spike_buffer.cpp

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/* * Copyright (c) 2016 Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* 3. The names of its contributors may not be used to endorse or promote
*    products derived from this software without specific prior written
*    permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* *********************************************************************************************** *
* CARLsim
* created by: (MDR) Micah Richert, (JN) Jayram M. Nageswaran
* maintained by:
* (MA) Mike Avery <averym@uci.edu>
* (MB) Michael Beyeler <mbeyeler@uci.edu>,
* (KDC) Kristofor Carlson <kdcarlso@uci.edu>
* (TSC) Ting-Shuo Chou <tingshuc@uci.edu>
* (HK) Hirak J Kashyap <kashyaph@uci.edu>
*
* CARLsim v1.0: JM, MDR
* CARLsim v2.0/v2.1/v2.2: JM, MDR, MA, MB, KDC
* CARLsim3: MB, KDC, TSC
* CARLsim4: TSC, HK
* CARLsim5: HK, JX, KC
* CARLsim6: LN, JX, KC, KW
*
* CARLsim available from http://socsci.uci.edu/~jkrichma/CARLsim/
* Ver 12/31/2016
*/
#include <spike_buffer.h>

#include <vector>


// the size of an allocation chunk
#define MAX_CHUNK_SIZE 1024


class SpikeBuffer::Impl {
public:
    // +++++ PUBLIC METHODS: SETUP / TEAR-DOWN ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ //

    Impl(int minDelay, int maxDelay) : _currNodeId(0), _spikeBufFront(maxDelay+1), 
        _spikeBufBack(maxDelay+1), _chunkBuf(0), _currFreeChunkId(NULL), _nextFreeNodeId(0), _nextFreeChunkId(0),
        _recycledNodes(NULL)
    {
        reset(minDelay, maxDelay);
    }
    
    ~Impl() {
        for (size_t i=0; i<_chunkBuf.size(); i++) {
            delete[] _chunkBuf[i];
        }
    }

    void reset(int minDelay, int maxDelay) {
        init(maxDelay + minDelay);

        for (size_t i=0; i<_spikeBufFront.size(); i++) {
            _spikeBufFront[i] = NULL;
            _spikeBufBack[i] = NULL;
        }

        _currFreeChunkId = _chunkBuf[0];
        _nextFreeChunkId = 1;

        _currNodeId = 0;
        _nextFreeNodeId = 0;
        _recycledNodes = NULL;
    }



    // +++++ PUBLIC METHODS +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ //

    // points to front of buffer
    SpikeIterator front(int stepOffset=0) {
        return SpikeIterator(_spikeBufFront[(_currNodeId + stepOffset + length()) % length()]);
    };

    // End iterator corresponding to beginSynapseGroups
    SpikeIterator back() {
        return SpikeIterator(NULL);
    };

    // retrieve actual length of buffer
    size_t length() {
        return _spikeBufFront.size();
    }
    
    // schedule a spike at t + delay for neuron neurId
    void schedule(int neurId, int grpId, unsigned short int delay) {
        SpikeNode* n = getFreeNode();

        int writeIdx = (_currNodeId+delay) % _spikeBufFront.size();

        n->neurId = neurId;
        n->grpId = grpId;
        n->delay = delay;
        n->next = NULL;
        if (_spikeBufFront[writeIdx] == NULL) {
            _spikeBufFront[writeIdx] = n;
            _spikeBufBack[writeIdx] = n;
        } else {
            _spikeBufBack[writeIdx]->next = n;
            _spikeBufBack[writeIdx] = n;
        }
    }

    void step() {
    // move the solts of _currNodeId to recycled slots
        if (_spikeBufFront[_currNodeId] != NULL) {
            _spikeBufBack[_currNodeId]->next = _recycledNodes;
            _recycledNodes = _spikeBufFront[_currNodeId];
        }
    
        // mark current index as processed
        _spikeBufFront[_currNodeId] = NULL;
        _spikeBufBack[_currNodeId] = NULL;
        _currNodeId = (_currNodeId + 1) % _spikeBufFront.size();
    }


private:
    void init(size_t maxDelaySteps) {
        if (_spikeBufFront.size() != maxDelaySteps + 1) {
            _spikeBufFront.resize(maxDelaySteps + 1);
            _spikeBufBack.resize(maxDelaySteps + 1);
        }
        if (_chunkBuf.size() < 1) {
            _chunkBuf.reserve(10);
            _chunkBuf.resize(0);
            _chunkBuf.push_back(new SpikeNode[MAX_CHUNK_SIZE]);
        }
    }

    SpikeNode* getFreeNode() {
        SpikeNode* n;
        if (_recycledNodes != NULL) {
            // find a recycled node
            n = _recycledNodes;
            _recycledNodes = _recycledNodes->next;
        } else if (_nextFreeNodeId < MAX_CHUNK_SIZE) {
            // as long as there is pre-allocated memory left: get a new slot from the current chunk
            n = &(_currFreeChunkId[_nextFreeNodeId++]);
        } else if (_nextFreeChunkId < _chunkBuf.size()) {
            // pre-allocated memory chunk is used up: go to next chunk
            _currFreeChunkId = _chunkBuf[_nextFreeChunkId++];
            n = &(_currFreeChunkId[0]);
            _nextFreeNodeId = 1;
        } else {
            // all chunks used up: need to allocate new one
            _currFreeChunkId = new SpikeNode[MAX_CHUNK_SIZE];
            _chunkBuf.push_back(_currFreeChunkId);

            _nextFreeChunkId++;
            _nextFreeNodeId = 1;
            n = &(_currFreeChunkId[0]);
        }
        return n;
    }

    int _currNodeId;

    std::vector<SpikeNode*> _spikeBufFront;

    std::vector<SpikeNode*> _spikeBufBack;

    std::vector<SpikeNode*> _chunkBuf;

    SpikeNode* _currFreeChunkId;

    int _nextFreeNodeId;

    size_t _nextFreeChunkId;

    SpikeNode* _recycledNodes;
};


// ****************************************************************************************************************** //
// SPIKEBUFFER API IMPLEMENTATION
// ****************************************************************************************************************** //

// constructor / destructor
SpikeBuffer::SpikeBuffer(int minDelay, int maxDelay) : 
    _impl( new Impl(minDelay, maxDelay) ) {}
SpikeBuffer::~SpikeBuffer() { delete _impl; }

// public methods
void SpikeBuffer::schedule(int neurId, int grpId, unsigned short int delay) { _impl->schedule(neurId, grpId, delay); }
void SpikeBuffer::step() { _impl->step(); }
void SpikeBuffer::reset(int minDelay, int maxDelay) { _impl->reset(minDelay, maxDelay); }
size_t SpikeBuffer::length() { return _impl->length(); }
SpikeBuffer::SpikeIterator SpikeBuffer::front(int stepOffset) { return _impl->front(stepOffset); }
SpikeBuffer::SpikeIterator SpikeBuffer::back() { return _impl->back(); }