Core_mind.pro

;
; Copyright (c) 2013-2024, Marc De Graef Research Group/Carnegie Mellon University
; All rights reserved.
;
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;
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;
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; ###################################################################
;--------------------------------------------------------------------------
; EMsoft:Core_mind.pro
;--------------------------------------------------------------------------
;
; PROGRAM: Core_mind.pro
;
;> @author Marc De Graef, Carnegie Mellon University
;
;> @brief special event handler for all the CW_BGROUP calls, since CW_BGROUP does not support event_pro
;
;> @date 03/19/14 MDG 1.0 first version
;--------------------------------------------------------------------------
function Core_mind,ndhist,level=level
;
; computes the mutual information for a set of n images
;
; input: the normalized n-dimensional histogram, as computed by new_hist_nd(array,binsize,/normalize)
;
; output: the higher dimensional mutual information
;
; The idea is that we compute the n-dimensional joint histogram only once,
; and then project it down into lower dimensions for the computation of 
; all the image entropies...
;
; This routine calls itself recursively with the lower dimensional joint histograms
; as input ...
;
; version 1, MDG/EIC, 3/17/10
;> @date 10/20/15 MDG 1.1 adapted for Efit.pro routine

if arg_present(level) then level += 1 else level = 0

; get the dimensions to determine the sign of this contribution
sz = size(ndhist,/dimension)
szsz = size(sz,/dimension)
if (szsz[0] mod 2 eq 0) then sign=-1 else sign=+1

; compute the entropy for this level of recursion
q = where(ndhist ne 0.0,cnt)
if (cnt ne 0) then H = -sign*total(ndhist[q] * alog(ndhist[q]))/factorial(level) else begin
	print,'Warning: All joint histogram entries are zero'
	return,-1
endelse

; now recursively call this routine for all the lower level projections
if (szsz[0] gt 1) then begin
  for i=1,szsz[0] do begin
    H += Core_mind(reform(total(ndhist,i)),level=level)
    level -= 1
  endfor
endif

return,H
end