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ITE / code / estimators / meta_estimators / KEJS_DJS_initialization.m

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function [co] = KEJS_DJS_initialization(mult,post_init)
%function [co] = KEJS_DJS_initialization(mult)
%function [co] = KEJS_DJS_initialization(mult,post_init)
%Initialization of the exponentiated Jensen-Shannon kernel estimator defined according to the relation: K_JS(f_1,f_2) = exp[-u x D_JS(f_1,f_2)], where D_JS is the Jensen-Shannon divergence, u>0.
%
%Note:
%   1)The estimator is treated as a cost object (co).
%   2)We use the naming convention 'K<name>_initialization' to ease embedding new estimators for kernels on distributions.
%   3)This is a meta method: the Jensen-Shannon divergence estimator can arbitrary.
%
%INPUT:
%   mult: is a multiplicative constant relevant (needed) in the estimation; '=1' means yes, '=0' no.
%   post_init: {field_name1,field_value1,field_name2,field_value2,...}; cell array containing the names and the values of the cost object fields that are to be used
%   (instead of their default values). For further details, see 'post_initialization.m'.
%OUTPUT:
%   co: cost object (structure).

%Copyright (C) 2013 Zoltan Szabo ("http://www.gatsby.ucl.ac.uk/~szabo/", "zoltan (dot) szabo (at) gatsby (dot) ucl (dot) ac (dot) uk")
%
%This file is part of the ITE (Information Theoretical Estimators) Matlab/Octave toolbox.
%
%ITE is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
%the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
%
%This software 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 License for more details.
%
%You should have received a copy of the GNU General Public License along with ITE. If not, see <http://www.gnu.org/licenses/>.

%mandatory fields  (following the template structure of the estimators to make uniform usage of the estimators possible):
    co.name = 'EJS_DJS';
    co.mult = mult;
    
%other fields:
    co.u = 1; %assumption: u>0
    co.member_name = 'JensenShannon_HShannon'; %you can change it to any Jensen-Shannon divergence estimator

%post initialization (put it _before_ initialization of the members in case of a meta estimator):    
    if nargin==2 %there are given (name,value) cost object fields
        co = post_initialization(co,post_init);
    end 

%initialization of the member(s):
    %co.member_co = D_initialization(co.member_name,mult);
    co.member_co = D_initialization(co.member_name,mult,{'w',[1/2,1/2]}); %{'w',[1/2 1/2]}: the 'w' weight field of the member is also set here; note: if the Jensen-Shannon divergence estimator is restricted to w=[1/2, 1/2], then of course '{...}' can be discarded.