Compiling a RooFit User Pdf with g++

Roofit and RooStats
1

Hi all,

I have created a RooAbsPdf via the class factory method using the example shown at hep.by/root/tutorials/roofit … ory.C.html.

I can compile the source files it produces with ROOT via

but with g++ command,

I receive the error,

usr/lib/../lib64/crt1.o: In function `_start': (.text+0x20): undefined reference to `main' /tmp/dvoong/ccty6oh4.o: In function `__static_initialization_and_destruction_0(int, int)': MyPdfV1.cxx:(.text+0x2da): undefined reference to `ROOT::GenerateInitInstance(MyPdfV1 const*)' /tmp/dvoong/ccty6oh4.o: In function `MyPdfV1::IsA() const': MyPdfV1.cxx:(.text._ZNK7MyPdfV13IsAEv[MyPdfV1::IsA() const]+0x13): undefined reference to `MyPdfV1::Class()' /tmp/dvoong/ccty6oh4.o:(.rodata._ZTV7MyPdfV1[vtable for MyPdfV1]+0x1d0): undefined reference to `MyPdfV1::ShowMembers(TMemberInspector&)' /tmp/dvoong/ccty6oh4.o:(.rodata._ZTV7MyPdfV1[vtable for MyPdfV1]+0x1d8): undefined reference to `MyPdfV1::Streamer(TBuffer&)' /tmp/dvoong/ccty6oh4.o:(.rodata._ZTV7MyPdfV1[vtable for MyPdfV1]+0x630): undefined reference to `non-virtual thunk to MyPdfV1::ShowMembers(TMemberInspector&)' /tmp/dvoong/ccty6oh4.o:(.rodata._ZTV7MyPdfV1[vtable for MyPdfV1]+0x638): undefined reference to `non-virtual thunk to MyPdfV1::Streamer(TBuffer&)' collect2: ld returned 1 exit status

I’ve tried to include various headers and libraries to the compiler but with no avail. Any idea what the issue is?

I am using,

/afs/cern.ch/sw/lcg/app/releases/ROOT/5.34.07a/x86_64-slc5-gcc46-opt/root/

and

gcc version 4.6.3 (GCC)

Thanks

2

Hi,

I like to do the same for my custom PDF. Did anyone ever got an answer to this question?

Wing

3

Hi Wing,

I eventually found out how to do it. For a user class called MyRooPdf,

  1. Generate the RooPdf’s using the RooClassFactory. This generates two files, MyRooPdf.h and MyRooPdf.cxx
  2. Then create a Linkdef.h file which is required by ROOT to generate a dictionary for the class
  3. Use the rootcint command to generate the dictionary
  4. Create a shared library using your class and its dictionary

I’ve attached some files which hopefully should have everything you need, I made these a while ago, hopefully they still work with the newer versions of ROOT.
Makefile.txt (724 Bytes)
MyRooPdfDict.cxx (65.1 KB)
MyRooPdfDict.h (6.57 KB)
MyRooPdf.cxx (1.26 KB)
MyRooPdf.h (1.1 KB)
LinkDef.h (59 Bytes)

4

Thanks David, I am going to try it today.

5

Hi David,

Your method of creating a shared library worked well until I try to include the class into my code. The program compiles but when I run it it gives this error.

error while loading shared libraries: libRooSigCoeff.so.1: cannot open shared object file: No such file or directory

I tried making new sym links and even copies of the library files. It’s probably something I am doing work in my main makefile so I will keep trying to debug it. Let me know if you already ran into the same problem and know a fix for it already.

Thanks,

6

Hi Wing,

I think I had the same problem but didn’t solve it. I suspect it might be an issue to do with where the file is located, maybe it needs to be copied into a default location where the compiler looks for it or having some flag telling the compiler where to look?

The way I used my own user class was to load it into CINT, in pyROOT the command to do that is,

import ROOT
ROOT.gSystem.Load("MyRooPdf.so")

x = MyRooPdf(<arguments go here>)

there should be some equivalent command in the CINT shell. Hope that helps.

David

7

Hi David,

I solve the problem by adding my custom library path to the g++ line using this -Wl,-rpath option.

g++ $(OBJ) -o $@ $(FLAGS) $(INCS) $(LIBS) -Wl,-rpath=$(shell pwd)/…/Models/ …/Models/libRooSignalPDF.so

That worked out fine, but when I add a 2nd PDF for example

g++ $(OBJ) -o $@ $(FLAGS) $(INCS) $(LIBS) -Wl,-rpath=$(shell pwd)/…/Models/ …/Models/libRooSignalPDF.so …/Models/libRooBackgroundPDF.so

Where the Signal and Background PDF are basically made the same way. I get this error

*** glibc detected *** double free or corruption (fasttop):

I think there’s probably something wrong in the way I am linking multiple libs to my program.

8

nt