Method addEdge

SRC/graph/graph/Graph.cpp:184–220

// graph. Returns $0$ if successful, a negative number if not.

int 
Graph::addEdge(int vertexTag, int otherVertexTag)
{
    // get pointers to the vertices, if one does not exist return

    Vertex *vertex1 = this->getVertexPtr(vertexTag);
    Vertex *vertex2 = this->getVertexPtr(otherVertexTag);
    if ((vertex1 == 0) || (vertex2 == 0)) {
	opserr << "WARNING Graph::addEdge() - one or both of the vertices ";
	opserr << vertexTag << " " << otherVertexTag << " not in Graph\n";
	return -1;
    }

    // add an edge to each vertex
    int result = vertex1->addEdge(otherVertexTag);
	if (result == 1)
		return 0;  // already there
	else if (result == 0) {  // added to vertexTag now add to other
		if ((result = vertex2->addEdge(vertexTag)) == 0) {
			numEdge++;
		}
		else {
			opserr << " WARNING Graph::addEdge() - " << vertexTag;
			opserr << " added to " << otherVertexTag;
			opserr << " adjacency - but already there in otherVertexTag!.\n";
			opserr << *this; exit(0);
			return -2;
		}
	} else {
			opserr << " WARNING Graph::addEdge() - " << vertexTag;
			opserr << " added to " << otherVertexTag;
			opserr << " adjacency - but not vica versa!.\n";
			opserr << *this; exit(0);
			return -2;
	}
    return result;
}

void
Graph::startAddEdge() {