Function Proc_BFS_Invoke

src/procedures/proc_bfs.c:66–141

}

static ProcedureResult Proc_BFS_Invoke
(
	ProcedureCtx *ctx,
	const SIValue *args,
	const char **yield
) {
	// validate inputs
	ASSERT(ctx   !=  NULL);
	ASSERT(args  !=  NULL);

	if(array_len((SIValue *)args) != 3) return PROCEDURE_ERR;
	if(SI_TYPE(args[0]) != T_NODE                 ||   // source node
	   SI_TYPE(args[1]) != T_INT64                ||   // max level to iterate to, unlimited if 0
	   !(SI_TYPE(args[2]) & (T_NULL | T_STRING)))      // relationship type to traverse if not NULL
		return PROCEDURE_ERR;

	BFSCtx *bfs_ctx = ctx->privateData;
	_process_yield(bfs_ctx, yield);

	//--------------------------------------------------------------------------
	// Process inputs
	//--------------------------------------------------------------------------

	Node *source_node = args[0].ptrval;
	int64_t max_level = args[1].longval;
	const char *reltype = SIValue_IsNull(args[2]) ? NULL : args[2].stringval;

	GrB_Index src_id = ENTITY_GET_ID(source_node);

	// Get edge matrix and transpose matrix, if available.
	GrB_Matrix    R    =  NULL;
	GraphContext  *gc  =  QueryCtx_GetGraphCtx();

	if(reltype == NULL) {
		RG_Matrix_export(&R, Graph_GetAdjacencyMatrix(gc->g, false));
	} else {
		Schema *s = GraphContext_GetSchema(gc, reltype, SCHEMA_EDGE);
		// failed to find schema, first step will return NULL
		if(!s) return PROCEDURE_OK;

		bfs_ctx->reltype_id = s->id;
		RG_Matrix_export(&R, Graph_GetRelationMatrix(gc->g, s->id, false));
	}

	// if we're not collecting edges, pass a NULL parent pointer
	// so that the algorithm will not perform unnecessary work
	GrB_Vector V = GrB_NULL;  // vector of results
	GrB_Vector PI = GrB_NULL; // vector backtracking results to their parents
	GrB_Vector *pPI = Π
	if(!bfs_ctx->yield_edges) pPI = NULL;
	GrB_Info res = LG_BreadthFirstSearch_SSGrB(&V, pPI, R, src_id, NULL, max_level);
	ASSERT(res == GrB_SUCCESS);

	// remove all values with a level less than or equal to 1
	// values of 0 are not connected to the source, and values of 1 are the source
	GxB_Scalar thunk;
	GxB_Scalar_new(&thunk, GrB_UINT64);
	GxB_Scalar_setElement_UINT64(thunk, 0);