dynare/matlab/estimation/lpdfgbeta.m

63 lines
2.2 KiB
Matlab

function [ldens,Dldens,D2ldens] = lpdfgbeta(x,a,b,aa,bb)
% Evaluates the logged BETA PDF at x.
%
% INPUTS
% x [double] m*n matrix of locations,
% a [double] m*n matrix of First BETA distribution parameters,
% b [double] m*n matrix of Second BETA distribution parameters,
% aa [double] m*n matrix of lower bounds for (generalized) distribution,
% bb [double] m*n matrix of upper bounds for (generalized) distribution
%
% OUTPUTS
% ldens [double] m*n matrix of logged (generalized) BETA densities.
% Dldens [double] m*n matrix of first derivatives of logged (generalized) BETA densities.
% D2ldens [double] m*n matrix of second derivatives of logged matrix of logged (generalized) BETA densities.
%
% SPECIAL REQUIREMENTS
% none
% Copyright © 2003-2021 Dynare Team
%
% This file is part of Dynare.
%
% Dynare 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.
%
% Dynare 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 Dynare. If not, see <https://www.gnu.org/licenses/>.
ldens = -Inf( size(x) ) ;
idx = find( (x-aa)>0 & (x-bb)<0 ) ;
if length(a)==1
ldens(idx) = -betaln(a,b) + (a-1)*log(x(idx)-aa) + (b-1)*log(bb-x(idx)) - (a+b-1)*log(bb-aa) ;
else
ldens(idx) = -betaln(a(idx),b(idx)) + (a(idx)-1).*log(x(idx)-aa(idx)) + (b(idx)-1).*log(bb(idx)-x(idx)) - (a(idx)+b(idx)-1).*log(bb(idx)-aa(idx));
end
if nargout >1
Dldens = ldens ;
if length(a)==1
Dldens(idx) = (a-1)./(x(idx)-aa) - (b-1)./(bb-x(idx)) ;
else
Dldens(idx) = (a(idx)-1)./(x(idx)-aa(idx)) - (b(idx)-1)./(bb(idx)-x(idx));
end
end
if nargout == 3
D2ldens = ldens ;
if length(a)==1
D2ldens(idx) = -(a-1)./(x(idx)-aa).^2 - (b-1)./(bb-x(idx)).^2 ;
else
D2ldens(idx) = -(a(idx)-1)./(x(idx)-aa(idx)).^2 - (b(idx)-1)./(bb(idx)-x(idx)).^2;
end
end