Does PROOF support friend trees?

I have a few trees residing in separate files, and use “AddFriend” to associate them together. Something like:

[code]TChain chain = new TChain(“tree_main”);

TChain chain_elec = new TChain(“tree_elec”);

TChain chain_muon = new TChain(“tree_muon”);



The above works under ROOT, but not under PROOF. Under PROOF-Lite I got error:

[quote]TProofProgressStatus:: Ents:(0,0), Bytes:0, Calls:0, Learn:0 s, Proc:(0,0) s, CPU:0 s
14:52:09 4011 Wrk-0.0 | Info in TProofServLite::GetNextPacket: cacheSize: -1, learnent: 100
14:52:09 4011 Wrk-0.0 | Error in TClass::New: cannot create object of class TPair
14:52:09 4011 Wrk-0.0 | Error in TMessage::ReadObject: could not create object of class TPair
14:52:09 4011 Wrk-0.0 | Error in TExMap::Remove: key 16777216 not found at 155
14:52:09 4011 Wrk-0.0 | Warning in TMessage::CheckObject: reference to object of unavailable class TObject, offset=16777216 pointer will be 0
14:52:09 4011 Wrk-0.0 | Error in TMessage::CheckByteCount: object of class TList read too few bytes: 37 instead of 61

Has PROOF already supported friend tree? If yes, any idea on why my job failed? If not. will it be supported soon?



Dear Shuwei,

Support for TTree friends was introduced in PROOF at experimental level a long time ago and never really validated.
I will have a closer look and try to understand what is the status.
If a change/fix is needed I will make sure that it appears in the next patch release to 5.26/00 .

G. Ganis