
cterror
=======

Computes parameter errors for a source model from the likelihood profiles.


Synopsis
--------

This tool computes the parameter errors for a specific source model using
the likelihood profiles. Starting from the maximum likelihood model parameters,
the tool finds the minimum and maximum model parameters that lead to a decrease
of the likelihood that corresponds to a given confidence level. By default a
confidence level of 68% is used, but this level can be adjusted using the hidden
confidence parameter.

cterror generates an output model XML file that contains the values of the 
best fitting model parameters. For all free parameters, an error attribute
is added that provides the statistical uncertainty in the parameter estimate
as obtained from the likelihood profile. While cterror computes asymmetrical
errors, which are written into the log file, the XML file will contain the 
mean error that is obtained by computing the mean of the negative and the
positive parameter errors.


General parameters
------------------

inobs [file]
    Input event list, counts cube or observation definition XML file.
 	 	 
inmodel [file]
    Input model XML file.
 	 	 
srcname [string]
    Name of source model for which the parameter errors should be computed.
 	 	 
expcube [file]
    Input exposure cube file (only needed for stacked analysis).

psfcube [file]
    Input PSF cube file (only needed for stacked analysis).

bkgcube [file]
    Input background cube file (only needed for stacked analysis).

caldb [string]
    Calibration database.
 	 	 
irf [string]
    Instrumental response function.
 	 	 
(edisp = no) [boolean]
    Applies energy dispersion to response computation.
 	 	 
outmodel [file]
    Output model XML file with updated error information.
 	 	 
(confidence = 0.68) [real]
    Confidence level for error computation.
    
(tol = 1e-3) [real]
    Computation tolerance.
   
(max_iter = 50) [integer]
    Maximum number of iterations before stopping the likelihood
    profil computations.


Standard parameters
-------------------

(chatter = 2) [integer]
    Verbosity of the executable:
     chatter = 0: no information will be logged
     
     chatter = 1: only errors will be logged
     
     chatter = 2: errors and actions will be logged
     
     chatter = 3: report about the task execution
     
     chatter = 4: detailed report about the task execution
 	 	 
(clobber = yes) [boolean]
    Specifies whether an existing output file should be overwritten.
 	 	 
(debug = no) [boolean]
    Enables debug mode. In debug mode the executable will dump any log file output to the console.
 	 	 
(mode = ql) [string]
    Mode of automatic parameters (default is "ql", i.e. "query and learn").

(logfile = cterror.log) [string]
    Name of log file.


Related tools or scripts
------------------------

ctlike
ctulimit
ctbutterfly
