void FlowNetwork::calculateFlow(const Network& network, const Config& config)
{
std::cout << "Calculating global flow... ";
// Prepare data in sequence containers for fast access of individual elements
unsigned int numNodes = network.numNodes();
m_nodeOutDegree.assign(numNodes, 0);
m_sumLinkOutWeight.assign(numNodes, 0.0);
m_nodeFlow.assign(numNodes, 0.0);
m_nodeTeleportRates.assign(numNodes, 0.0);
const LinkMap& linkMap = network.linkMap();
unsigned int numLinks = network.numLinks();
m_flowLinks.resize(numLinks);
double totalLinkWeight = network.totalLinkWeight();
double sumUndirLinkWeight = 2 * totalLinkWeight - network.totalSelfLinkWeight();
unsigned int linkIndex = 0;
for (LinkMap::const_iterator linkIt(linkMap.begin()); linkIt != linkMap.end(); ++linkIt)
{
unsigned int linkEnd1 = linkIt->first;
const std::map<unsigned int, double>& subLinks = linkIt->second;
for (std::map<unsigned int, double>::const_iterator subIt(subLinks.begin()); subIt != subLinks.end(); ++subIt, ++linkIndex)
{
unsigned int linkEnd2 = subIt->first;
double linkWeight = subIt->second;
++m_nodeOutDegree[linkEnd1];
m_sumLinkOutWeight[linkEnd1] += linkWeight;
if (linkEnd1 != linkEnd2)
{
// Possibly aggregate if no self-link
if (config.isUndirected()) {
m_sumLinkOutWeight[linkEnd2] += linkWeight;
++m_nodeOutDegree[linkEnd2];
}
if (!config.outdirdir)
m_nodeFlow[linkEnd2] += linkWeight / sumUndirLinkWeight;
}
m_nodeFlow[linkEnd1] += linkWeight / sumUndirLinkWeight;
m_flowLinks[linkIndex] = Link(linkEnd1, linkEnd2, linkWeight);
}
}
if (config.rawdir)
{
// Treat the link weights as flow (after global normalization) and
// do one power iteration to set the node flow
m_nodeFlow.assign(numNodes, 0.0);
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
Link& link = *linkIt;
link.flow /= totalLinkWeight;
m_nodeFlow[link.target] += link.flow;
}
//Normalize node flow
double sumNodeRank = 0.0;
for (unsigned int i = 0; i < numNodes; ++i)
sumNodeRank += m_nodeFlow[i];
for (unsigned int i = 0; i < numNodes; ++i)
m_nodeFlow[i] /= sumNodeRank;
std::cout << "using directed links with raw flow... done!" << std::endl;
std::cout << "Total link weight: " << totalLinkWeight << "\n";
return;
}
if (!config.directed)
{
if (config.undirdir || config.outdirdir)
{
//Take one last power iteration
std::vector<double> nodeFlowSteadyState(m_nodeFlow);
m_nodeFlow.assign(numNodes, 0.0);
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
Link& link = *linkIt;
m_nodeFlow[link.target] += nodeFlowSteadyState[link.source] * link.flow / m_sumLinkOutWeight[link.source];
}
//Normalize node flow
double sumNodeRank = 0.0;
for (unsigned int i = 0; i < numNodes; ++i)
sumNodeRank += m_nodeFlow[i];
for (unsigned int i = 0; i < numNodes; ++i)
m_nodeFlow[i] /= sumNodeRank;
// Update link data to represent flow instead of weight
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
Link& link = *linkIt;
link.flow *= nodeFlowSteadyState[link.source] / m_sumLinkOutWeight[link.source] / sumNodeRank;
}
}
else // undirected
{
for (unsigned int i = 0; i < numLinks; ++i)
m_flowLinks[i].flow /= sumUndirLinkWeight;
}
if (config.outdirdir)
std::cout << "counting only ingoing links... done!" << std::endl;
else
std::cout << "using undirected links" << (config.undirdir? ", switching to directed after steady state... done!" :
"... done!") << std::endl;
return;
}
std::cout << "using " << (config.recordedTeleportation ? "recorded" : "unrecorded") << " teleportation to " <<
(config.teleportToNodes ? "nodes" : "links") << "... " << std::flush;
// Calculate the teleport rate distribution
if (config.teleportToNodes)
{
const std::vector<double>& nodeWeights = network.nodeWeights();
if (nodeWeights.empty())
{
double rate = 1.0 / numNodes;
for (unsigned int i = 0; i < numNodes; ++i)
m_nodeTeleportRates[i] = rate;
}
else
{
for (unsigned int i = 0; i < numNodes; ++i)
m_nodeTeleportRates[i] = nodeWeights[i] / network.sumNodeWeights();
}
}
else // Teleport to nodes
{
// Teleport proportionally to out-degree, or in-degree if recorded teleportation.
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
unsigned int toNode = config.recordedTeleportation ? linkIt->target : linkIt->source;
m_nodeTeleportRates[toNode] += linkIt->flow / totalLinkWeight;
}
}
// Normalize link weights with respect to its source nodes total out-link weight;
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
linkIt->flow /= m_sumLinkOutWeight[linkIt->source];
}
// Collect dangling nodes
std::vector<unsigned int> danglings;
for (unsigned int i = 0; i < numNodes; ++i)
{
if (m_nodeOutDegree[i] == 0)
danglings.push_back(i);
}
// Calculate PageRank
std::vector<double> nodeFlowTmp(numNodes, 0.0);
unsigned int numIterations = 0;
double alpha = config.teleportationProbability;
double beta = 1.0 - alpha;
double sqdiff = 1.0;
double danglingRank = 0.0;
do
{
// Calculate dangling rank
danglingRank = 0.0;
for (std::vector<unsigned int>::iterator danglingIt(danglings.begin()); danglingIt != danglings.end(); ++danglingIt)
{
danglingRank += m_nodeFlow[*danglingIt];
}
// Flow from teleportation
for (unsigned int i = 0; i < numNodes; ++i)
{
nodeFlowTmp[i] = (alpha + beta*danglingRank) * m_nodeTeleportRates[i];
}
// Flow from links
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
Link& link = *linkIt;
nodeFlowTmp[link.target] += beta * link.flow * m_nodeFlow[link.source];
}
// Update node flow from the power iteration above and check if converged
double sum = 0.0;
double sqdiff_old = sqdiff;
sqdiff = 0.0;
for (unsigned int i = 0; i < numNodes; ++i)
{
sum += nodeFlowTmp[i];
sqdiff += std::abs(nodeFlowTmp[i] - m_nodeFlow[i]);
m_nodeFlow[i] = nodeFlowTmp[i];
}
// Normalize if needed
if (std::abs(sum - 1.0) > 1.0e-10)
{
std::cout << "(Normalizing ranks after " << numIterations << " power iterations with error " << (sum-1.0) << ") ";
for (unsigned int i = 0; i < numNodes; ++i)
{
m_nodeFlow[i] /= sum;
}
}
// Perturb the system if equilibrium
if(sqdiff == sqdiff_old)
{
alpha += 1.0e-10;
beta = 1.0 - alpha;
}
numIterations++;
} while((numIterations < 200) && (sqdiff > 1.0e-15 || numIterations < 50));
double sumNodeRank = 1.0;
if (!config.recordedTeleportation)
{
//Take one last power iteration excluding the teleportation (and normalize node flow to sum 1.0)
sumNodeRank = 1.0 - danglingRank;
m_nodeFlow.assign(numNodes, 0.0);
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
Link& link = *linkIt;
m_nodeFlow[link.target] += link.flow * nodeFlowTmp[link.source] / sumNodeRank;
}
beta = 1.0;
}
// Update the links with their global flow from the PageRank values. (Note: beta is set to 1 if unrec)
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
linkIt->flow *= beta * nodeFlowTmp[linkIt->source] / sumNodeRank;
}
std::cout << "done in " << numIterations << " iterations!" << std::endl;
}
void MemFlowNetwork::calculateFlow(const Network& net, const Config& config)
{
if (!config.isMemoryNetwork())
{
FlowNetwork::calculateFlow(net, config);
return;
}
Log() << "Calculating global flow... " << std::flush;
const MemNetwork& network = static_cast<const MemNetwork&>(net);
// Prepare data in sequence containers for fast access of individual elements
unsigned int numM2Nodes = network.numM2Nodes();
// Copy to be able to modify
std::vector<double> nodeOutDegree(network.outDegree());
std::vector<double> sumLinkOutWeight(network.sumLinkOutWeight());
m_nodeFlow.assign(numM2Nodes, 0.0);
m_nodeTeleportRates.assign(numM2Nodes, 0.0);
const MemNetwork::M2LinkMap& linkMap = network.m2LinkMap();
unsigned int numLinks = network.numM2Links();
m_flowLinks.resize(numLinks);
double totalM2LinkWeight = network.totalM2LinkWeight();
double sumUndirLinkWeight = 2 * totalM2LinkWeight - network.totalMemorySelfLinkWeight();
unsigned int linkIndex = 0;
const MemNetwork::M2NodeMap& nodeMap = network.m2NodeMap();
for (MemNetwork::M2LinkMap::const_iterator linkIt(linkMap.begin()); linkIt != linkMap.end(); ++linkIt)
{
const M2Node& m2source = linkIt->first;
const std::map<M2Node, double>& subLinks = linkIt->second;
for (std::map<M2Node, double>::const_iterator subIt(subLinks.begin()); subIt != subLinks.end(); ++subIt, ++linkIndex)
{
const M2Node& m2target = subIt->first;
double linkWeight = subIt->second;
// Get the indices for the m2 nodes
MemNetwork::M2NodeMap::const_iterator nodeMapIt = nodeMap.find(m2source);
if (nodeMapIt == nodeMap.end())
throw InputDomainError(io::Str() << "Couldn't find mapped index for source M2 node " << m2source);
unsigned int sourceIndex = nodeMapIt->second;
nodeMapIt = nodeMap.find(m2target);
if (nodeMapIt == nodeMap.end())
throw InputDomainError(io::Str() << "Couldn't find mapped index for target M2 node " << m2target);
unsigned int targetIndex = nodeMapIt->second;
m_nodeFlow[sourceIndex] += linkWeight;// / sumUndirLinkWeight;
m_flowLinks[linkIndex] = Link(sourceIndex, targetIndex, linkWeight);
if (sourceIndex != targetIndex && !config.outdirdir)
m_nodeFlow[targetIndex] += linkWeight;// / sumUndirLinkWeight;
}
}
m_m2nodes.resize(numM2Nodes);
for (MemNetwork::M2NodeMap::const_iterator m2nodeIt(nodeMap.begin()); m2nodeIt != nodeMap.end(); ++m2nodeIt)
{
m_m2nodes[m2nodeIt->second] = m2nodeIt->first;
}
unsigned int numM1Nodes = network.numNodes();
typedef std::multimap<double, unsigned int> PhysToMemWeightMap;
std::vector<PhysToMemWeightMap> netPhysToMem(numM1Nodes);
const LinkMap& m1LinkMap = network.linkMap();
// Map middle column in trigrams to target m2 nodes (source to link for m1 links)
for (LinkMap::const_iterator linkIt(m1LinkMap.begin()); linkIt != m1LinkMap.end(); ++linkIt)
{
unsigned int linkEnd1 = linkIt->first;
const std::map<unsigned int, double>& subLinks = linkIt->second;
for (std::map<unsigned int, double>::const_iterator subIt(subLinks.begin()); subIt != subLinks.end(); ++subIt)
{
unsigned int linkEnd2 = subIt->first;
double linkWeight = subIt->second;
MemNetwork::M2NodeMap::const_iterator m2it = nodeMap.find(M2Node(linkEnd1, linkEnd2));
if (m2it == nodeMap.end())
throw InputDomainError(io::Str() << "Memory node (" << linkEnd1 << ", " << linkEnd2 << ") not indexed!");
unsigned int m2nodeIndex = m2it->second;
PhysToMemWeightMap& physMap = netPhysToMem[linkEnd1];
physMap.insert(std::make_pair(linkWeight, m2nodeIndex));
}
}
// Add M1 flow to dangling M2 nodes
unsigned int numDanglingM2Nodes = 0;
unsigned int numSelfLinks = 0;
double sumExtraLinkWeight = 0.0;
for (unsigned int i = 0; i < numM2Nodes; ++i)
{
if (nodeOutDegree[i] == 0)
{
++numDanglingM2Nodes;
// We are in physIndex, lookup all mem nodes in that physical node
// and add a link to the target node of those mem nodes (pre-mapped above)
const PhysToMemWeightMap& physToMem = netPhysToMem[m_m2nodes[i].physIndex];
for(PhysToMemWeightMap::const_iterator it = physToMem.begin(); it != physToMem.end(); it++)
{
unsigned int from = i;
unsigned int to = it->second;
double linkWeight = it->first;
if(linkWeight > 0.0) {
if(from == to) {
++numSelfLinks;
}
else {
++nodeOutDegree[from];
sumLinkOutWeight[from] += linkWeight;
sumExtraLinkWeight += linkWeight;
m_nodeFlow[from] += linkWeight;
if (config.isUndirected()) {
++nodeOutDegree[to];
sumLinkOutWeight[to] += linkWeight;
}
if (!config.outdirdir) {
m_nodeFlow[to] += linkWeight;
}
if (from >= numM2Nodes || to >= numM2Nodes) {
Log() << "\nRange error adding dangling links " << from << " " << to << " !!!";
}
m_flowLinks.push_back(Link(from, to, linkWeight));
}
}
}
}
}
if (m_flowLinks.size() - numLinks != 0)
Log() << "\n -> Added " << (m_flowLinks.size() - numLinks) << " links to " <<
numDanglingM2Nodes << " dangling memory nodes -> " << m_flowLinks.size() << " links" << std::flush;
totalM2LinkWeight += sumExtraLinkWeight;
sumUndirLinkWeight = 2 * totalM2LinkWeight - network.totalMemorySelfLinkWeight();
numLinks = m_flowLinks.size();
// Normalize node flow
for (unsigned int i = 0; i < numM2Nodes; ++i)
m_nodeFlow[i] /= sumUndirLinkWeight;
if (config.rawdir)
{
// Treat the link weights as flow (after global normalization) and
// do one power iteration to set the node flow
m_nodeFlow.assign(numM2Nodes, 0.0);
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
Link& link = *linkIt;
link.flow /= totalM2LinkWeight;
m_nodeFlow[link.target] += link.flow;
}
//Normalize node flow
double sumNodeRank = 0.0;
for (unsigned int i = 0; i < numM2Nodes; ++i)
sumNodeRank += m_nodeFlow[i];
for (unsigned int i = 0; i < numM2Nodes; ++i)
m_nodeFlow[i] /= sumNodeRank;
Log() << "\n -> Using directed links with raw flow.";
Log() << "\n -> Total link weight: " << totalM2LinkWeight << ".";
Log() << std::endl;
return;
}
if (!config.directed)
{
if (config.undirdir || config.outdirdir)
{
//Take one last power iteration
std::vector<double> nodeFlowSteadyState(m_nodeFlow);
m_nodeFlow.assign(numM2Nodes, 0.0);
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
Link& link = *linkIt;
m_nodeFlow[link.target] += nodeFlowSteadyState[link.source] * link.flow / sumLinkOutWeight[link.source];
}
//Normalize node flow
double sumNodeRank = 0.0;
for (unsigned int i = 0; i < numM2Nodes; ++i)
sumNodeRank += m_nodeFlow[i];
for (unsigned int i = 0; i < numM2Nodes; ++i)
m_nodeFlow[i] /= sumNodeRank;
// Update link data to represent flow instead of weight
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
Link& link = *linkIt;
link.flow *= nodeFlowSteadyState[link.source] / sumLinkOutWeight[link.source] / sumNodeRank;
}
}
else // undirected
{
for (unsigned int i = 0; i < numLinks; ++i)
m_flowLinks[i].flow /= sumUndirLinkWeight;
}
if (config.outdirdir)
Log() << "\n -> Counting only ingoing links.";
else
Log() << "\n -> Using undirected links" << (config.undirdir? ", switching to directed after steady state." :
".");
Log() << std::endl;
return;
}
Log() << "\n -> Using " << (config.recordedTeleportation ? "recorded" : "unrecorded") << " teleportation to memory " <<
(config.teleportToNodes ? "nodes" : "links") << " " << std::flush;
if (config.originallyUndirected)
{
if (config.recordedTeleportation || !config.teleportToNodes)
Log() << "(warning: should be unrecorded teleportation to nodes to correspond to undirected flow on physical network) " << std::flush;
else
Log() << "(corresponding to undirected flow on physical network) " << std::flush;
}
// Calculate the teleport rate distribution
if (config.teleportToNodes)
{
const std::vector<double>& nodeWeights = network.m2NodeWeights();
for (unsigned int i = 0; i < numM2Nodes; ++i) {
// m_nodeTeleportRates[i] = sumLinkOutWeight[i] / totalM2LinkWeight;
// Use original m2 weights (without m1-completed weights for dangling m2 nodes)
m_nodeTeleportRates[i] = nodeWeights[i] / network.totalM2NodeWeight();
}
}
else // Teleport to links
{
// Teleport proportionally to out-degree, or in-degree if recorded teleportation.
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
unsigned int toNode = config.recordedTeleportation ? linkIt->target : linkIt->source;
m_nodeTeleportRates[toNode] += linkIt->flow / totalM2LinkWeight;
}
}
// Normalize link weights with respect to its source nodes total out-link weight;
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
linkIt->flow /= sumLinkOutWeight[linkIt->source];
}
// Collect dangling nodes
std::vector<unsigned int> danglings;
for (unsigned int i = 0; i < numM2Nodes; ++i)
{
if (nodeOutDegree[i] == 0)
danglings.push_back(i);
}
// Calculate PageRank
std::vector<double> nodeFlowTmp(numM2Nodes, 0.0);
unsigned int numIterations = 0;
double alpha = config.teleportationProbability;
double beta = 1.0 - alpha;
double sqdiff = 1.0;
double danglingRank = 0.0;
do
{
// Calculate dangling rank
danglingRank = 0.0;
for (std::vector<unsigned int>::iterator danglingIt(danglings.begin()); danglingIt != danglings.end(); ++danglingIt)
{
danglingRank += m_nodeFlow[*danglingIt];
}
// Flow from teleportation
for (unsigned int i = 0; i < numM2Nodes; ++i)
{
nodeFlowTmp[i] = (alpha + beta*danglingRank) * m_nodeTeleportRates[i];
}
// Flow from links
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
Link& link = *linkIt;
nodeFlowTmp[link.target] += beta * link.flow * m_nodeFlow[link.source];
}
// Update node flow from the power iteration above and check if converged
double sum = 0.0;
double sqdiff_old = sqdiff;
sqdiff = 0.0;
for (unsigned int i = 0; i < numM2Nodes; ++i)
{
sum += nodeFlowTmp[i];
sqdiff += std::abs(nodeFlowTmp[i] - m_nodeFlow[i]);
m_nodeFlow[i] = nodeFlowTmp[i];
}
// Normalize if needed
if (std::abs(sum - 1.0) > 1.0e-10)
{
Log() << "(Normalizing ranks after " << numIterations << " power iterations with error " << (sum-1.0) << ") ";
for (unsigned int i = 0; i < numM2Nodes; ++i)
{
m_nodeFlow[i] /= sum;
}
std::cerr << "DEBUG BREAK!!" << std::endl;
break;
}
// Perturb the system if equilibrium
if(sqdiff == sqdiff_old)
{
alpha += 1.0e-10;
beta = 1.0 - alpha;
}
numIterations++;
} while((numIterations < 200) && (sqdiff > 1.0e-15 || numIterations < 50));
double sumNodeRank = 1.0;
if (!config.recordedTeleportation)
{
//Take one last power iteration excluding the teleportation (and normalize node flow to sum 1.0)
sumNodeRank = 1.0 - danglingRank;
m_nodeFlow.assign(numM2Nodes, 0.0);
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
Link& link = *linkIt;
m_nodeFlow[link.target] += link.flow * nodeFlowTmp[link.source] / sumNodeRank;
}
beta = 1.0;
}
// Update the links with their global flow from the PageRank values. (Note: beta is set to 1 if unrec)
for (LinkVec::iterator linkIt(m_flowLinks.begin()); linkIt != m_flowLinks.end(); ++linkIt)
{
linkIt->flow *= beta * nodeFlowTmp[linkIt->source] / sumNodeRank;
}
Log() << "\n -> PageRank calculation done in " << numIterations << " iterations." << std::endl;
}