Ahelp: sherpa.regproj - CIAO 3.4

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AHELP for CIAO 3.4

sherpa.regproj

Context: sherpa

Synopsis

Configure REGION-PROJECTION in Sherpa.

Syntax

sherpa.regproj.[field]

Description

The Sherpa configuration variable (also called "state object") sherpa.regproj contains settings of REGION-PROJECTION for creating a contour plot of confidence regions using the PROJECTION algorithm in Sherpa. See ahelp REGION-PROJECTION for more details.

The following table lists each field of sherpa.regproj, with a description and the default value:

Field Name	Description	Default
fast	Use levenberg-marquardt (or simplex if using Cash) in place of current optimization method (0 = false, 1 = true)	1
expfac	Relative size of the plot if the grid limits are determined automatically	3
arange	Whether the grid limits are to be determined automatically (0 = false, 1 = true)	1
min	Minimum x, y values if plot limits set manually	[0,0]
max	Maximum x, y values if plot limits set manually	[0,0]
log	Use log scale for plot axes (0 = false, 1 = true)	[0,0]
nloop	Number of grid points for each axis	[10,10]
sigma	Number of sigma for each countour (e.g., [1,2,3] corresponds to contours of 1, 2 and 3 sigma)	[1,2,3]

Example 1

Set the method to LEVENBERG-MARQUARDT and grid limits for both parameter, e.g. the limits for the plot axis, and finally set the contour levels to 2, 4 and 6 sigma.

sherpa> sherpa.regproj.fast = 1
sherpa> sherpa.regproj.min=[0.1,1.5]
sherpa> sherpa.regproj.max=[1.,2.5]
sherpa> sherpa.regproj.sigma = [2,4,6]

Example 2

List the current and default values of the sherpa.regproj and restore the default values:

sherpa> sherpa.regproj.log = [1,1]
sherpa> sherpa.regproj.sigma = [1,3,5]
sherpa> list_regproj

Parameter   Current         Default                        Description
----------------------------------------------------------------------
fast              1               1    Switch to LM/simplex: 0(n)/1(y)
expfac            3               3          Expansion factor for grid
arange            0               1              Auto-range: 0(n)/1(y)
min           [0,0]           [0,0]          Minimum values, each axis
max           [0,0]           [0,0]          Maximum values, each axis
log           [1,1]           [0,0]  Log-spacing: 0(n)/1(y), each axis
nloop       [10,10]         [10,10]   Number of grid points, each axis
sigma       [1,3,5]         [1,2,3]      Number of sigma, each contour

sherpa> restore_regproj

sherpa> list_regproj

Parameter   Current         Default                        Description
----------------------------------------------------------------------
fast              1               1    Switch to LM/simplex: 0(n)/1(y)
expfac            3               3          Expansion factor for grid
arange            1               1              Auto-range: 0(n)/1(y)
min           [0,0]           [0,0]          Minimum values, each axis
max           [0,0]           [0,0]          Maximum values, each axis
log           [0,0]           [0,0]  Log-spacing: 0(n)/1(y), each axis
nloop       [10,10]         [10,10]   Number of grid points, each axis
sigma       [1,2,3]         [1,2,3]      Number of sigma, each contour

Example 3

Create alias sr for sherpa.regproj and use it:

sherpa> variable sr = sherpa.regproj
sherpa> sr.fast = 0
sherpa> sr.sigma = [1,1.6,2.6]

Bugs

See the Sherpa bug pages online for an up-to-date listing of known bugs.

Hardcopy (PDF): A4 | Letter

Last modified: December 2006

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