Hi Todd ands louis manfredi, 
it seems that i don't have the same options with the right click, maybe my version is too old. 
Anyway, i took an initialyse array instead of and a graph. 
And it works very well, thanks very much. 
Only one thing more, on my graph, i can see for each value incoming, a triangular pictured. Do you know if it is possible to have a rectangular instead of ? 
Thank you very much, 
Cheers, 
Alexum.