Hi Perfetto,
You should replace your line
> Double_t delta_egamma(TLorentzVector x,TLorentzVector y)
with
> Double_t delta_egamma(TLorentzVector& x,TLorentzVector& y)
and all will be fine.
Best regards,
Stanislav.
On Wed, 25 Sep 2002, Perfetto Francesco wrote:
> Hi ROOTers,
> I am sorry if this question is very too trivial, but I don't know where
> mistake.
> The problem is that, when call the my function "delta_egamma" in my
> program ,root tell me :
>
> root [0] .L ana_dali_mc.C
> root [1] ana_dali_mc mio
> root [2] mio.Loop()
> Error: Illegal Assignment to an undeclared symbol TLorentzVectorx
> FILE:ana_dali_mc.C LINE:304
> *** Interpreter error recovered ***
>
> My program is:
>
> #define ana_dali_mc_cxx
> #include "ana_dali_mc.h"
>
> void ana_dali_mc::Loop()
> {
>
> if (!TClassTable::GetDict("Physics")) {
> gSystem.Load("$ROOTSYS/lib/libPhysics.so");
> }
> ...
> Double_t pluto;
> TLorentzVector p4datetasys_pim,p4datetasys_pip,p4datetasys_piz;
> TTree *tmc = new TTree("tmc","Tree for montecarlo");
>
> for (Int_t jentry=0; jentry<nentries;jentry++)
> { ...
> pluto = delta_egamma(p4datetasys_pip,p4datetasys_pim);
> tmc ->Fill();
> }
> }
>
> Double_t delta_egamma(TLorentzVector x,TLorentzVector y)
> {
> Double_t delta;
> TLorentzVector pippo;
>
> pippo = x;
> mimmie= y;
> ...
> delta = pippo.Mag2();
>
> return delta;
> }
>
> Someone can tell me how can I do that ?(where is my mistake ? )
>
> Regards
> Francesco.
>
>
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