Update hpvm-specification.md

hpvm/docs/hpvm-specification.md

@@ -8,10 +8,13 @@ A single static dataflow node represents multiple dynamic instances of the node,
 
 Each dataflow node in a DFG can either be a *leaf node* or an *internal node*. An internal node contains a complete DFG, called a *child graph*, and the child graph itself can have internal nodes and/or leaf nodes.
 
-Internal nodes only create the structure of the child graph, and cannot include actual computation. The DFG cannot be modified at runtime except for the number of dynamic instances, which can be data dependent.
+Internal nodes only create the structure of the child graph, and cannot include actual computation. 
 
 Leaf nodes contain code expressing actual computations. Leaf nodes may contain instructions to query the structure of the underlying DFG, and any non host side HPVM operation for synchronization and memory allocation.
 
+Note that the graph is full interpreted at compile-time and  cannot be modified at runtime except for the number of dynamic instances, which can be data dependent.
+
+
 ## Dataflow Edge
 A *dataflow edge* from the output ```out``` of a source dataflow node ```Src``` to the input ```in``` of a sink dataflow node ```Dst``` describes the explicit data transfer requirements. ```Src``` and ```Dst``` node must belong to the same child graph, i.e. must be children of the same internal node.