gMinuit problem ..

From: Arthur E. Snyder <snyder_at_slac.stanford.edu>
Date: Fri, 27 Feb 2009 17:42:05 -0800

Rene et al.,

We are seeing strange behavior with gMinuit. It seems to come and go. I expect it to be there after I do it fit.

An example:

I have a histogram (it doesn't matter what it is).

root [26] h->Fit("pol4")
Fitting results:
Parameters:

NO.             VALUE           ERROR
0       2.625170e+03    1.191186e+02
1       -1.565262e+04   1.055977e+03
2       3.861477e+04    3.327115e+03
3       -4.315887e+04   4.446220e+03
4       1.804345e+04    2.140152e+03

(Int_t)0
root [27] gMinuit
(class TMinuit*)0x0
root [28]

-->gMinuit is MIA

root [28] h->Fit("gaus")
  FCN=687.968 FROM MIGRAD STATUS=CONVERGED 3927 CALLS 3928 TOTAL

                      EDM=5.19353e-06    STRATEGY= 1      ERR MATRIX NOT 
POS-DEF
   EXT PARAMETER                APPROXIMATE        STEP         FIRST
   NO.   NAME      VALUE            ERROR          SIZE      DERIVATIVE
    1  Constant     1.93812e+09   1.54608e+08   9.24169e+02   2.24749e-10
    2  Mean        -8.98813e+00   2.37909e-02   2.18708e-05   1.46725e+00
    3  Sigma        1.67356e+00   3.02321e-02   2.53915e-03** at limit **

(Int_t)0
root [29] gMinuit
(class TMinuit*)0x9486650

-->gMinuit is there!

In a more complex sitution where we construct a simple TF1 in a macro, gMinuit is sometimes there and sometimes not -- seemingly w/o reason --

-Art S.

A.E. Snyder, Group EC                        \!c*p?/
SLAC Mail Stop #95                          ((.   .))
Box 4349                                        |
Stanford, Ca, USA, 94309                      '\|/`
e-mail:snyder_at_slac.stanford.edu                 o
phone:650-926-2701                              _
http://www.slac.stanford.edu/~snyder          BaBar
FAX:650-926-2657                          Collaboration

Received on Sat Feb 28 2009 - 02:42:13 CET