Configure UNCERTAINTY in Sherpa.
The Sherpa configuration variable (also called "state
object") sherpa.unc contains settings of
UNCERTAINTY for calculating confidence intervals in
Sherpa. See ahelp UNCERTAINTY for more
details.
The following table lists each field of sherpa.unc, with a
description and the default value:
|
sigma
|
Specifies the number of sigma (i.e. the change in fit statistic).
|
1
|
|
eps
|
How close (in units of sigma) the fit must get to the threshold sigma
value before the search for the confidence interval bounds is terminated
|
0.01
|
|
remin
|
Change in statistic value that can trigger reminimization
|
0.01
|
To restore the default settings use the Sherpa/S-Lang
module function restore_unc.
The sherpa.unc settings can be changed at the command
line.
sherpa> sherpa.unc.sigma = 2
Set sigma to 5 in the first command and then
list the current and default values of sherpa.unc
and restore the default values.
sherpa> sherpa.unc.sigma = 5
sherpa> list_unc
Parameter Current Default Description
----------------------------------------------------------------------
sigma 5 1 Number of sigma
eps 0.01 0.01 Tolerance for sigma
remin 0.01 0.01 Thresh stat change to reminimize
sherpa> restore_unc
sherpa> list_unc
Parameter Current Default Description
----------------------------------------------------------------------
sigma 1 1 Number of sigma
eps 0.01 0.01 Tolerance for sigma
remin 0.01 0.01 Thresh stat change to reminimize
Create an alias su for sherpa.unc and use it.
sherpa> variable su = sherpa.unc
sherpa> su.sigma = 2
|
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