[ROOT] problem plotting function

From: BORRAS David (borras@clermont.in2p3.fr)
Date: Thu Oct 21 2004 - 23:16:57 MEST

Hi Rootters,

I have written a code in FML_Minuit where i minimize a unbinned likelihood
method. In this code i define a class MyFunction where i implement the
function to be used in fitter. This function is the convolution between
exponential and gaussian function. To do this i use functions from CLHEP
package (AnalyticConvolution.hh).
I would like only plot this function convolution and i write some "root
line" for that.
here is :

// Here is the name of my class
MyFunction f;

....some treatments

//To run root
TApplication theApp(...)
// create the canvas for plot
TCanvas *vc ... 

and here is my problem :
TF1 *f1 = new TF1("fct","f",xmin,xmax);

The code compile fine, but when i execute it, i have the following message
"bad numerical expression "f".The function fct/f has 0 parameters instead
of 1."

The canvas appears fine and i only have a line in it.
Is my problem come from the fact that my function is a member of my
defined class or i make something wrong in the code ?

Cheers, David 
*  David Borras                                 *
*  PhD Student                                  *
*  Laboratoire de Physique Corpusculaire (LPC)  *
*  IN2P3/CNRS                                   *
*  Universite Blaise Pascal                     *
*  24 avenue des Landais                        *
*  63177 Aubiere Cedex                          *
*                                               *
*  tel : 04 73 40 72 77 (work)                  *
*  mail: borras@clermont.in2p3.fr               *

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