Re: [ROOTDEV] problem with TF1 (fwd)

When you use the interpreter and call TF1::EvalPar you must specify the address of the parameters array.
The doc says:

   // WARNING. In case of an interpreted function (fType=2), it is the
   // user's responsability to initialize the parameters via InitArgs
   // before calling this function.
   // InitArgs should be called at least once to specify the addresses
   // of the arguments x and params.
   // InitArgs should be called everytime these addresses change.

I have modified your code such that it works with or without the interpreter. (see atatchment)

Rene Brun

Alessio Mangiarotti wrote:
> Dear Rene,
>
> thank you very much for your patience, but this, unfortunately, did
> not help me. I changed the code as you suggested and I still get a
> segmentation violation. I tried this also on root 5.22/00d on SL 4.8
> with gcc 4.1.2.
>
> This is the output of the crush:
> *** Break *** segmentation violation
> Using host libthread_db library "/lib64/tls/libthread_db.so.1".
> Attaching to program: /proc/13977/exe, process 13977
> [Thread debugging using libthread_db enabled]
> [New Thread 182923994176 (LWP 13977)]
> 0x000000396d590104 in waitpid () from /lib64/tls/libc.so.6
> #1 0x000000396d539aff in do_system () from /lib64/tls/libc.so.6
> #2 0x0000002a957e0390 in TUnixSystem::StackTrace () from
> /usr/local/root/root/lib/libCore.so.5.22
> #3 0x0000002a957de0e3 in TUnixSystem::DispatchSignals () from
> /usr/local/root/root/lib/libCore.so.5.22
> #4 <signal handler called>
> #5 0x0000002a960968ae in G__LD_P10_double () from
> /usr/local/root/root/lib/libCint.so.5.22
> #6 0x0000002a95f99cd0 in G__exec_asm () from
> /usr/local/root/root/lib/libCint.so.5.22
> #7 0x0000002a95fa01fa in G__exec_bytecode () from
> /usr/local/root/root/lib/libCint.so.5.22
> #8 0x0000002a9601f836 in G__interpret_func () from
> /usr/local/root/root/lib/libCint.so.5.22
> #9 0x0000002a95fbd3aa in Cint::G__CallFunc::ExecInterpretedFunc ()
> from /usr/local/root/root/lib/libCint.so.5.22
> #10 0x0000002a95fbd596 in Cint::G__CallFunc::Execute () from
> /usr/local/root/root/lib/libCint.so.5.22
> #11 0x0000002a957c4951 in TCint::CallFunc_ExecDouble () from
> /usr/local/root/root/lib/libCore.so.5.22
> #12 0x0000002a957b2294 in TMethodCall::Execute () from
> /usr/local/root/root/lib/libCore.so.5.22
> #13 0x0000002a983ec3c1 in TF1::EvalPar () from
> /usr/local/root/root/lib/libHist.so
> #14 0x0000002a985f51fa in G__G__Hist_199_0_36 () from
> /usr/local/root/root/lib/libHist.so
> #15 0x0000002a95f8658f in Cint::G__ExceptionWrapper () from
> /usr/local/root/root/lib/libCint.so.5.22
> #16 0x0000002a9604c650 in G__execute_call () from
> /usr/local/root/root/lib/libCint.so.5.22
> #17 0x0000002a9604d669 in G__call_cppfunc () from
> /usr/local/root/root/lib/libCint.so.5.22
> #18 0x0000002a960203ab in G__interpret_func () from
> /usr/local/root/root/lib/libCint.so.5.22
> #19 0x0000002a9600f1a6 in G__getfunction () from
> /usr/local/root/root/lib/libCint.so.5.22
> #20 0x0000002a9611eb69 in G__getstructmem () from
> /usr/local/root/root/lib/libCint.so.5.22
> #21 0x0000002a9611493b in G__getvariable () from
> /usr/local/root/root/lib/libCint.so.5.22
> #22 0x0000002a95fde31a in G__getitem () from
> /usr/local/root/root/lib/libCint.so.5.22
> #23 0x0000002a95fe90d2 in G__getexpr () from
> /usr/local/root/root/lib/libCint.so.5.22
> #24 0x0000002a95feb241 in G__getexpr () from
> /usr/local/root/root/lib/libCint.so.5.22
> #25 0x0000002a9607a45c in G__exec_statement () from
> /usr/local/root/root/lib/libCint.so.5.22
> #26 0x0000002a960220b4 in G__interpret_func () from
> /usr/local/root/root/lib/libCint.so.5.22
> #27 0x0000002a9600d3b0 in G__getfunction () from
> /usr/local/root/root/lib/libCint.so.5.22
> #28 0x0000002a95fde47d in G__getitem () from
> /usr/local/root/root/lib/libCint.so.5.22
> #29 0x0000002a95fe90d2 in G__getexpr () from
> /usr/local/root/root/lib/libCint.so.5.22
> #30 0x0000002a96082319 in G__exec_statement () from
> /usr/local/root/root/lib/libCint.so.5.22
> #31 0x0000002a95fc7514 in G__exec_tempfile_core () from
> /usr/local/root/root/lib/libCint.so.5.22
> #32 0x0000002a95fc77ee in G__exec_tempfile_fp () from
> /usr/local/root/root/lib/libCint.so.5.22
> #33 0x0000002a9608d505 in G__process_cmd () from
> /usr/local/root/root/lib/libCint.so.5.22
> #34 0x0000002a957c8261 in TCint::ProcessLine () from
> /usr/local/root/root/lib/libCore.so.5.22
> #35 0x0000002a956e4305 in TApplication::ProcessLine () from
> /usr/local/root/root/lib/libCore.so.5.22
> #36 0x0000002a96f9cb78 in TRint::HandleTermInput () from
> /usr/local/root/root/lib/libRint.so.5.22
> #37 0x0000002a96f9ac77 in TTermInputHandler::Notify () from
> /usr/local/root/root/lib/libRint.so.5.22
> #38 0x0000002a96f9d4fd in TTermInputHandler::ReadNotify () from
> /usr/local/root/root/lib/libRint.so.5.22
> #39 0x0000002a957ddd05 in TUnixSystem::CheckDescriptors () from
> /usr/local/root/root/lib/libCore.so.5.22
> #40 0x0000002a957de25b in TUnixSystem::DispatchOneEvent () from
> /usr/local/root/root/lib/libCore.so.5.22
> #41 0x0000002a9574ab55 in TSystem::InnerLoop () from
> /usr/local/root/root/lib/libCore.so.5.22
> #42 0x0000002a9574dcb1 in TSystem::Run () from
> /usr/local/root/root/lib/libCore.so.5.22
> #43 0x0000002a956e28df in TApplication::Run () from
> /usr/local/root/root/lib/libCore.so.5.22
> #44 0x0000002a96f9d0b4 in TRint::Run () from
> /usr/local/root/root/lib/libRint.so.5.22
> #45 0x000000000040109d in main ()
>
>
> Maybe I am doing something trivially stupid, but I can not see it.
>
> My problem of sending messages to the roottalk list has been solved
> (thanks to Fons Rademakers), so I think it is more appropriate to
> switch these emails to the general roottalk mailing list.
>
> Alessio.
>
>
> On Mon, 23 Nov 2009, Rene Brun wrote:
>
>> You have an error in your C++ code. Replace your function by:
>>
>> Double_t myfunction(Double_t *x, Double_t *par)
>> {
>> Float_t xx =x[0];
>> Double_t f;
>> if (xx!=0.) {
>> f = TMath::Abs(par[0]*TMath::Sin(par[1]*xx)/xx);
>> } else {
>> f =0.;
>> }
>> return f;
>> }
>>
>>
>> Rene
>>
>> Alessio Mangiarotti wrote:
>>> Dear root developers,
>>>
>>> I am sorry to generate spam on this other address, but my messages
>>> can not get to the roottalk list (I am a subscribed user). Am I
>>> doing something wrong or it is just a miss-configuration of some
>>> filter?
>>>
>>> Regards,
>>> Alessio Mangiarotti.
>>>
>>>
>>>
>>> ---------- Forwarded message ----------
>>> Date: Fri, 20 Nov 2009 03:11:40 +0000 (WET)
>>> From: Alessio Mangiarotti <alessio_at_lipc.fis.uc.pt>
>>> To: roottalk_at_root.cern.ch
>>> Cc: Alessio Mangiarotti <alessio_at_lipc.fis.uc.pt>
>>> Subject: problem with TF1 (fwd)
>>>
>>>
>>> It seems it did not get trough, for some reasons. I attach here the
>>> gdb output as requested on the site.
>>>
>>> I hope it gets trough now,
>>> Regards,
>>> Alessio Mangiarotti.
>>>
>>>
>>> ---------- Forwarded message ----------
>>> Date: Thu, 19 Nov 2009 01:33:55 +0000 (WET)
>>> From: Alessio Mangiarotti <alessio_at_lipc.fis.uc.pt>
>>> To: roottalk_at_root.cern.ch
>>> Cc: Alessio Mangiarotti <alessio_at_lipc.fis.uc.pt>
>>> Subject: problem with TF1
>>>
>>> Dear rooters,
>>>
>>> I am experiencing a strange problem with TF1. In essence, I would
>>> like to calculate a function for given values of the argument and
>>> the parameters. I would also like to plot the function. However when
>>> I use ->EvalPar() on a c function I defined, root crashes. I
>>> reproduced the problem in a much simpler macro I attach here. If the
>>> function is defined with an in line expression in TF1 root does not
>>> crashes. I am using root version 5.24/00b on ubuntu 6.10 (gcc
>>> 4.4.1-4). Maybe I am doing something stupid, but I can not see it!
>>>
>>> To reproduce the problem just type:
>>> .L tf1_problem.C
>>> tf1_problem();
>>>
>>>
>>> I would appreciate any help.
>>> Best Regards,
>>> Alessio Mangiarotti.
>>
>>
>