Root on LxPlus

ROOT
1

Dear Rooters,

I am a beginner of ROOT. My question might be very easy. I am using windows XP and want to use ROOT on LxPlus. For this puspose I am using putty and I can run ROOT with typing on LxPlus,

“[lxplus096] /afs/cern.ch/sw/lcg/external/root/5.16.00/win32_vc71_dbg > root.exe”

and ROOT work. I try to plot a graph with following command,

TF1 f1(“func1”,“sin(x)/x”,0,10);
f.Draw();

At this time, ROOT does not give any error. It gives

“TCanvas::MakeDefCanvas: created default TCanvas with name c1”

message but I could not see any graph on my screen.

Could you please let me know how can I fix this problem.

Thank you very much and kind regards.

2

Hi,

It is not possible to display graphics or GUI from a putty session. As lxplus is linux, it needs a X client/server architecture to display graphics. Windows (and putty) doesn’t know anything about X… (just try to start nedit from putty, you will see what I mean)
One solution could be to use a remote root session. To do so, just start a Root session on your Windows machine, and type “.R yourname@lxplus.cern.ch”. This will start a remote session on lxplus. Then, if you execute a script which create a TCanvas on the remote session, it will be displayed by the local one. This feature has been introduced recently and is only available in the last release of Root.

Cheers,
Bertrand.

3

Dear Bertrand,

Thank you for your reply. I write on ROOT

.R username@lxplus.cern.ch

but I get an error.

‘ssh’ is not recognized as an external coomand, operable program or batch file.
Info in TApplicationRemote::TApplicationRemote: an error occured during SSH connection
Error in TApplication::Open: TApplicationRemote for username@lxplus.cern.ch could not be instantiated.

What should I do to fix this error?

Kind regards,

4

Hi,

You must have cygwin installed and your path must contain the path to cygwin/bin in order to be able to use ssh from cygwin (or you can try to search on google for the minimum cygwin’s ssh installation on Windows)
You can also try to find a ssh client working on Windows…

Cheers,
Bertrand.

5

Dear Bertrand;

Thank you for your help. I solved my problem. It works great.

Kind regards.

6

You are welcome :smiley:

Regards,
Bertrand.