MINOS failing to calculate the +ve and -ve error for free parameters during extended likelihood fit

nsahoo · July 20, 2016, 7:06pm

Hi all,

I’m using MINOS in extended likelihood fit in my fitter. The MINOS is
showing “PROBLEMS” status in this case. If you look at the print out
message below, MIGRAD and HESSE returns the error values successfully
whereas MINOS is unable to calculate the asymmetric errors for the free
parameters (AFB,FL). It’s unable to find +ve and -ve error in case of those
parameters (have a look on the printout message towards end). Could you
please tell me how to fix this problem ?

cheers,
Niladri

[nsahoo@lxplus047 plugins]$ ./fit angular2D
./…/…/…/…/…/BuToKstarMuMu/ntp/sel/v3p3/mc/sig/“sel_BToKstarMuMu_SCN_8TeV_*.root”

RooFit v3.60 – Developed by Wouter Verkerke and David Kirkby
Copyright © 2000-2013 NIKHEF, University of California &
Stanford University
All rights reserved, please read
roofit.sourceforge.net/license.txt

INFO : ScaleFactor for input data is 1.000
INFO : Plots will be stored to ./plots
INFO : Datacards will be stored to .
INFO : Workspaces will be stored to .
Do you want to redo fitting? [y/n]:y
[#1] INFO:Eval – RooAbsReal::attachToTree(Triggers) TTree Int_t branch
Triggers will be converted to double precision

[#1] INFO:Eval – RooTreeDataStore::loadValues(data) Ignored 116260116 out
of range events
INFO : Start MIGRAD loop

** 13 **MIGRAD 1500 1

FIRST CALL TO USER FUNCTION AT NEW START POINT, WITH IFLAG=4.
[#1] INFO:NumericIntegration –
RooRealIntegral::init(f_sigA_Int[CosThetaK,CosThetaL]) using numeric
integrator RooAdaptiveIntegratorND to calculate Int(CosThetaL,CosThetaK)
INFO: In dommap
(/mnt/build/jenkins/workspace/root-release-5.34/BUILDTYPE/Release/COMPILER/native/LABEL/slc6/sources/root_v5.34.36/root/roofit/roofitcore/src/BidirMMapPipe.cxx,
line 422): anonymous mmapping works, excellent!
[#1] INFO:Eval – RooAbsTestStatistic::initMPMode: started 4 remote server
process.
START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT.
1.00e-03
[#1] INFO:NumericIntegration –
RooRealIntegral::init(f_sigA_Int[CosThetaK,CosThetaL]) using numeric
integrator RooAdaptiveIntegratorND to calculate Int(CosThetaL,CosThetaK)
[#1] INFO:NumericIntegration –
RooRealIntegral::init(f_sigA_Int[CosThetaK,CosThetaL]) using numeric
integrator RooAdaptiveIntegratorND to calculate Int(CosThetaL,CosThetaK)
[#1] INFO:NumericIntegration –
RooRealIntegral::init(f_sigA_Int[CosThetaK,CosThetaL]) using numeric
integrator RooAdaptiveIntegratorND to calculate Int(CosThetaL,CosThetaK)
[#1] INFO:NumericIntegration –
RooRealIntegral::init(f_sigA_Int[CosThetaK,CosThetaL]) using numeric
integrator RooAdaptiveIntegratorND to calculate Int(CosThetaL,CosThetaK)
FCN=-587687 FROM MIGRAD STATUS=INITIATE 16 CALLS 17
TOTAL
EDM= unknown STRATEGY= 1 NO ERROR MATRIX

EXT PARAMETER CURRENT GUESS STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 9.00000e-01 2.00000e+00 2.02225e-01 3.13329e+03
2 fl 6.00000e-01 2.00000e+00 2.01742e-01 -1.09573e+04
3 nsig 1.00000e+04 4.95000e+03 5.15068e-03 -6.24207e+06
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-669400 FROM HESSE STATUS=OK 20 CALLS 155
TOTAL
EDM=0.09327 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.99477e-01 1.76087e-02 9.06734e-04 3.04125e+02
2 fl 7.27783e-01 1.29569e-02 7.44581e-04 -4.38549e+02
3 nsig 7.26513e+04 2.69463e+02 5.65385e-05 -3.06335e+03
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
MIGRAD TERMINATED WITHOUT CONVERGENCE.
FCN=-669400 FROM MIGRAD STATUS=FAILED 197 CALLS 198
TOTAL
EDM=1.522 STRATEGY= 1 ERROR MATRIX UNCERTAINTY
8.2 per cent
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.98023e-01 1.53400e-02 0.00000e+00 -1.11301e+03
2 fl 7.30438e-01 9.04278e-03 0.00000e+00 1.65755e+03
3 nsig 7.27925e+04 2.44647e+02 -0.00000e+00 2.16632e+03
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
2.353e-04 1.384e-04 1.367e+00
1.384e-04 8.177e-05 7.998e-01
1.367e+00 7.998e-01 5.985e+04
ERR MATRIX APPROXIMATE
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.99786 1.000 0.998 0.364
2 0.99786 0.998 1.000 0.362
3 0.36522 0.364 0.362 1.000
ERR MATRIX APPROXIMATE
INFO : MIGRAD return code=4

** 18 **MIGRAD 1500 1

START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT.
1.00e-03
FCN=-669400 FROM MIGRAD STATUS=INITIATE 14 CALLS 212
TOTAL
EDM=0.0215258 STRATEGY= 1 ERROR MATRIX UNCERTAINTY
8.2 per cent
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.98023e-01 1.53400e-02 0.00000e+00 -2.03612e+02
2 fl 7.30438e-01 9.04278e-03 0.00000e+00 2.99521e+02
3 nsig 7.27925e+04 2.44647e+02 -0.00000e+00 2.16632e+03
ERR DEF= 0.5
MINUIT WARNING IN MIGRAD
============== Negative diagonal element 1 in Error Matrix
MINUIT WARNING IN MIGRAD
============== Negative diagonal element 2 in Error Matrix
MINUIT WARNING IN MIGRAD
============== 1 added to diagonal of error matrix
MIGRAD FAILS TO FIND IMPROVEMENT
EIGENVALUES OF SECOND-DERIVATIVE MATRIX:
-1.4152e+01 1.0000e+00 1.6152e+01
MINUIT WARNING IN HESSE
============== MATRIX FORCED POS-DEF BY ADDING 14.167810 TO DIAGONAL.
FCN=-669400 FROM HESSE STATUS=NOT POSDEF 18 CALLS 258
TOTAL
EDM=9.58376 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.97351e-01 1.71110e-01 1.88762e-04 2.69147e+02
2 fl 7.30032e-01 7.92178e-03 1.33868e-04 -2.97158e+02
3 nsig 7.27273e+04 6.92432e+01 5.65682e-05 -2.48596e+02
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
MIGRAD TERMINATED WITHOUT CONVERGENCE.
FCN=-669400 FROM MIGRAD STATUS=FAILED 94 CALLS 292
TOTAL
EDM=534.681 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.95020e-01 4.97679e-03 0.00000e+00 -2.91751e+03
2 fl 7.29924e-01 5.59424e-04 0.00000e+00 2.18309e+04
3 nsig 7.27273e+04 6.92432e+01 0.00000e+00 -2.49489e+02
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
2.477e-05 2.513e-06 -1.369e-05
2.513e-06 3.130e-07 -6.327e-07
-1.369e-05 -6.327e-07 4.795e+03
ERR MATRIX NOT POS-DEF
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.90255 1.000 0.903 -0.000
2 0.90255 0.903 1.000 -0.000
3 0.00006 -0.000 -0.000 1.000
ERR MATRIX NOT POS-DEF
INFO : MIGRAD return code=4

** 23 **MIGRAD 1500 1

START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT.
1.00e-03
FCN=-669400 FROM MIGRAD STATUS=INITIATE 14 CALLS 306
TOTAL
EDM=18612.2 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.95020e-01 4.97679e-03 0.00000e+00 -1.39905e+04
2 fl 7.29924e-01 5.59424e-04 0.00000e+00 5.73115e+03
3 nsig 7.27273e+04 6.92432e+01 0.00000e+00 -2.49489e+02
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-669400 FROM HESSE STATUS=OK 20 CALLS 337
TOTAL
EDM=2.65688 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.95020e-01 3.26843e-04 3.05262e-05 2.45059e+02
2 fl 7.29924e-01 7.70534e-04 7.21313e-05 2.98347e+04
3 nsig 7.27273e+04 2.69674e+02 5.65555e-05 -2.48545e+02
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
MIGRAD TERMINATED WITHOUT CONVERGENCE.
FCN=-669400 FROM MIGRAD STATUS=FAILED 56 CALLS 348
TOTAL
EDM=2.65688 STRATEGY= 1 ERR MATRIX APPROXIMATE
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.95020e-01 3.26843e-04 -0.00000e+00 2.45059e+02
2 fl 7.29924e-01 7.70534e-04 -0.00000e+00 2.98347e+04
3 nsig 7.27273e+04 2.69674e+02 0.00000e+00 -2.48545e+02
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
1.068e-07 -2.052e-11 -1.585e-15
-2.052e-11 5.937e-07 4.586e-11
-1.585e-15 4.586e-11 7.272e+04
ERR MATRIX APPROXIMATE
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.00008 1.000 -0.000 -0.000
2 0.00008 -0.000 1.000 0.000
3 0.00000 -0.000 0.000 1.000
ERR MATRIX APPROXIMATE
INFO : MIGRAD return code=4

** 28 **MIGRAD 1500 1

START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT.
1.00e-03
FCN=-669400 FROM MIGRAD STATUS=INITIATE 10 CALLS 358
TOTAL
EDM=2.1501 STRATEGY= 1 ERR MATRIX APPROXIMATE
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.95020e-01 3.26843e-04 -0.00000e+00 2.45059e+02
2 fl 7.29924e-01 7.70534e-04 -0.00000e+00 2.68385e+04
3 nsig 7.27273e+04 2.69674e+02 0.00000e+00 -2.49489e+02
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
EIGENVALUES OF SECOND-DERIVATIVE MATRIX:
-2.3346e+02 1.0000e+00 2.3546e+02
MINUIT WARNING IN HESSE
============== MATRIX FORCED POS-DEF BY ADDING 233.697311 TO DIAGONAL.
FCN=-669400 FROM HESSE STATUS=NOT POSDEF 18 CALLS 387
TOTAL
EDM=0.593714 STRATEGY= 1 ERR MATRIX NOT
POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.95020e-01 4.46835e-02 1.22105e-05 2.45059e+02
2 fl 7.29924e-01 2.49763e-04 1.60193e-05 -2.90326e+02
3 nsig 7.27273e+04 1.76029e+01 5.65555e-05 -2.48545e+02
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
MIGRAD TERMINATED WITHOUT CONVERGENCE.
FCN=-669400 FROM MIGRAD STATUS=FAILED 68 CALLS 416
TOTAL
EDM=23229.6 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.94904e-01 1.54436e-04 0.00000e+00 -4.82132e+04
2 fl 7.29924e-01 1.12327e-05 0.00000e+00 1.08986e+04
3 nsig 7.27273e+04 1.76029e+01 0.00000e+00 -2.49487e+02
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
2.385e-08 1.621e-10 -3.634e-08
1.621e-10 1.262e-10 -2.029e-10
-3.634e-08 -2.029e-10 3.099e+02
ERR MATRIX NOT POS-DEF
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.09346 1.000 0.093 -0.000
2 0.09346 0.093 1.000 -0.000
3 0.00001 -0.000 -0.000 1.000
ERR MATRIX NOT POS-DEF
INFO : MIGRAD return code=4

** 33 **MIGRAD 1500 1

START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT.
1.00e-03
FCN=-669400 FROM MIGRAD STATUS=INITIATE 14 CALLS 430
TOTAL
EDM=1092.59 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.94904e-01 1.54436e-04 0.00000e+00 -1.29491e+04
2 fl 7.29924e-01 1.12327e-05 0.00000e+00 5.00229e+04
3 nsig 7.27273e+04 1.76029e+01 0.00000e+00 -2.49487e+02
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
EIGENVALUES OF SECOND-DERIVATIVE MATRIX:
-4.0469e-06 1.0000e+00 2.0000e+00
MINUIT WARNING IN HESSE
============== MATRIX FORCED POS-DEF BY ADDING 0.002004 TO DIAGONAL.
FCN=-669400 FROM HESSE STATUS=NOT POSDEF 20 CALLS 460
TOTAL
EDM=0.00472035 STRATEGY= 1 ERR MATRIX NOT
POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.94904e-01 5.57868e-03 3.29352e-05 2.43834e+02
2 fl 7.29924e-01 1.46170e-03 8.63760e-06 -2.89717e+02
3 nsig 7.27273e+04 2.69404e+02 5.65555e-05 -2.48543e+02
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
MIGRAD TERMINATED WITHOUT CONVERGENCE.
FCN=-669400 FROM MIGRAD STATUS=FAILED 83 CALLS 499
TOTAL
EDM=1000.3 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.94843e-01 2.53801e-04 0.00000e+00 -2.42135e+04
2 fl 7.29908e-01 1.50862e-04 0.00000e+00 3.39681e+04
3 nsig 7.27278e+04 2.18137e+02 0.00000e+00 -2.29843e+02
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
6.441e-08 3.567e-08 4.277e-05
3.567e-08 2.276e-08 5.018e-05
4.277e-05 5.018e-05 4.758e+04
ERR MATRIX NOT POS-DEF
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.93157 1.000 0.932 0.001
2 0.93157 0.932 1.000 0.002
3 0.00235 0.001 0.002 1.000
ERR MATRIX NOT POS-DEF
INFO : MIGRAD return code=4

** 38 **MIGRAD 1500 1

START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT.
1.00e-03
FCN=-669400 FROM MIGRAD STATUS=INITIATE 14 CALLS 513
TOTAL
EDM=1790.84 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.94843e-01 2.53801e-04 0.00000e+00 2.43271e+02
2 fl 7.29908e-01 1.50862e-04 0.00000e+00 1.53665e+05
3 nsig 7.27278e+04 2.18137e+02 0.00000e+00 -2.29843e+02
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-669400 FROM HESSE STATUS=OK 22 CALLS 568
TOTAL
EDM=0.0205847 STRATEGY= 1 ERROR MATRIX
ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.92859e-01 2.59862e-02 1.43699e-04 2.29211e+02
2 fl 7.28642e-01 1.12175e-02 6.20998e-05 -3.51933e+02
3 nsig 7.27339e+04 2.69692e+02 5.65579e-05 -5.38181e+00
ERR DEF= 0.5
MINUIT WARNING IN MIGRAD
============== Negative diagonal element 1 in Error Matrix
MINUIT WARNING IN MIGRAD
============== Negative diagonal element 2 in Error Matrix
MINUIT WARNING IN MIGRAD
============== 1.00001 added to diagonal of error matrix
MIGRAD FAILS TO FIND IMPROVEMENT
MACHINE ACCURACY LIMITS FURTHER IMPROVEMENT.
MIGRAD MINIMIZATION HAS CONVERGED.
MIGRAD WILL VERIFY CONVERGENCE AND ERROR MATRIX.
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
MIGRAD TERMINATED WITHOUT CONVERGENCE.
FCN=-669400 FROM MIGRAD STATUS=FAILED 134 CALLS 633
TOTAL
EDM=0.0349461 STRATEGY= 1 ERR MATRIX
APPROXIMATE
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.92278e-01 2.74671e-02 7.68958e-05 2.24406e+02
2 fl 7.28393e-01 1.18444e-02 3.31929e-05 -3.63057e+02
3 nsig 7.27339e+04 2.69692e+02 5.65568e-05 -4.78280e+00
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
7.544e-04 3.252e-04 -5.459e-08
3.252e-04 1.403e-04 -2.355e-08
-5.459e-08 -2.355e-08 7.273e+04
ERR MATRIX APPROXIMATE
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.99955 1.000 1.000 -0.000
2 0.99955 1.000 1.000 -0.000
3 0.00000 -0.000 -0.000 1.000
ERR MATRIX APPROXIMATE
INFO : MIGRAD return code=4

** 43 **MIGRAD 1500 1

START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT.
1.00e-03
FCN=-669400 FROM MIGRAD STATUS=INITIATE 6 CALLS 639
TOTAL
EDM=0.0174727 STRATEGY= 1 ERR MATRIX
APPROXIMATE
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.92278e-01 2.74671e-02 7.68958e-05 2.24405e+02
2 fl 7.28393e-01 1.18444e-02 3.31929e-05 -3.63058e+02
3 nsig 7.27339e+04 2.69692e+02 5.65568e-05 -4.93859e+00
ERR DEF= 0.5
EIGENVALUES OF SECOND-DERIVATIVE MATRIX:
-2.2496e-05 9.8804e-01 2.0120e+00
MINUIT WARNING IN MIGRAD
============== MATRIX FORCED POS-DEF BY ADDING 0.002034 TO DIAGONAL.
MIGRAD FAILS TO FIND IMPROVEMENT
MINUIT WARNING IN HESSE
============== MATRIX FORCED POS-DEF BY ADDING 0.001998 TO DIAGONAL.
FCN=-669400 FROM HESSE STATUS=NOT POSDEF 22 CALLS 775
TOTAL
EDM=67.7382 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 2.82317e-03 1.66587e-05 -6.51380e+05
2 fl 7.27492e-01 1.21434e-03 7.17216e-06 1.51304e+06
3 nsig 7.27338e+04 2.69423e+02 5.65568e-05 -5.57713e+00
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
MIGRAD TERMINATED WITHOUT CONVERGENCE.
FCN=-669400 FROM MIGRAD STATUS=FAILED 153 CALLS 786
TOTAL
EDM=67.7382 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 2.82317e-03 0.00000e+00 -6.51380e+05
2 fl 7.27492e-01 1.21434e-03 -0.00000e+00 1.51304e+06
3 nsig 7.27338e+04 2.69423e+02 0.00000e+00 -5.57713e+00
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
7.970e-06 3.421e-06 2.653e-09
3.421e-06 1.475e-06 1.143e-09
2.653e-09 1.143e-09 7.259e+04
ERR MATRIX NOT POS-DEF
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.99800 1.000 0.998 0.000
2 0.99800 0.998 1.000 0.000
3 0.00000 0.000 0.000 1.000
ERR MATRIX NOT POS-DEF
INFO : MIGRAD return code=4

** 48 **MIGRAD 1500 1

START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT.
1.00e-03
FCN=-669400 FROM MIGRAD STATUS=INITIATE 14 CALLS 800
TOTAL
EDM=5.00525 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 2.82317e-03 0.00000e+00 -1.77049e+05
2 fl 7.27492e-01 1.21434e-03 -0.00000e+00 4.11319e+05
3 nsig 7.27338e+04 2.69423e+02 0.00000e+00 -5.73284e+00
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
EIGENVALUES OF SECOND-DERIVATIVE MATRIX:
-3.0898e-06 1.0000e+00 2.0000e+00
MINUIT WARNING IN HESSE
============== MATRIX FORCED POS-DEF BY ADDING 0.002003 TO DIAGONAL.
FCN=-669400 FROM HESSE STATUS=NOT POSDEF 20 CALLS 831
TOTAL
EDM=2.70981 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 4.15094e-04 2.44944e-06 -8.86087e+05
2 fl 7.27492e-01 1.78546e-04 1.05455e-06 2.05822e+06
3 nsig 7.27338e+04 2.69422e+02 2.26227e-05 -5.58179e+00
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
MIGRAD TERMINATED WITHOUT CONVERGENCE.
FCN=-669400 FROM MIGRAD STATUS=FAILED 55 CALLS 841
TOTAL
EDM=2.70981 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 4.15094e-04 0.00000e+00 -8.86087e+05
2 fl 7.27492e-01 1.78546e-04 -0.00000e+00 2.05822e+06
3 nsig 7.27338e+04 2.69422e+02 0.00000e+00 -5.58179e+00
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
1.723e-07 7.397e-08 2.929e-09
7.397e-08 3.188e-08 1.259e-09
2.929e-09 1.259e-09 7.259e+04
ERR MATRIX NOT POS-DEF
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.99800 1.000 0.998 0.000
2 0.99800 0.998 1.000 0.000
3 0.00000 0.000 0.000 1.000
ERR MATRIX NOT POS-DEF
INFO : MIGRAD return code=4

** 53 **MIGRAD 1500 1

START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT.
1.00e-03
FCN=-669400 FROM MIGRAD STATUS=INITIATE 14 CALLS 855
TOTAL
EDM=2.18231 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 4.15094e-04 0.00000e+00 -7.95175e+05
2 fl 7.27492e-01 1.78546e-04 -0.00000e+00 1.84707e+06
3 nsig 7.27338e+04 2.69422e+02 0.00000e+00 -6.20485e+00
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
EIGENVALUES OF SECOND-DERIVATIVE MATRIX:
-7.8802e-07 1.0000e+00 2.0000e+00
MINUIT WARNING IN HESSE
============== MATRIX FORCED POS-DEF BY ADDING 0.002001 TO DIAGONAL.
FCN=-669400 FROM HESSE STATUS=NOT POSDEF 22 CALLS 887
TOTAL
EDM=2.09617e-07 STRATEGY= 1 ERR MATRIX NOT
POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 9.25073e-05 5.45883e-07 2.07028e+02
2 fl 7.27492e-01 3.97904e-05 2.35016e-07 -4.03253e+02
3 nsig 7.27338e+04 2.69423e+02 4.52454e-05 -5.57654e+00
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
MIGRAD TERMINATED WITHOUT CONVERGENCE.
FCN=-669400 FROM MIGRAD STATUS=FAILED 59 CALLS 900
TOTAL
EDM=4.61768 STRATEGY= 1 ERR MATRIX NOT POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 1.09081e-06 0.00000e+00 -3.27766e+05
2 fl 7.27492e-01 2.55431e-06 0.00000e+00 -4.03257e+02
3 nsig 7.27341e+04 2.69482e+02 -0.00000e+00 1.84037e+00
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
1.190e-12 5.003e-13 -9.139e-08
5.003e-13 6.525e-12 1.522e-08
-9.139e-08 1.522e-08 7.262e+04
ERR MATRIX NOT POS-DEF
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.17956 1.000 0.180 -0.000
2 0.17955 0.180 1.000 0.000
3 0.00032 -0.000 0.000 1.000
ERR MATRIX NOT POS-DEF
INFO : MIGRAD return code=4

** 58 **MIGRAD 1500 1

START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT.
1.00e-03
FCN=-669400 FROM MIGRAD STATUS=INITIATE 14 CALLS 914
TOTAL
EDM=0.0559785 STRATEGY= 1 ERR MATRIX NOT
POS-DEF
EXT PARAMETER APPROXIMATE STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 1.09081e-06 0.00000e+00 -1.47147e+06
2 fl 7.27492e-01 2.55431e-06 0.00000e+00 1.25611e+06
3 nsig 7.27341e+04 2.69482e+02 -0.00000e+00 9.57721e-01
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-669400 FROM HESSE STATUS=OK 22 CALLS 941
TOTAL
EDM=3.21757e-08 STRATEGY= 1 ERROR MATRIX
ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 3.16048e-06 2.95028e-07 2.07027e+02
2 fl 7.27492e-01 3.69832e-06 3.45549e-07 -4.03256e+02
3 nsig 7.27341e+04 2.69693e+02 5.65568e-05 1.93948e+00
ERR DEF= 0.5
MIGRAD FAILS TO FIND IMPROVEMENT
MACHINE ACCURACY LIMITS FURTHER IMPROVEMENT.
MIGRAD MINIMIZATION HAS CONVERGED.
FCN=-669400 FROM MIGRAD STATUS=CONVERGED 53 CALLS 953
TOTAL
EDM=0.0184274 STRATEGY= 1 ERROR MATRIX UNCERTAINTY
0.0 per cent
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 5.90188e-01 3.16071e-06 -0.00000e+00 2.07028e+02
2 fl 7.27492e-01 1.03183e-07 -0.00000e+00 5.17714e+05
3 nsig 7.27340e+04 2.69869e+02 -0.00000e+00 -1.55752e-01
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
9.990e-12 -3.982e-15 3.770e-07
-3.982e-15 1.065e-14 8.237e-08
3.770e-07 8.237e-08 7.283e+04
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.01222 1.000 -0.012 0.000
2 0.01256 -0.012 1.000 0.003
3 0.00300 0.000 0.003 1.000
INFO : MIGRAD return code=0

** 63 **HESSE 1500

COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-669400 FROM HESSE STATUS=OK 20 CALLS 973
TOTAL
EDM=5.79022 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER INTERNAL INTERNAL
NO. NAME VALUE ERROR STEP SIZE VALUE
1 afb 5.90188e-01 3.15260e-02 1.18011e-07 5.90531e-02
2 fl 7.27492e-01 8.97101e-06 8.38002e-07 7.28136e-02
3 nsig 7.27340e+04 2.69692e+02 2.26227e-05 -1.51689e+00
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 36 NPAR= 3 ERR DEF=0.5
9.939e-04 -6.075e-09 0.000e+00
-6.075e-09 8.048e-11 0.000e+00
0.000e+00 0.000e+00 7.273e+04
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.02148 1.000 -0.021 0.000
2 0.02148 -0.021 1.000 0.000
3 0.00000 0.000 0.000 1.000
INFO : Start MINOS loop

** 68 **MINOS 1500 1 2

MINUIT WARNING IN MIGRAD
============== STARTING MATRIX NOT POS-DEFINITE.
POSITIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
1
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
1
MINUIT WARNING IN MNCROS
============== Cannot find slope of the right sign
POSITIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
2
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
2
FCN=-669400 FROM MINOS STATUS=FAILURE 481 CALLS 1454
TOTAL
EDM=5.79022 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 afb 5.90188e-01 3.15260e-02
2 fl 7.27492e-01 8.97101e-06
3 nsig 7.27340e+04 2.69692e+02
ERR DEF= 0.5
INFO : MINOS return code=6

** 73 **MINOS 1500 1 2

MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
1
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
POSITIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
2
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
2
FCN=-669400 FROM MINOS STATUS=PROBLEMS 351 CALLS 1805
TOTAL
EDM=5.79022 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 afb 5.90188e-01 3.15260e-02 2.27510e-02
2 fl 7.27492e-01 8.97101e-06
3 nsig 7.27340e+04 2.69692e+02
ERR DEF= 0.5
INFO : MINOS return code=6

** 78 **MINOS 1500 1 2

                    NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER

1
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
POSITIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
2
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
2
FCN=-669400 FROM MINOS STATUS=PROBLEMS 255 CALLS 2060
TOTAL
EDM=5.79022 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 afb 5.90188e-01 3.15260e-02 2.27224e-02
2 fl 7.27492e-01 8.97101e-06
3 nsig 7.27340e+04 2.69692e+02
ERR DEF= 0.5
INFO : MINOS return code=6

** 83 **MINOS 1500 1 2

                    NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER

1
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
POSITIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
2
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
2
FCN=-669400 FROM MINOS STATUS=PROBLEMS 200 CALLS 2260
TOTAL
EDM=5.79022 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 afb 5.90188e-01 3.15260e-02 1.68439e-02
2 fl 7.27492e-01 8.97101e-06
3 nsig 7.27340e+04 2.69692e+02
ERR DEF= 0.5
INFO : MINOS return code=6

** 88 **MINOS 1500 1 2

                    NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER

1
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
POSITIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
2
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER
2
FCN=-669400 FROM MINOS STATUS=PROBLEMS 195 CALLS 2455
TOTAL
EDM=5.79022 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 afb 5.90188e-01 3.15260e-02 1.68439e-02
2 fl 7.27492e-01 8.97101e-06
3 nsig 7.27340e+04 2.69692e+02
ERR DEF= 0.5
INFO : MINOS return code=6

moneta · July 22, 2016, 4:28pm

Hi,

I see already many errors in your fit. Already using Migrad, probably due to some instability of your model or numerical error. You might try to use the fit option RooFit::Offset(true), it might improve the numerical error calculation

Lorenzo

nsahoo · July 23, 2016, 6:20pm

Hi Lorenzo,

still the same problem exists even though I changed the fit option to RooFit::Offset(true).

[nsahoo@lxplus005 plugins]$ ./fit angular2D …/…/…/…/…/…/BuToKstarMuMu/ntp/sel/v3p3/mc/sig/“sel_BToKstarMuMu_SCN_8TeV_*.root”

RooFit v3.60 – Developed by Wouter Verkerke and David Kirkby
Copyright © 2000-2013 NIKHEF, University of California & Stanford University
All rights reserved, please read roofit.sourceforge.net/license.txt

INFO : ScaleFactor for input data is 1.000
INFO : Plots will be stored to ./plots
INFO : Datacards will be stored to .
INFO : Workspaces will be stored to .
Do you want to redo fitting? [y/n]:y
[#1] INFO:Eval – RooAbsReal::attachToTree(Triggers) TTree Int_t branch Triggers will be converted to double precision
[#1] INFO:Eval – RooTreeDataStore::loadValues(data) Ignored 116260116 out of range events
[#1] INFO:NumericIntegration – RooRealIntegral::init(f_sigA_Int[CosThetaK,CosThetaL]) using numeric integrator RooAdaptiveIntegratorND to calculate Int(CosThetaL,CosThetaK)
INFO: In dommap (/mnt/build/jenkins/workspace/root-release-5.34/BUILDTYPE/Release/COMPILER/native/LABEL/slc6/sources/root_v5.34.36/root/roofit/roofitcore/src/BidirMMapPipe.cxx, line 422): anonymous mmapping works, excellent!
[#1] INFO:Eval – RooAbsTestStatistic::initMPMode: started 4 remote server process.
INFO : Start MIGRAD loop

** 13 **MIGRAD 1500 1

FIRST CALL TO USER FUNCTION AT NEW START POINT, WITH IFLAG=4.
[#1] INFO:Minization – RooNLLVar::evaluatePartition(nll_f_ext_data_GOF2) first = 36367 last = 54550 Likelihood offset now set to 18201.5
[#1] INFO:Minization – RooNLLVar::evaluatePartition(nll_f_ext_data_GOF0) first = 0 last = 18183 Likelihood offset now set to 17977.5
[#1] INFO:Minization – RooNLLVar::evaluatePartition(nll_f_ext_data_GOF1) first = 18183 last = 36367 Likelihood offset now set to 18055.5
[#1] INFO:Minization – RooNLLVar::evaluatePartition(nll_f_ext_data_GOF3) first = 54550 last = 72734 Likelihood offset now set to -641987
START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT. 1.00e-03
[#1] INFO:NumericIntegration – RooRealIntegral::init(f_sigA_Int[CosThetaK,CosThetaL]) using numeric integrator RooAdaptiveIntegratorND to calculate Int(CosThetaL,CosThetaK)
[#1] INFO:NumericIntegration – RooRealIntegral::init(f_sigA_Int[CosThetaK,CosThetaL]) using numeric integrator RooAdaptiveIntegratorND to calculate Int(CosThetaL,CosThetaK)
[#1] INFO:NumericIntegration – RooRealIntegral::init(f_sigA_Int[CosThetaK,CosThetaL]) using numeric integrator RooAdaptiveIntegratorND to calculate Int(CosThetaL,CosThetaK)
[#1] INFO:NumericIntegration – RooRealIntegral::init(f_sigA_Int[CosThetaK,CosThetaL]) using numeric integrator RooAdaptiveIntegratorND to calculate Int(CosThetaL,CosThetaK)
FCN=7.27596e-12 FROM MIGRAD STATUS=INITIATE 12 CALLS 13 TOTAL
EDM= unknown STRATEGY= 1 NO ERROR MATRIX
EXT PARAMETER CURRENT GUESS STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 9.00000e-01 2.00000e+00 2.02225e-01 2.24530e+03
2 fl 6.00000e-01 2.00000e+00 2.01742e-01 -6.86095e+03
3 nsig 1.00000e+04 4.95000e+03 5.15068e-03 -6.24164e+06
ERR DEF= 0.5
MIGRAD MINIMIZATION HAS CONVERGED.
MIGRAD WILL VERIFY CONVERGENCE AND ERROR MATRIX.
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-81644.6 FROM MIGRAD STATUS=CONVERGED 105 CALLS 106 TOTAL
EDM=1.78144e-06 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 afb 6.50310e-01 3.20329e-02 6.19404e-04 1.20139e-01
2 fl 6.81023e-01 1.30665e-02 2.52653e-04 -2.55833e-01
3 nsig 7.27343e+04 2.69693e+02 1.97519e-05 1.25329e+01
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 44 NPAR= 3 ERR DEF=0.5
1.026e-03 8.684e-05 0.000e+00
8.684e-05 1.707e-04 0.000e+00
0.000e+00 0.000e+00 7.273e+04
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.20748 1.000 0.207 0.000
2 0.20748 0.207 1.000 0.000
3 0.00000 0.000 0.000 1.000
INFO : MIGRAD return code=0

** 18 **HESSE 1500

COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-81644.6 FROM HESSE STATUS=OK 16 CALLS 122 TOTAL
EDM=1.78293e-06 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER INTERNAL INTERNAL
NO. NAME VALUE ERROR STEP SIZE VALUE
1 afb 6.50310e-01 3.20352e-02 2.47762e-05 6.50769e-02
2 fl 6.81023e-01 1.30674e-02 1.01061e-05 6.81551e-02
3 nsig 7.27343e+04 2.69693e+02 3.95039e-06 -1.51689e+00
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 44 NPAR= 3 ERR DEF=0.5
1.026e-03 8.699e-05 -4.128e-07
8.699e-05 1.708e-04 -3.499e-08
-4.128e-07 -3.499e-08 7.273e+04
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3
1 0.20779 1.000 0.208 -0.000
2 0.20779 0.208 1.000 -0.000
3 0.00000 -0.000 -0.000 1.000
INFO : Start MINOS loop

** 23 **MINOS 1500 1 2

MINUIT WARNING IN MIGRAD
============== Negative diagonal element 1 in Error Matrix
MINUIT WARNING IN MIGRAD
============== 1 added to diagonal of error matrix
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER 2
FCN=-81644.6 FROM MINOS STATUS=PROBLEMS 232 CALLS 354 TOTAL
EDM=1.78293e-06 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 afb 6.50310e-01 3.20352e-02 -3.15983e-02 3.24937e-02
2 fl 6.81023e-01 1.30674e-02 1.31385e-02
3 nsig 7.27343e+04 2.69693e+02
ERR DEF= 0.5
INFO : MINOS return code=6

** 28 **MINOS 1500 1 2

MINUIT WARNING IN MIGRAD
============== Negative diagonal element 1 in Error Matrix
MINUIT WARNING IN MIGRAD
============== 1 added to diagonal of error matrix
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER 2
FCN=-81644.6 FROM MINOS STATUS=PROBLEMS 234 CALLS 588 TOTAL
EDM=1.78293e-06 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 afb 6.50310e-01 3.20352e-02 -3.15983e-02 3.24937e-02
2 fl 6.81023e-01 1.30674e-02 1.31385e-02
3 nsig 7.27343e+04 2.69693e+02
ERR DEF= 0.5
INFO : MINOS return code=6

** 33 **MINOS 1500 1 2

MINUIT WARNING IN MIGRAD
============== Negative diagonal element 1 in Error Matrix
MINUIT WARNING IN MIGRAD
============== 1 added to diagonal of error matrix
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER 2
FCN=-81644.6 FROM MINOS STATUS=PROBLEMS 231 CALLS 819 TOTAL
EDM=1.78293e-06 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 afb 6.50310e-01 3.20352e-02 -3.15983e-02 3.24937e-02
2 fl 6.81023e-01 1.30674e-02 1.31385e-02
3 nsig 7.27343e+04 2.69693e+02
ERR DEF= 0.5
INFO : MINOS return code=6

** 38 **MINOS 1500 1 2

MINUIT WARNING IN MIGRAD
============== Negative diagonal element 1 in Error Matrix
MINUIT WARNING IN MIGRAD
============== 1 added to diagonal of error matrix
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER 2
FCN=-81644.6 FROM MINOS STATUS=PROBLEMS 232 CALLS 1051 TOTAL
EDM=1.78293e-06 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 afb 6.50310e-01 3.20352e-02 -3.15983e-02 3.24937e-02
2 fl 6.81023e-01 1.30674e-02 1.31385e-02
3 nsig 7.27343e+04 2.69693e+02
ERR DEF= 0.5
INFO : MINOS return code=6

** 43 **MINOS 1500 1 2

MINUIT WARNING IN MIGRAD
============== Negative diagonal element 1 in Error Matrix
MINUIT WARNING IN MIGRAD
============== 1 added to diagonal of error matrix
MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1.
NEGATIVE MINOS ERROR NOT CALCULATED FOR PARAMETER 2
FCN=-81644.6 FROM MINOS STATUS=PROBLEMS 233 CALLS 1284 TOTAL
EDM=1.78293e-06 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER PARABOLIC MINOS ERRORS
NO. NAME VALUE ERROR NEGATIVE POSITIVE
1 afb 6.50310e-01 3.20352e-02 -3.15983e-02 3.24937e-02
2 fl 6.81023e-01 1.30674e-02 1.31385e-02
3 nsig 7.27343e+04 2.69693e+02
ERR DEF= 0.5
INFO : MINOS return code=6

moneta · July 25, 2016, 7:51am

Hi,

The situation with Offset() is clearly better, but not sufficient to make Minos working.
You might try to use Minuit2 if there is a difference. The problem is in your model, so there is no much that I can do. Maybe I would try to scan the likelihood and the profile likelihood (if it works)

Lorenzo