Spikey Bug: Targeting excitatory and inhibitory synapses

spikey_bug_inh_exc_tar.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Test script which demonstrates a Bug in Spikey:
# If a SpikeSourceArray targets both excitatory and inhibitory synapses (of
# different target neurons), only inhibitory connections are made.

import numpy as np
import pyNN.hardware.spikey as sim

sim.setup()

n_src = 8 # Neurons in the source population
n_tar = 8 # Neurons in the target population
w = 4.0 * sim.minExcWeight() # Synaptic weight
runtime = 10.0e3  # Runtime of the simulation
spikes = np.arange(0, runtime, 1000.0 / 100.0).tolist() # 10 Hz fire rate

# Create the source and target populations
pop_src = sim.Population(n_src, sim.SpikeSourceArray, {"spike_times": spikes
                                                         })
pop_tar = sim.Population(n_tar, sim.IF_facets_hardware1)

# Excitatory connection from src to even neurons in tar
sim.Projection(pop_src,
               pop_tar,
               sim.FromListConnector([(i, j, w, 0.1)
                                      for i in xrange(0, n_src) for j in
                                      xrange(0, n_tar, 2)]),
               target='excitatory')

# Inhibitory connection from src to odd neurons in tar
# If present, output fire rate is zero -- although the output rate should not
# change at all
sim.Projection(pop_src,
               pop_tar,
               sim.FromListConnector([(i, j, w, 0.1)
                                      for i in xrange(0, n_src) for j in
                                      xrange(1, n_tar, 2)]),
               target='inhibitory')

# Record output spikes, run the simulation and calculate the average output spike
pop_tar.record()
sim.run(runtime)
print "Average fire rate: " + str(float(len(pop_tar.getSpikes())) / n_tar /
                                  runtime * 1e3)