From 5178df8d74bcdde310f8007ac891dd8a1bf4a9d2 Mon Sep 17 00:00:00 2001 From: Jonathan Jouty Date: Sun, 22 Jul 2018 02:50:17 +0200 Subject: Fix incorrect integrals in PieceWiseConstFunc (#36) * Add (some currently failing) tests for PieceWiseConstFunc.integral * Fix implementation of PieceWiseConstFunc.integral Just by adding a special condition for when we are only taking an integral "between" two edges of a PieceWiseConstFunc All tests now pass. Fixes #33. * Add PieceWiseConstFunc.integral tests for ValueError * Add testing bounds of integral * Raise ValueError in function implementation --- pyspike/PieceWiseConstFunc.py | 32 ++++++++++++++++++--------- test/test_function.py | 50 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 72 insertions(+), 10 deletions(-) diff --git a/pyspike/PieceWiseConstFunc.py b/pyspike/PieceWiseConstFunc.py index 5ce5f27..17fdd3f 100644 --- a/pyspike/PieceWiseConstFunc.py +++ b/pyspike/PieceWiseConstFunc.py @@ -129,19 +129,31 @@ class PieceWiseConstFunc(object): # no interval given, integrate over the whole spike train a = np.sum((self.x[1:]-self.x[:-1]) * self.y) else: + if interval[0]>interval[1]: + raise ValueError("Invalid averaging interval: interval[0]>=interval[1]") + if interval[0]self.x[-1]: + raise ValueError("Invalid averaging interval: interval[0] 0 and end_ind < len(self.x), \ - "Invalid averaging interval" - # first the contribution from between the indices - a = np.sum((self.x[start_ind+1:end_ind+1] - - self.x[start_ind:end_ind]) * - self.y[start_ind:end_ind]) - # correction from start to first index - a += (self.x[start_ind]-interval[0]) * self.y[start_ind-1] - # correction from last index to end - a += (interval[1]-self.x[end_ind]) * self.y[end_ind] + if start_ind > end_ind: + # contribution from between two closest edges + a = (self.x[start_ind]-self.x[end_ind]) * self.y[end_ind] + # minus the part that is not within the interval + a -= ((interval[0]-self.x[end_ind])+(self.x[start_ind]-interval[1])) * self.y[end_ind] + else: + assert start_ind > 0 and end_ind < len(self.x), \ + "Invalid averaging interval" + # first the contribution from between the indices + a = np.sum((self.x[start_ind+1:end_ind+1] - + self.x[start_ind:end_ind]) * + self.y[start_ind:end_ind]) + # correction from start to first index + a += (self.x[start_ind]-interval[0]) * self.y[start_ind-1] + # correction from last index to end + a += (interval[1]-self.x[end_ind]) * self.y[end_ind] return a def avrg(self, interval=None): diff --git a/test/test_function.py b/test/test_function.py index 92d378d..ddeb4b1 100644 --- a/test/test_function.py +++ b/test/test_function.py @@ -10,6 +10,7 @@ Distributed under the BSD License from __future__ import print_function import numpy as np from copy import copy +from nose.tools import raises from numpy.testing import assert_equal, assert_almost_equal, \ assert_array_equal, assert_array_almost_equal @@ -49,6 +50,8 @@ def test_pwc(): assert_almost_equal(a, (0.5-0.5+0.5*1.5+1.0*0.75)/3.0, decimal=16) a = f.avrg([1.5, 3.5]) assert_almost_equal(a, (-0.5*0.5+0.5*1.5+1.0*0.75)/2.0, decimal=16) + a = f.avrg([1.0, 2.0]) + assert_almost_equal(a, (1.0*-0.5)/1.0, decimal=16) a = f.avrg([1.0, 3.5]) assert_almost_equal(a, (-0.5*1.0+0.5*1.5+1.0*0.75)/2.5, decimal=16) a = f.avrg([1.0, 4.0]) @@ -120,6 +123,53 @@ def test_pwc_avrg(): assert_array_almost_equal(f1.x, x_expected, decimal=16) assert_array_almost_equal(f1.y, y_expected, decimal=16) +def test_pwc_integral(): + # some random data + x = [0.0, 1.0, 2.0, 2.5, 4.0] + y = [1.0, -0.5, 1.5, 0.75] + f1 = spk.PieceWiseConstFunc(x, y) + + # test full interval + full = 1.0*1.0 + 1.0*-0.5 + 0.5*1.5 + 1.5*0.75; + assert_equal(f1.integral(), full) + assert_equal(f1.integral((np.min(x),np.max(x))), full) + # test part interval, spanning an edge + assert_equal(f1.integral((0.5,1.5)), 0.5*1.0 + 0.5*-0.5) + # test part interval, just over two edges + assert_almost_equal(f1.integral((1.0-1e-16,2+1e-16)), 1.0*-0.5, decimal=16) + # test part interval, between two edges + assert_equal(f1.integral((1.0,2.0)), 1.0*-0.5) + assert_equal(f1.integral((1.2,1.7)), (1.7-1.2)*-0.5) + # test part interval, start to before and after edge + assert_equal(f1.integral((0.0,0.7)), 0.7*1.0) + assert_equal(f1.integral((0.0,1.1)), 1.0*1.0+0.1*-0.5) + # test part interval, before and after edge till end + assert_equal(f1.integral((2.6,4.0)), (4.0-2.6)*0.75) + assert_equal(f1.integral((2.4,4.0)), (2.5-2.4)*1.5+(4-2.5)*0.75) + +@raises(ValueError) +def test_pwc_integral_bad_bounds_inv(): + # some random data + x = [0.0, 1.0, 2.0, 2.5, 4.0] + y = [1.0, -0.5, 1.5, 0.75] + f1 = spk.PieceWiseConstFunc(x, y) + f1.integral((3,2)) + +@raises(ValueError) +def test_pwc_integral_bad_bounds_oob_1(): + # some random data + x = [0.0, 1.0, 2.0, 2.5, 4.0] + y = [1.0, -0.5, 1.5, 0.75] + f1 = spk.PieceWiseConstFunc(x, y) + f1.integral((1,6)) + +@raises(ValueError) +def test_pwc_integral_bad_bounds_oob_2(): + # some random data + x = [0.0, 1.0, 2.0, 2.5, 4.0] + y = [1.0, -0.5, 1.5, 0.75] + f1 = spk.PieceWiseConstFunc(x, y) + f1.integral((-1,3)) def test_pwl(): x = [0.0, 1.0, 2.0, 2.5, 4.0] -- cgit v1.2.3