//description of a PGFT (TODO : better doc)
unsigned int levels;
std::vector<unsigned int> lowerLevelNodesNumber; // number of children by node
std::vector<unsigned int> upperLevelNodesNumber; // number of parents by node
std::vector<unsigned int> lowerLevelPortsNumber; // ports between each level l and l-1
//description of a PGFT (TODO : better doc)
unsigned int levels;
std::vector<unsigned int> lowerLevelNodesNumber; // number of children by node
std::vector<unsigned int> upperLevelNodesNumber; // number of parents by node
std::vector<unsigned int> lowerLevelPortsNumber; // ports between each level l and l-1