Dear All
I am fitting a line shape using TMinuit, MINOS, however, the results are always “STATUS=PROBLEMS” or “STATUS=FAILURE”.
I do not know how to optimize it.
Here is my options in code:
TMinuit *ptMinuit = new TMinuit(iNum);
ptMinuit->SetPrintLevel();
ptMinuit->SetFCN(calc_chi_square);
ptMinuit->SetMaxIterations(1000);
Double_t arglist[10];
Int_t ierflg = 0;
arglist[0] = 1;
ptMinuit->mnexcm("SET ERR", arglist ,1,ierflg);
arglist[0] = 2;
ptMinuit->mnexcm("SET STR", arglist ,1,ierflg);
for(int i=0; i<ipar; i++){
parmintem[i]=vstart[i];
ptMinuit->mnparm(i, pars_name[i], vstart[i], step[i], vstart_low[i], vstart_high[i], ierflg);
}
arglist[0] = 5000;
arglist[1] = 1.6;
ptMinuit->mnexcm("SIMPLEX", arglist ,ipar,ierflg);
ptMinuit->mnexcm("MIGRAD", arglist ,ipar,ierflg);
ptMinuit->mnexcm("MIGRAD", arglist ,ipar,ierflg);
ptMinuit->mnexcm("MINOS", arglist ,ipar,ierflg);
And here is the details:
FCN=16.0683 FROM MINOS STATUS=NEW MINIMU 227 CALLS 30345902 TOTAL
EDM= unknown STRATEGY= 2 NO ERROR MATRIX
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 a0 -2.70737e+00 4.41469e-01
2 a1 9.50336e-01 4.67776e-01
3 a2 -5.99460e+00 3.77415e+00
4 a3 8.19141e-01 1.32770e+00
5 a4 2.98390e+00 3.56443e+00
6 a5 -5.06823e-01 8.45144e-01
NEW MINIMUM FOUND. GO BACK TO MINIMIZATION STEP.
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MINUIT WARNING IN HESSE
============== Negative diagonal element 3 in Error Matrix
MINUIT WARNING IN HESSE
============== Negative diagonal element 5 in Error Matrix
MINUIT WARNING IN HESSE
============== 11.6231 added to diagonal of error matrix
EIGENVALUES OF SECOND-DERIVATIVE MATRIX:
-1.4213e+00 -3.6672e-02 1.7827e-02 1.5054e-01 9.9964e-01 6.2899e+00
MINUIT WARNING IN HESSE
============== MATRIX FORCED POS-DEF BY ADDING 1.427548 TO DIAGONAL.
EIGENVALUES OF SECOND-DERIVATIVE MATRIX:
-5.2637e-03 1.7040e-05 1.9500e-02 6.2492e-01 1.0662e+00 4.2946e+00
MINUIT WARNING IN MIGRAD
============== MATRIX FORCED POS-DEF BY ADDING 0.009558 TO DIAGONAL.
MIGRAD MINIMIZATION HAS CONVERGED.
MIGRAD WILL VERIFY CONVERGENCE AND ERROR MATRIX.
FCN=3.05887 FROM MIGRAD STATUS=CONVERGED 4843 CALLS 30350745 TOTAL
EDM=3.12499e-05 STRATEGY= 2 ERROR MATRIX ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 a0 -5.44166e+00 6.20311e+00 2.76801e-05 1.56653e-02
2 a1 9.99999e-01 3.92643e-07 1.46198e-10 -1.73244e+03
3 a2 -3.15107e+00 7.98764e-04 1.47401e-06 -1.76736e+01
4 a3 4.12862e-03 3.68619e-04 2.17488e-08 2.56198e+01
5 a4 5.14168e-02 4.40022e+00 1.77173e-05 -1.96943e-02
6 a5 -3.25259e-01 1.14480e-02 8.77797e-07 4.70225e-01
CALL LIMIT EXCEEDED IN MIGRAD.
MINUIT WARNING IN HESSE
============== Negative diagonal element 2 in Error Matrix
MINUIT WARNING IN HESSE
============== Negative diagonal element 3 in Error Matrix
MINUIT WARNING IN HESSE
============== Negative diagonal element 5 in Error Matrix
MINUIT WARNING IN HESSE
============== 9.21912e+09 added to diagonal of error matrix
EIGENVALUES OF SECOND-DERIVATIVE MATRIX:
-1.7956e+04 1.0000e+00 1.0000e+00 1.0829e+00 1.7957e+04
MINUIT WARNING IN HESSE
============== MATRIX FORCED POS-DEF BY ADDING 17973.511877 TO DIAGONAL.
MINUIT WARNING IN MIGRAD
============== Negative diagonal element 3 in Error Matrix
MINUIT WARNING IN MIGRAD
============== 1.00002 added to diagonal of error matrix
MINUIT WARNING IN HESSE
============== Negative diagonal element 2 in Error Matrix
MINUIT WARNING IN HESSE
============== Negative diagonal element 3 in Error Matrix
MINUIT WARNING IN HESSE
============== Negative diagonal element 4 in Error Matrix
MINUIT WARNING IN HESSE
============== 1.59089e+06 added to diagonal of error matrix
EIGENVALUES OF SECOND-DERIVATIVE MATRIX:
-2.3125e+03 7.6667e-01 9.9065e-01 1.0000e+00 2.3147e+03
MINUIT WARNING IN HESSE
============== MATRIX FORCED POS-DEF BY ADDING 2314.787661 TO DIAGONAL.
FCN=3.05887 FROM MINOS STATUS=FAILURE 5711 CALLS 30356456 TOTAL
EDM=3.12499e-05 STRATEGY= 2 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 a0 -5.44166e+00 6.20311e+00
2 a1 9.99999e-01 3.92643e-07
3 a2 -3.15107e+00 7.98764e-04
4 a3 4.12862e-03 3.68619e-04
5 a4 5.14168e-02 4.40022e+00
6 a5 -3.25259e-01 1.14480e-02