[igraph] renumbering input graph

[hazel vincent]

1.  I would like to renumber the nodes in my dataset before proceesing
it using igraph since it is actually a subset of the entire data. Some
functions tend to renumber vertices when a subset of the graph is
chosen. Can this kind of renumbering be done on the graph that we
supply, if it is a subset of the actual graph ?

2. Besides the normal DFS method to figure out all the paths between 2
nodes, is there any other efficient way to find all paths between 2
nodes using igraph ?

Thanks,
HD.