Some information on the UI?

[gomaxlou]

What do the representatives mean?

[reaper47]

T is the graph's global time, most likely the elapsed time.
I is the number of iterations.
N is the number of nodes in the graph. The number within the square brackets is the number of visible nodes in your view port.
V is the graph's version.
FPS is the graph's frames per second.

[gomaxlou]

but the T , I always 0 like screenshot?

[reaper47]

It is indeed always 0 for some reason. Maybe there is a way to activate those values.