Dear Experts,
I am doing unbinned maximum likelihood fitting with RooSimultaneous (2 categories), which gives me the following results.
FCN=-76742 FROM MIGRAD STATUS=INITIATE 12 CALLS 13 TOTAL
FIRST CALL TO USER FUNCTION AT NEW START POINT, WITH IFLAG=4.
START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT. 1.00e-03
EDM= unknown STRATEGY= 1 NO ERROR MATRIX
EXT PARAMETER CURRENT GUESS STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 fB 1.00000e-01 5.00000e-02 1.72186e-01 -2.89222e+02
2 fsig_ff 1.00000e-01 5.00000e-02 1.72186e-01 2.22965e+03
3 fsig_fs 1.00000e-01 5.00000e-02 1.72186e-01 2.11380e+03
ERR DEF= 0.5
MIGRAD MINIMIZATION HAS CONVERGED.
MIGRAD WILL VERIFY CONVERGENCE AND ERROR MATRIX.
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-77407.8 FROM MIGRAD STATUS=CONVERGED 124 CALLS 125 TOTAL
EDM=2.53449e-06 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 fB 3.36934e-01 4.44038e-02 1.77798e-02 -4.30100e-03
2 fsig_ff 2.90215e-02 2.72814e-03 3.12182e-03 9.38526e-02
3 fsig_fs 1.59796e-02 2.85037e-03 4.30456e-03 -5.30582e-04
But when I try to plot NLL for one category then this value changes and gives the following…
START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT. 1.00e-03
FCN=-122430 FROM MIGRAD STATUS=INITIATE 8 CALLS 9 TOTAL
EDM= unknown STRATEGY= 1 NO ERROR MATRIX
EXT PARAMETER CURRENT GUESS STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 fB 3.36934e-01 4.43149e-02 9.39438e-02 2.98954e+03
2 fsig_ff 2.90215e-02 2.72715e-03 1.62636e-02 -2.10721e+04
ERR DEF= 0.5
MIGRAD MINIMIZATION HAS CONVERGED.
MIGRAD WILL VERIFY CONVERGENCE AND ERROR MATRIX.
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-136092 FROM MIGRAD STATUS=CONVERGED 42 CALLS 43 TOTAL
EDM=6.64737e-05 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 fB 1.90733e-09 3.58337e-05 3.05037e-03** at limit **
2 fsig_ff 3.25133e-01 2.61684e-03 1.42321e-03 -6.50984e-01
I don’t understand why this situation occurs here, please share your opinions.
For a complete fitting overview. I have attached the full log info here. Output_log.txt (26.8 KB)