how to use stinger_rmat_edge_generator to generator base initial graph?

[GH15zzh]

For example, if I want to generate a basic graph of 700,000 vertices, 70 million edges, how should I use the stinger_rmat_edge_generator?
Using the command like this "./bin/stinger_rmat_edge_generator -n 10000 -x 1000000 -y 70" ?
However, the graph size is given by two parameters: scale and edge_factor.
So what's the relation between the command and the parameters?
And what are the right steps for generating basic graph?