split graph code into own file

include/graph.c

@@ -0,0 +1,148 @@
+typedef struct{
+	PyObject_HEAD
+	Index node_count;
+	Index* pre_neighbor_offsets;
+	PyArrayObject* edge_list;
+} Graph;
+
+
+static void Graph_dealloc(Graph* graph){
+	free(graph->pre_neighbor_offsets);
+	Py_DECREF(graph->edge_list);
+	Py_TYPE(graph)->tp_free((PyObject*)graph);
+}
+
+
+static PyObject* Graph_new(PyTypeObject* type, PyObject* args, PyObject* kwds){
+	Index node_count;
+	PyArrayObject* edges;
+
+	//	ASSUMPTION: edge list should be sorted in the second argument or destination
+
+	if(!PyArg_ParseTuple(args, "OI", (PyObject**)&edges, &node_count)){
+		puts("no new graph without correct args");
+		return NULL;
+	}
+
+
+
+	// TODO: check edges.dtype in {np.uint32, np.uint64}
+
+
+	Graph* graph = (Graph*) type->tp_alloc(type, 0);
+
+	if(graph!=NULL){
+		// NOTE: if ASSUMPTION in count_neighbors is wrong, memory needs to be zeroed out before starting counting
+		graph->pre_neighbor_offsets = (Index*)malloc((node_count+1)*sizeof(Index));
+
+
+
+		ASSERT(graph->pre_neighbor_offsets);
+	}
+
+	return (PyObject*)graph;
+}
+
+
+
+
+
+
+
+
+
+
+static int Graph_init(Graph* graph, PyObject* args, PyObject* kwds){
+	PyArrayObject* edges;
+	Index node_count;
+
+	//	ASSUMPTION: edge list should be sorted in the second argument
+
+	if(!PyArg_ParseTuple(args, "OI", (PyObject**)&edges, &node_count)){
+		puts("couldn't parse edge list");
+		return -1;
+	}
+
+	graph->node_count = node_count;
+
+	graph->edge_list = edges;
+
+	Py_INCREF(edges);
+
+
+
+
+
+	// TODO: MT or GPU
+	for(Index i=0; i<graph->node_count+1; i++){
+    	graph->pre_neighbor_offsets[i]=0;
+    }
+
+    Index edge_count = (Index)PyArray_DIM(edges, 1);
+
+	for(Index e=0; e<edge_count; e++){
+		Node dst_node = *((Node*)PyArray_GETPTR2(edges, 1, e));
+		graph->pre_neighbor_offsets[Node_To_Index(dst_node)+1]++;
+    }
+
+    neighbor_counts_to_offsets(graph->node_count, graph->pre_neighbor_offsets);
+
+	return 0;
+}
+
+static Node src_node_at(Graph* g, Index i){
+	ASSERT(i < g->pre_neighbor_offsets[g->node_count]);
+
+	return *((Node*)PyArray_GETPTR2(g->edge_list, 0, i));
+}
+
+static Node dst_node_at(Graph* g, Index i){
+	ASSERT(i < g->pre_neighbor_offsets[g->node_count]);
+	return *((Node*)PyArray_GETPTR2(g->edge_list, 1, i));
+}
+
+static PyObject* Graph_print(Graph* graph, PyObject *Py_UNUSED(ignored)){
+	for(Index i=0;i<graph->node_count;i++){
+		Index c = graph->pre_neighbor_offsets[i+1]-graph->pre_neighbor_offsets[i];
+		Index o=graph->pre_neighbor_offsets[i];
+
+		for(Index ii=0; ii<c; ii++)
+			printf("(%u, %u), ", src_node_at(graph, o+ii), dst_node_at(graph, o+ii));
+	}
+	printf("\n");
+
+	Py_RETURN_NONE;
+}
+
+static PyObject* Graph_preneighborhood_count(Graph* graph, PyObject* args){
+	Node n;
+	if(!PyArg_ParseTuple(args, "I", &n)){
+		printf("If you don't provide proper arguments, you can't have any neighbor sampling.\nHow can you have any neighbor sampling if you don't provide proper arguments?\n");
+		return NULL;
+	}
+
+	Index pre_neighbor_count = graph->pre_neighbor_offsets[Node_To_Index(n)+1]-graph->pre_neighbor_offsets[Node_To_Index(n)];
+
+	return PyLong_FromIndex(pre_neighbor_count);
+}
+
+
+
+static PyMethodDef Graph_methods[] = {
+	{"print", (PyCFunction)Graph_print, METH_NOARGS, "print the graph"},
+	{"preneighborhood_count", (PyCFunction)Graph_preneighborhood_count, METH_VARARGS, "get the size of the pre-neighborhood of a node within the graph"},
+	{NULL}
+};
+
+static PyTypeObject GraphType = {
+	PyVarObject_HEAD_INIT(NULL, 0)
+    .tp_name = "GMSamplers.Graph",
+    .tp_doc = PyDoc_STR("GMSamplers graph"),
+    .tp_basicsize = sizeof(Graph),
+    .tp_itemsize = 0,
+    .tp_flags = Py_TPFLAGS_DEFAULT,
+    .tp_new = Graph_new,
+    .tp_init = (initproc) Graph_init,
+    .tp_dealloc = (destructor) Graph_dealloc,
+    .tp_methods = Graph_methods
+};