Hi John,
I see two different scenarios:
1) Your fit is linear in the fit parameters .
So it takes 4 weeks to calculate the derivatives
of interest for estimating the Hessian matrix and
the
gradient . I see absolutely no way to store
the status half way and pick it up from there
without heavy hacking in the code .
2) The fit is non-linear in the parameters and it
takes
several iterations to get the objective's minimum.
In this case, all you need are the current
fit parameter values after each step . Minuit
does print these values out but I do not see at the
moment an implemented function to get them .
It is easy to pinpoint the place where they are
printed, so you could add some statements there.
Eddy
--- "Dr. John Krane" <jkrane@netzero.com> wrote:
> Hi everyone,
>
> I'm not sure I made my original desire clear. My
> fit takes anywhere
> from 1 week to 4 weeks to complete. That is a
> single "MINI" command. I
> would like to write the intermediate states to a
> file so I don't lose
> data completely if I overwhelm Windows on day 6 with
> a huge database
> operation while ROOT is working in the background.
>
> So my structure is basically
>
> TVirutalFitter *myminuit; //declared globally
> int main( blah ) {
> myminuit = TVirtualFitter::Fitter(0, ARRAYSIZE);
> myminuit->ExecuteCommand("MINI",arglist,0);
> }
> void func_fit::minimize(Int_t &npar, Double_t *grad,
> Double_t &mychi2,
> Double_t *params, Int_t
> iflag){
> // blah blah...compute "mychi2" based on "npar"
> values
> count++;
> if (fmod(count,10000)==0) myminuit->Write();
> }
>
> So, myminuit is *in the middle* of fitting when I
> try to write it to
> disk. In fact, it is in the middle of a call to my
> user-function when I
> try to write it to disk. I don't know if I can
> write successfully at
> this time, but it is what I must try to do. In this
> sense, putting
> gMinuit->Write() into tutorials/Ifit.C is not
> relevant because I do not
> intend to wait politely for Minuit to finish the fit
> before I try to
> write it to disk.
>
> Does anybody know if something about the guts of
> TVirtualFitter
> prohibits me from even trying to do this? Maybe I
> can edit
> TVirtualFitter in ROOT to put in a method that does
> a this->Write() or
> something, so it at least won't be in the middle of
> a function call when
> I try to write it.
>
> - John
>
> >>Program received signal SIGSEGV, Segmentation
> fault.
> >>[Switching to Thread 1091201184 (LWP 24100)]
> >>0x4025d8a2 in ROOT::TObject_IsA(void const*) ()
> from
> >>
> >>/bin/root/lib/libCore.so
> >>(gdb) where
> >>#0 0x4025d8a2 in ROOT::TObject_IsA(void const*)
> ()
> >>from
> >>/bin/root/lib/libCore.so
> >>#1 0x401619b4 in TClass::GetActualClass(void
> >>const*) const () from
> >>/bin/root/lib/libCore.so
> >>#2 0x400ec4ff in TBuffer::WriteObjectAny(void
> >>const*, TClass*) () from
> >>/bin/root/lib/libCore.so
> >>#3 0x4024f7cf in operator<<(TBuffer&, TObject
> >>const*) () from
> >>/bin/root/lib/libCore.so
> >>#4 0x40e9d933 in TMinuit::Streamer(TBuffer&) ()
> >>from
> >>/bin/root/lib/libMinuit.so
> >>#5 0x40101246 in TKey::TKey(TObject*, char
> const*,
> >>int) () from
> >>/bin/root/lib/libCore.so
> >>#6 0x4010e293 in TObject::Write(char const*, int,
> >>int) () from
> >>/bin/root/lib/libCore.so
> >>#7 0x0805297c in func_fit::minimize(int&,
> double*,
> >>double&, double*,
> >>int) (this=0x8059a20, npar=@0xbfffd4f4,
> >>grad=0xd6f56d0, mychi2=@0xbfffd620,
> >> params=0xd6ec0b0, iflag=4) at func_fit.cpp:395
> >>#8 0x080547d5 in dummy_func(int&, double*,
> double&,
> >>double*, int)
> >>(npar=@0xbfffd4f4, grad=0xd6f56d0,
> >>mychi2=@0xbfffd620, params=0xd6ec0b0,
> >>iflag=4)
> >> at fit_idx.cpp:46
> >>#9 0x40e8458d in TMinuit::Eval(int, double*,
> >>double&, double*, int) ()
> >>from /bin/root/lib/libMinuit.so
> >>#10 0x40e8d827 in TMinuit::mnhess() () from
> >>/bin/root/lib/libMinuit.so
> >>#11 0x40e914b7 in TMinuit::mnmigr() () from
> >>/bin/root/lib/libMinuit.so
> >>#12 0x40e8a21a in TMinuit::mnexcm(char const*,
> >>double*, int, int&) ()
> >>from /bin/root/lib/libMinuit.so
> >>#13 0x40e8020f in TFitter::ExecuteCommand(char
> >>const*, double*, int) ()
> >>from /bin/root/lib/libMinuit.so
> >>#14 0x08055296 in main (argc=2, argv=0xbfffe874)
> at
> >>fit_idx.cpp:140
> >>#15 0x420156a4 in __libc_start_main () from
> >>/lib/tls/libc.so.6
> >>
> >>
> >>
> >>
> >
> >
> >
> >
> >
>
> --
>
> Dr. John Krane
> jkrane@netzero.com
>
>
This archive was generated by hypermail 2b29 : Sun Jan 02 2005 - 05:50:07 MET