind-1], + self.y2[start_ind-1], + interval[0]) + y_x1 = intermediate_value(self.x[start_ind-1], + self.x[start_ind], + self.y1[start_ind-1], + self.y2[start_ind-1], + interval[1]) + print(y_x0, y_x1, interval[1] - interval[0]) + integral = (y_x0 + y_x1) * 0.5 * (interval[1] - interval[0]) + print(integral) else: - # find the indices corresponding to the interval - start_ind = np.searchsorted(self.x, interval[0], side='right') - end_ind = np.searchsorted(self.x, interval[1], side='left')-1 - assert start_ind > 0 and end_ind < len(self.x), \ - "Invalid averaging interval" # first the contribution from between the indices integral = np.sum((self.x[start_ind+1:end_ind+1] - - self.x[start_ind:end_ind]) * - 0.5*(self.y1[start_ind:end_ind] + - self.y2[start_ind:end_ind])) + self.x[start_ind:end_ind]) * + 0.5*(self.y1[start_ind:end_ind] + + self.y2[start_ind:end_ind])) # correction from start to first index integral += (self.x[start_ind]-interval[0]) * 0.5 * \ (self.y2[start_ind-1] + - intermediate_value(self.x[start_ind-1], + intermediate_value(self.x[start_ind-1], self.x[start_ind], self.y1[start_ind-1], self.y2[start_ind-1], - interval[0] - )) + interval[0])) # correction from last index to end integral += (interval[1]-self.x[end_ind]) * 0.5 * \ (self.y1[end_ind] + - intermediate_value(self.x[end_ind], self.x[end_ind+1], + intermediate_value(self.x[end_ind], self.x[end_ind+1], self.y1[end_ind], self.y2[end_ind], interval[1] )) -- cgit v1.2.3