On Mon, 11 Jan 1999, Rene Brun wrote:
> > with root 2.20/06 I find that in
> >
> > void fcn( Int_t &npar, Double_t *gin, Double_t &f,
> > Double_t *par, Int_t iflag) {
> >
> > // my fit code
> >
> > }
> >
> > which is called by MINUIT through TMinuit the parameter iflag is not
> > passed correctly. Even calling fcn explicitly with
> >
> > ...
> > arglist[0]= 4;
> > gMinuit->mnexcm( "CALL", arglist, 1, ierflg );
> > ...
> >
> > I get nonsense (i.e something like iflag= 6585878) for iflag in fcn. This
> > is bad, because traditionally in MINUIT style fits one has if-blocks in
> > the fcn function which test the value of iflag to initialise, calculate
> > the fit function or do some final calculation after the fit is done. At
> > the moment, I have a workaround by using an extra constant fit parameter
> > to pass a value for iflag, but this is quite ugly.
> I cannot reproduce this problem.
> We provide a simple test program in $ROOTSYS/test/minexam.
> Could you put a print statement in the function fcnk0 of the example
> and tell me if you get what is expected. I have no problems with it.
Hm, the difference is that the minexam.cxx is compiled while mine is
interpreted. I reproduced my problem by modifying minexam.cxx such that it
can be loaded with ".L minexam.cxx". On printing "iflag" at the beginning
if fcnk0 I get:
iflag= 536751360 (dec/alpha cxx6)
iflag= -1073835196 (Linux)
The compiled versions work fine on both systems.
cheers, Stefan
PS: I found that cint doesn't like
const Int_t MXBIN= 50;
static Double_t thplu[MXBIN];
I had to change it to
static Double_t thplu[50];
but I don't understand why.
---Stefan Kluth---------------Lynen Fellow----------------|\--|\-------
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