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Diffstat (limited to 'pyspike/cython/python_backend.py')
| -rw-r--r-- | pyspike/cython/python_backend.py | 638 |
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diff --git a/pyspike/cython/python_backend.py b/pyspike/cython/python_backend.py new file mode 100644 index 0000000..e75f181 --- /dev/null +++ b/pyspike/cython/python_backend.py @@ -0,0 +1,638 @@ +""" python_backend.py + +Collection of python functions that can be used instead of the cython +implementation. + +Copyright 2014-2015, Mario Mulansky <mario.mulansky@gmx.net> + +Distributed under the BSD License + +""" + +import numpy as np + + +############################################################ +# isi_distance_python +############################################################ +def isi_distance_python(s1, s2, t_start, t_end): + """ Plain Python implementation of the isi distance. + """ + N1 = len(s1) + N2 = len(s2) + + # compute the isi-distance + spike_events = np.empty(N1+N2+2) + spike_events[0] = t_start + # the values have one entry less - the number of intervals between events + isi_values = np.empty(len(spike_events) - 1) + if s1[0] > t_start: + # edge correction + nu1 = max(s1[0] - t_start, s1[1] - s1[0]) if N1 > 1 else s1[0]-t_start + index1 = -1 + else: + nu1 = s1[1] - s1[0] if N1 > 1 else t_end-s1[0] + index1 = 0 + if s2[0] > t_start: + # edge correction + nu2 = max(s2[0] - t_start, s2[1] - s2[0]) if N2 > 1 else s2[0]-t_start + index2 = -1 + else: + nu2 = s2[1] - s2[0] if N2 > 1 else t_end-s2[0] + index2 = 0 + + isi_values[0] = abs(nu1 - nu2) / max(nu1, nu2) + index = 1 + while index1+index2 < N1+N2-2: + # check which spike is next - from s1 or s2 + if (index1 < N1-1) and (index2 == N2-1 or s1[index1+1] < s2[index2+1]): + index1 += 1 + spike_events[index] = s1[index1] + if index1 < N1-1: + nu1 = s1[index1+1]-s1[index1] + else: + # edge correction + nu1 = max(t_end-s1[N1-1], s1[N1-1]-s1[N1-2]) if N1 > 1 \ + else t_end-s1[N1-1] + + elif (index2 < N2-1) and (index1 == N1-1 or + s1[index1+1] > s2[index2+1]): + index2 += 1 + spike_events[index] = s2[index2] + if index2 < N2-1: + nu2 = s2[index2+1]-s2[index2] + else: + # edge correction + nu2 = max(t_end-s2[N2-1], s2[N2-1]-s2[N2-2]) if N2 > 1 \ + else t_end-s2[N2-1] + + else: # s1[index1 + 1] == s2[index2 + 1] + index1 += 1 + index2 += 1 + spike_events[index] = s1[index1] + if index1 < N1-1: + nu1 = s1[index1+1]-s1[index1] + else: + # edge correction + nu1 = max(t_end-s1[N1-1], s1[N1-1]-s1[N1-2]) if N1 > 1 \ + else t_end-s1[N1-1] + if index2 < N2-1: + nu2 = s2[index2+1]-s2[index2] + else: + # edge correction + nu2 = max(t_end-s2[N2-1], s2[N2-1]-s2[N2-2]) if N2 > 1 \ + else t_end-s2[N2-1] + # compute the corresponding isi-distance + isi_values[index] = abs(nu1 - nu2) / \ + max(nu1, nu2) + index += 1 + # the last event is the interval end + if spike_events[index-1] == t_end: + index -= 1 + else: + spike_events[index] = t_end + # use only the data added above + # could be less than original length due to equal spike times + return spike_events[:index + 1], isi_values[:index] + + +############################################################ +# get_min_dist +############################################################ +def get_min_dist(spike_time, spike_train, start_index, t_start, t_end): + """ Returns the minimal distance |spike_time - spike_train[i]| + with i>=start_index. + """ + d = abs(spike_time - t_start) + if start_index < 0: + start_index = 0 + while start_index < len(spike_train): + d_temp = abs(spike_time - spike_train[start_index]) + if d_temp > d: + return d + else: + d = d_temp + start_index += 1 + # finally, check the distance to end time + d_temp = abs(t_end - spike_time) + if d_temp > d: + return d + else: + return d_temp + + +############################################################ +# spike_distance_python +############################################################ +def spike_distance_python(spikes1, spikes2, t_start, t_end): + """ Computes the instantaneous spike-distance S_spike (t) of the two given + spike trains. The spike trains are expected to have auxiliary spikes at the + beginning and end of the interval. Use the function add_auxiliary_spikes to + add those spikes to the spike train. + Args: + - spikes1, spikes2: ordered arrays of spike times with auxiliary spikes. + - t_start, t_end: edges of the spike train + Returns: + - PieceWiseLinFunc describing the spike-distance. + """ + + # shorter variables + t1 = spikes1 + t2 = spikes2 + + N1 = len(t1) + N2 = len(t2) + + spike_events = np.empty(N1+N2+2) + + y_starts = np.empty(len(spike_events)-1) + y_ends = np.empty(len(spike_events)-1) + + t_aux1 = np.zeros(2) + t_aux2 = np.zeros(2) + t_aux1[0] = min(t_start, t1[0]-(t1[1]-t1[0])) if N1 > 1 else t_start + t_aux1[1] = max(t_end, t1[N1-1]+(t1[N1-1]-t1[N1-2])) if N1 > 1 else t_end + t_aux2[0] = min(t_start, t2[0]-(t2[1]-t2[0])) if N2 > 1 else t_start + t_aux2[1] = max(t_end, t2[N2-1]+(t2[N2-1]-t2[N2-2])) if N2 > 1 else t_end + t_p1 = t_start if (t1[0] == t_start) else t_aux1[0] + t_p2 = t_start if (t2[0] == t_start) else t_aux2[0] + + # print "t_aux1", t_aux1, ", t_aux2:", t_aux2 + + spike_events[0] = t_start + if t1[0] > t_start: + t_f1 = t1[0] + dt_f1 = get_min_dist(t_f1, t2, 0, t_aux2[0], t_aux2[1]) + dt_p1 = dt_f1 + isi1 = max(t_f1-t_start, t1[1]-t1[0]) if N1 > 1 else t_f1-t_start + # s1 = dt_p1*(t_f1-t_start)/isi1 + s1 = dt_p1 + index1 = -1 + else: + # dt_p1 = t_start-t_p2 + t_f1 = t1[1] if N1 > 1 else t_end + dt_p1 = get_min_dist(t_p1, t2, 0, t_aux2[0], t_aux2[1]) + dt_f1 = get_min_dist(t_f1, t2, 0, t_aux2[0], t_aux2[1]) + isi1 = t_f1-t1[0] + s1 = dt_p1 + index1 = 0 + if t2[0] > t_start: + # dt_p1 = t2[0]-t_start + t_f2 = t2[0] + dt_f2 = get_min_dist(t_f2, t1, 0, t_aux1[0], t_aux1[1]) + dt_p2 = dt_f2 + isi2 = max(t_f2-t_start, t2[1]-t2[0]) if N2 > 1 else t_f2-t_start + # s2 = dt_p2*(t_f2-t_start)/isi2 + s2 = dt_p2 + index2 = -1 + else: + t_f2 = t2[1] if N2 > 1 else t_end + dt_p2 = get_min_dist(t_p2, t1, 0, t_aux1[0], t_aux1[1]) + dt_f2 = get_min_dist(t_f2, t1, 0, t_aux1[0], t_aux1[1]) + isi2 = t_f2-t2[0] + s2 = dt_p2 + index2 = 0 + + y_starts[0] = (s1*isi2 + s2*isi1) / (0.5*(isi1+isi2)**2) + index = 1 + + while index1+index2 < N1+N2-2: + # print(index, index1, index2) + if (index1 < N1-1) and (t_f1 < t_f2 or index2 == N2-1): + index1 += 1 + # first calculate the previous interval end value + s1 = dt_f1*(t_f1-t_p1) / isi1 + # the previous time now was the following time before: + dt_p1 = dt_f1 + t_p1 = t_f1 # t_p1 contains the current time point + # get the next time + if index1 < N1-1: + t_f1 = t1[index1+1] + else: + t_f1 = t_aux1[1] + spike_events[index] = t_p1 + s2 = (dt_p2*(t_f2-t_p1) + dt_f2*(t_p1-t_p2)) / isi2 + y_ends[index-1] = (s1*isi2 + s2*isi1) / (0.5*(isi1+isi2)**2) + # now the next interval start value + if index1 < N1-1: + dt_f1 = get_min_dist(t_f1, t2, index2, t_aux2[0], t_aux2[1]) + isi1 = t_f1-t_p1 + s1 = dt_p1 + else: + dt_f1 = dt_p1 + isi1 = max(t_end-t1[N1-1], t1[N1-1]-t1[N1-2]) if N1 > 1 \ + else t_end-t1[N1-1] + # s1 needs adjustment due to change of isi1 + # s1 = dt_p1*(t_end-t1[N1-1])/isi1 + # Eero's correction: no adjustment + s1 = dt_p1 + # s2 is the same as above, thus we can compute y2 immediately + y_starts[index] = (s1*isi2 + s2*isi1) / (0.5*(isi1+isi2)**2) + elif (index2 < N2-1) and (t_f1 > t_f2 or index1 == N1-1): + index2 += 1 + # first calculate the previous interval end value + s2 = dt_f2*(t_f2-t_p2) / isi2 + # the previous time now was the following time before: + dt_p2 = dt_f2 + t_p2 = t_f2 # t_p1 contains the current time point + # get the next time + if index2 < N2-1: + t_f2 = t2[index2+1] + else: + t_f2 = t_aux2[1] + spike_events[index] = t_p2 + s1 = (dt_p1*(t_f1-t_p2) + dt_f1*(t_p2-t_p1)) / isi1 + y_ends[index-1] = (s1*isi2 + s2*isi1) / (0.5*(isi1+isi2)**2) + # now the next interval start value + if index2 < N2-1: + dt_f2 = get_min_dist(t_f2, t1, index1, t_aux1[0], t_aux1[1]) + isi2 = t_f2-t_p2 + s2 = dt_p2 + else: + dt_f2 = dt_p2 + isi2 = max(t_end-t2[N2-1], t2[N2-1]-t2[N2-2]) if N2 > 1 \ + else t_end-t2[N2-1] + # s2 needs adjustment due to change of isi2 + # s2 = dt_p2*(t_end-t2[N2-1])/isi2 + # Eero's adjustment: no correction + s2 = dt_p2 + # s2 is the same as above, thus we can compute y2 immediately + y_starts[index] = (s1*isi2 + s2*isi1) / (0.5*(isi1+isi2)**2) + else: # t_f1 == t_f2 - generate only one event + index1 += 1 + index2 += 1 + t_p1 = t_f1 + t_p2 = t_f2 + dt_p1 = 0.0 + dt_p2 = 0.0 + spike_events[index] = t_f1 + y_ends[index-1] = 0.0 + y_starts[index] = 0.0 + if index1 < N1-1: + t_f1 = t1[index1+1] + dt_f1 = get_min_dist(t_f1, t2, index2, t_aux2[0], t_aux2[1]) + isi1 = t_f1 - t_p1 + else: + t_f1 = t_aux1[1] + dt_f1 = dt_p1 + isi1 = max(t_end-t1[N1-1], t1[N1-1]-t1[N1-2]) if N1 > 1 \ + else t_end-t1[N1-1] + if index2 < N2-1: + t_f2 = t2[index2+1] + dt_f2 = get_min_dist(t_f2, t1, index1, t_aux1[0], t_aux1[1]) + isi2 = t_f2 - t_p2 + else: + t_f2 = t_aux2[1] + dt_f2 = dt_p2 + isi2 = max(t_end-t2[N2-1], t2[N2-1]-t2[N2-2]) if N2 > 1 \ + else t_end-t2[N2-1] + index += 1 + + # the last event is the interval end + if spike_events[index-1] == t_end: + index -= 1 + else: + spike_events[index] = t_end + s1 = dt_f1 # *(t_end-t1[N1-1])/isi1 + s2 = dt_f2 # *(t_end-t2[N2-1])/isi2 + y_ends[index-1] = (s1*isi2 + s2*isi1) / (0.5*(isi1+isi2)**2) + + # use only the data added above + # could be less than original length due to equal spike times + return spike_events[:index+1], y_starts[:index], y_ends[:index] + + +############################################################ +# cumulative_sync_python +############################################################ +def cumulative_sync_python(spikes1, spikes2): + + def get_tau(spikes1, spikes2, i, j): + return 0.5*min([spikes1[i]-spikes1[i-1], spikes1[i+1]-spikes1[i], + spikes2[j]-spikes2[j-1], spikes2[j+1]-spikes2[j]]) + N1 = len(spikes1) + N2 = len(spikes2) + i = 0 + j = 0 + n = 0 + st = np.zeros(N1 + N2 - 2) + c = np.zeros(N1 + N2 - 3) + c[0] = 0 + st[0] = 0 + while n < N1 + N2: + if spikes1[i+1] < spikes2[j+1]: + i += 1 + n += 1 + tau = get_tau(spikes1, spikes2, i, j) + st[n] = spikes1[i] + if spikes1[i]-spikes2[j] > tau: + c[n] = c[n-1] + else: + c[n] = c[n-1]+1 + elif spikes1[i+1] > spikes2[j+1]: + j += 1 + n += 1 + tau = get_tau(spikes1, spikes2, i, j) + st[n] = spikes2[j] + if spikes2[j]-spikes1[i] > tau: + c[n] = c[n-1] + else: + c[n] = c[n-1]+1 + else: # spikes1[i+1] = spikes2[j+1] + j += 1 + i += 1 + if i == N1-1 or j == N2-1: + break + n += 1 + st[n] = spikes1[i] + c[n] = c[n-1] + n += 1 + st[n] = spikes1[i] + c[n] = c[n-1]+1 + c[0] = 0 + st[0] = spikes1[0] + st[-1] = spikes1[-1] + + return st, c + + +def get_tau(spikes1, spikes2, i, j, max_tau, init_tau): + m = init_tau + if i < len(spikes1)-1 and i > -1: + m = min(m, spikes1[i+1]-spikes1[i]) + if j < len(spikes2)-1 and j > -1: + m = min(m, spikes2[j+1]-spikes2[j]) + if i > 0: + m = min(m, spikes1[i]-spikes1[i-1]) + if j > 0: + m = min(m, spikes2[j]-spikes2[j-1]) + m *= 0.5 + if max_tau > 0.0: + m = min(m, max_tau) + return m + + +############################################################ +# coincidence_python +############################################################ +def coincidence_python(spikes1, spikes2, t_start, t_end, max_tau): + + N1 = len(spikes1) + N2 = len(spikes2) + i = -1 + j = -1 + n = 0 + st = np.zeros(N1 + N2 + 2) # spike times + c = np.zeros(N1 + N2 + 2) # coincidences + mp = np.ones(N1 + N2 + 2) # multiplicity + while i + j < N1 + N2 - 2: + if (i < N1-1) and (j == N2-1 or spikes1[i+1] < spikes2[j+1]): + i += 1 + n += 1 + tau = get_tau(spikes1, spikes2, i, j, max_tau, t_end-t_start) + st[n] = spikes1[i] + if j > -1 and spikes1[i]-spikes2[j] < tau: + # coincidence between the current spike and the previous spike + # both get marked with 1 + c[n] = 1 + c[n-1] = 1 + elif (j < N2-1) and (i == N1-1 or spikes1[i+1] > spikes2[j+1]): + j += 1 + n += 1 + tau = get_tau(spikes1, spikes2, i, j, max_tau, t_end-t_start) + st[n] = spikes2[j] + if i > -1 and spikes2[j]-spikes1[i] < tau: + # coincidence between the current spike and the previous spike + # both get marked with 1 + c[n] = 1 + c[n-1] = 1 + else: # spikes1[i+1] = spikes2[j+1] + # advance in both spike trains + j += 1 + i += 1 + n += 1 + # add only one event, but with coincidence 2 and multiplicity 2 + st[n] = spikes1[i] + c[n] = 2 + mp[n] = 2 + + st = st[:n+2] + c = c[:n+2] + mp = mp[:n+2] + + st[0] = t_start + st[len(st)-1] = t_end + if N1 + N2 > 0: + c[0] = c[1] + c[len(c)-1] = c[len(c)-2] + mp[0] = mp[1] + mp[len(mp)-1] = mp[len(mp)-2] + else: + c[0] = 1 + c[1] = 1 + + return st, c, mp + + +############################################################ +# coincidence_single_profile_cython +############################################################ +def coincidence_single_python(spikes1, spikes2, t_start, t_end, max_tau): + + N1 = len(spikes1) + N2 = len(spikes2) + j = -1 + c = np.zeros(N1) # coincidences + for i in range(N1): + while j < N2-1 and spikes2[j+1] < spikes1[i]: + # move forward until spikes2[j] is the last spike before spikes1[i] + # note that if spikes2[j] is after spikes1[i] we dont do anything + j += 1 + tau = get_tau(spikes1, spikes2, i, j, max_tau, t_end-t_start) + if j > -1 and abs(spikes1[i]-spikes2[j]) < tau: + # current spike in st1 is coincident + c[i] = 1 + if j < N2-1 and (j < 0 or spikes2[j] < spikes1[i]): + # in case spikes2[j] is before spikes1[i] it has to be the first or + # the one right before (see above), hence we move one forward and + # also check the next spike + j += 1 + tau = get_tau(spikes1, spikes2, i, j, max_tau, t_end-t_start) + if abs(spikes2[j]-spikes1[i]) < tau: + # current spike in st1 is coincident + c[i] = 1 + return c + + +############################################################ +# add_piece_wise_const_python +############################################################ +def add_piece_wise_const_python(x1, y1, x2, y2): + x_new = np.empty(len(x1) + len(x2)) + y_new = np.empty(len(x_new)-1) + x_new[0] = x1[0] + y_new[0] = y1[0] + y2[0] + index1 = 0 + index2 = 0 + index = 0 + while (index1+1 < len(y1)) and (index2+1 < len(y2)): + index += 1 + # print(index1+1, x1[index1+1], y1[index1+1], x_new[index]) + if x1[index1+1] < x2[index2+1]: + index1 += 1 + x_new[index] = x1[index1] + elif x1[index1+1] > x2[index2+1]: + index2 += 1 + x_new[index] = x2[index2] + else: # x1[index1+1] == x2[index2+1]: + index1 += 1 + index2 += 1 + x_new[index] = x1[index1] + y_new[index] = y1[index1] + y2[index2] + # one array reached the end -> copy the contents of the other to the end + if index1+1 < len(y1): + x_new[index+1:index+1+len(x1)-index1-1] = x1[index1+1:] + y_new[index+1:index+1+len(y1)-index1-1] = y1[index1+1:] + y2[-1] + index += len(x1)-index1-2 + elif index2+1 < len(y2): + x_new[index+1:index+1+len(x2)-index2-1] = x2[index2+1:] + y_new[index+1:index+1+len(y2)-index2-1] = y2[index2+1:] + y1[-1] + index += len(x2)-index2-2 + else: # both arrays reached the end simultaneously + # only the last x-value missing + x_new[index+1] = x1[-1] + # the last value is again the end of the interval + # x_new[index+1] = x1[-1] + # only use the data that was actually filled + + return x_new[:index+2], y_new[:index+1] + + +############################################################ +# add_piece_lin_const_python +############################################################ +def add_piece_wise_lin_python(x1, y11, y12, x2, y21, y22): + x_new = np.empty(len(x1) + len(x2)) + y1_new = np.empty(len(x_new)-1) + y2_new = np.empty_like(y1_new) + x_new[0] = x1[0] + y1_new[0] = y11[0] + y21[0] + index1 = 0 # index for self + index2 = 0 # index for f + index = 0 # index for new + while (index1+1 < len(y11)) and (index2+1 < len(y21)): + # print(index1+1, x1[index1+1], self.y[index1+1], x_new[index]) + if x1[index1+1] < x2[index2+1]: + # first compute the end value of the previous interval + # linear interpolation of the interval + y = y21[index2] + (y22[index2]-y21[index2]) * \ + (x1[index1+1]-x2[index2]) / (x2[index2+1]-x2[index2]) + y2_new[index] = y12[index1] + y + index1 += 1 + index += 1 + x_new[index] = x1[index1] + # and the starting value for the next interval + y1_new[index] = y11[index1] + y + elif x1[index1+1] > x2[index2+1]: + # first compute the end value of the previous interval + # linear interpolation of the interval + y = y11[index1] + (y12[index1]-y11[index1]) * \ + (x2[index2+1]-x1[index1]) / \ + (x1[index1+1]-x1[index1]) + y2_new[index] = y22[index2] + y + index2 += 1 + index += 1 + x_new[index] = x2[index2] + # and the starting value for the next interval + y1_new[index] = y21[index2] + y + else: # x1[index1+1] == x2[index2+1]: + y2_new[index] = y12[index1] + y22[index2] + index1 += 1 + index2 += 1 + index += 1 + x_new[index] = x1[index1] + y1_new[index] = y11[index1] + y21[index2] + # one array reached the end -> copy the contents of the other to the end + if index1+1 < len(y11): + # compute the linear interpolations values + y = y21[index2] + (y22[index2]-y21[index2]) * \ + (x1[index1+1:-1]-x2[index2]) / (x2[index2+1]-x2[index2]) + x_new[index+1:index+1+len(x1)-index1-1] = x1[index1+1:] + y1_new[index+1:index+1+len(y11)-index1-1] = y11[index1+1:]+y + y2_new[index:index+len(y12)-index1-1] = y12[index1:-1] + y + index += len(x1)-index1-2 + elif index2+1 < len(y21): + # compute the linear interpolations values + y = y11[index1] + (y12[index1]-y11[index1]) * \ + (x2[index2+1:-1]-x1[index1]) / \ + (x1[index1+1]-x1[index1]) + x_new[index+1:index+1+len(x2)-index2-1] = x2[index2+1:] + y1_new[index+1:index+1+len(y21)-index2-1] = y21[index2+1:] + y + y2_new[index:index+len(y22)-index2-1] = y22[index2:-1] + y + index += len(x2)-index2-2 + else: # both arrays reached the end simultaneously + # only the last x-value missing + x_new[index+1] = x1[-1] + # finally, the end value for the last interval + y2_new[index] = y12[-1]+y22[-1] + # only use the data that was actually filled + return x_new[:index+2], y1_new[:index+1], y2_new[:index+1] + + +############################################################ +# add_discrete_function_python +############################################################ +def add_discrete_function_python(x1, y1, mp1, x2, y2, mp2): + + x_new = np.empty(len(x1) + len(x2)) + y_new = np.empty_like(x_new) + mp_new = np.empty_like(x_new) + x_new[0] = x1[0] + index1 = 0 + index2 = 0 + index = 0 + N1 = len(x1)-1 + N2 = len(x2)-1 + while (index1+1 < N1) and (index2+1 < N2): + if x1[index1+1] < x2[index2+1]: + index1 += 1 + index += 1 + x_new[index] = x1[index1] + y_new[index] = y1[index1] + mp_new[index] = mp1[index1] + elif x1[index1+1] > x2[index2+1]: + index2 += 1 + index += 1 + x_new[index] = x2[index2] + y_new[index] = y2[index2] + mp_new[index] = mp2[index2] + else: # x1[index1+1] == x2[index2+1] + index1 += 1 + index2 += 1 + index += 1 + x_new[index] = x1[index1] + y_new[index] = y1[index1] + y2[index2] + mp_new[index] = mp1[index1] + mp2[index2] + # one array reached the end -> copy the contents of the other to the end + if index1+1 < N1: + x_new[index+1:index+1+N1-index1] = x1[index1+1:] + y_new[index+1:index+1+N1-index1] = y1[index1+1:] + mp_new[index+1:index+1+N1-index1] = mp1[index1+1:] + index += N1-index1 + elif index2+1 < N2: + x_new[index+1:index+1+N2-index2] = x2[index2+1:] + y_new[index+1:index+1+N2-index2] = y2[index2+1:] + mp_new[index+1:index+1+N2-index2] = mp2[index2+1:] + index += N2-index2 + else: # both arrays reached the end simultaneously + x_new[index+1] = x1[-1] + y_new[index+1] = y1[-1] + y2[-1] + mp_new[index+1] = mp1[-1] + mp2[-1] + index += 1 + + y_new[0] = y_new[1] + mp_new[0] = mp_new[1] + + # the last value is again the end of the interval + # only use the data that was actually filled + return x_new[:index+1], y_new[:index+1], mp_new[:index+1] |