function shapelets_concentration,decomp, $
RATIO=ratio, $
KURTOSIS=kurtosis
;$Id: shapelets_concentration.pro, v2$
;
; Copyright © 2005 Richard Massey and Alexandre Refregier.
;
; This file is a part of the Shapelets analysis code.
; www.astro.caltech.edu/~rjm/shapelets/
;
; The Shapelets code is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public Licence as published
; by the Free Software Foundation; either version 2 of the Licence, or
; (at your option) any later version.
;
; The Shapelets code is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public Licence for more details.
;
; You should have received a copy of the GNU General Public Licence
; along with the Shapelets code; if not, write to the Free Software
; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
;
;+
; NAME:
; SHAPELETS_CONCENTRATION
;
; PURPOSE:
; Returns concentration morphology index of a Cartesian decomp structure.
;
; CATEGORY:
; Shapelets.
;
; INPUTS:
; DECOMP - A Cartesian shapelet decomposition.
;
; KEYWORD PARAMETERS:
; KURTOSIS - Calculate the object kurtosis.
; RATIO - Calculate the ratio of R/beta.
; ERROR - Simultaneously calculate the error on the concentration.
;
; OUTPUTS:
; CONCENTRATION - A floating point variable containing the object's
; concentration morphology index.
; If /ERROR is set, this becomes a vector
; [concentration,concentration_error]
;
; OPTIONAL OUTPUTS:
; FLUX - Flux of object (needed to calculate asymmetry anyway).
; RSQUARED - R^2 size of object (needed to calculate asymmetry anyway).
; MATRIX - Cartesian to polar shapelet conversion matrix.
;
; EXAMPLE USE:
; result = shapelets_concentration(decomp,/error)
;
; TO DO:
; Add the more complicated option involving integration within
; various Petrosian radii suggested in Polar Shapelets.
;
; MODIFICATION HISTORY:
; Jul 05 - Ability to accept polar decomp structures added by RM.
; Jun 05 - Series that doesn't converge in Polar Shapelets hacked in by RM.
; Jun 04 - Written by Richard Massey.
;-
COMPILE_OPT idl2
if keyword_set(kurtosis) then begin
; Backwardly compatible
if not tag_exist(decomp,"polar") then decomp=create_struct(decomp,"polar",0B)
; Remember input variable, so that it can be restored later
decomp_input=decomp
; Calculate polar shapelet coefficients
shapelets_polar_convert,decomp,/polar
; Calculate total flux
m0=where(decomp.m eq 0,n_m0)
if n_m0 gt 0 then begin
; Calculate dimensionless equlvalent of flux
flux=total(float(decomp.coeffs[m0]))
; Calculate concentration
if flux eq 0. then concentration=!values.f_nan else begin
; Calculate weights
weights=fltarr((decomp.n_max+2)/2)
weights[0]=1. ; Overall normalisation unimportant
if decomp.n_max ge 2 then begin
weights[1]=weights[0]
if decomp.n_max ge 4 then begin
for n=4,decomp.n_max,2 do begin
weights[n/2]=( 10.*weights[n/2-1] + (n-2)*weights[n/2-2] ) /n
endfor
endif
endif
; Combine coefficients
concentration=float(total(decomp.coeffs[m0]*weights))/flux
; Rescale to roughly match spread of Chirs Conselice's concentration values
;concentration=-50*concentration+5
endelse
endif
; Restore input variable
decomp=decomp_input
endif else if keyword_set(ratio) then begin
; Calculate R^2 size
rsquared=shapelets_rsquared(decomp,flux=flux,error=error,cartesian=cartesian,polar=polar)
; Calculate concentration
if decomp.beta eq 0. then concentration=!values.f_nan else $
concentration=sqrt(rsquared)/decomp.beta
endif else begin
message,"No method specified!"
endelse
return,concentration
end
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| Last modified on 2nd Mar 2009 by Richard Massey. |