void TripletConnection::propagate_backward()
{
if (stdp_active) {
SpikeContainer::const_iterator spikes_end = dst->get_spikes_immediate()->end();
// loop over all spikes
for (SpikeContainer::const_iterator spike = dst->get_spikes_immediate()->begin() ; // spike = post_spike
spike != spikes_end ;
++spike ) {
// Since we need the local id of the postsynaptic neuron that spiked
// multiple times, we translate it here:
NeuronID translated_spike = dst->global2rank(*spike);
// loop over all presynaptic partners
for (const NeuronID * c = bkw->get_row_begin(*spike) ; c != bkw->get_row_end(*spike) ; ++c ) {
#ifdef CODE_ACTIVATE_PREFETCHING_INTRINSICS
// prefetches next memory cells to reduce number of last-level cache misses
_mm_prefetch((const char *)bkw_data[c-bkw_ind+2], _MM_HINT_NTA);
#endif
// computes plasticity update
AurynWeight * weight = bkw->get_data(c);
*weight += dw_post(*c,translated_spike);
// clips too large weights
if (*weight>get_max_weight()) *weight=get_max_weight();
}
}
}
}
void TripletConnection::propagate_backward()
{
if (stdp_active) {
SpikeContainer::const_iterator spikes_end = dst->get_spikes_immediate()->end();
// process spikes
for (SpikeContainer::const_iterator spike = dst->get_spikes_immediate()->begin() ; // spike = post_spike
spike != spikes_end ; ++spike ) {
NeuronID translated_spike = dst->global2rank(*spike); // only to be used for post traces
for (NeuronID * c = bkw->get_row_begin(*spike) ; c != bkw->get_row_end(*spike) ; ++c ) {
_mm_prefetch(bkw_data[c-bkw_ind+1], _MM_HINT_NTA); // tested this and this and NTA directly here gave the best performance on the SUN
*bkw_data[c-bkw_ind] = *bkw_data[c-bkw_ind] + dw_post(*c,translated_spike);
if (*bkw_data[c-bkw_ind]>get_max_weight()) *bkw_data[c-bkw_ind]=get_max_weight();
}
}
}
}
inline void SymmetricSTDPConnection::propagate_backward()
{
NeuronID * ind = bkw->get_row_begin(0); // first element of index array
AurynWeight ** data = bkw->get_data_begin();
SpikeContainer::const_iterator spikes_end = dst->get_spikes_immediate()->end();
for (SpikeContainer::const_iterator spike = dst->get_spikes_immediate()->begin() ; // spike = post_spike
spike != spikes_end ; ++spike ) {
for (NeuronID * c = bkw->get_row_begin(*spike) ; c != bkw->get_row_end(*spike) ; ++c ) {
#ifdef CODE_ACTIVATE_PREFETCHING_INTRINSICS
_mm_prefetch((const char *)data[c-ind+2], _MM_HINT_NTA);
#endif
*data[c-ind] += dw_post(*c);
if (*data[c-ind] > get_max_weight()) {
*data[c-ind] = get_max_weight();
}
}
}
}
