Add methods to dprior (density and densities).

Will be used as a replacement for priordens.
new-samplers
Stéphane Adjemian (Ryûk) 2023-04-28 12:44:25 +02:00 committed by Stéphane Adjemian (Guts)
parent 03a68ddb89
commit 3c3353b7ed
Signed by: stepan
GPG Key ID: 295C1FE89E17EB3C
2 changed files with 440 additions and 3 deletions

View File

@ -78,7 +78,7 @@ classdef dprior
if ~isempty(o.idweibull)
o.isweibull = true;
end
end
end % dprior (constructor)
function p = draw(o)
% Return a random draw from the prior distribution.
@ -157,7 +157,7 @@ classdef dprior
oob = find( (p(o.idweibull)>o.ub(o.idweibull)) | (p(o.idweibull)<o.lb(o.idweibull)));
end
end
end
end % draw
function P = draws(o, n)
% Return n independent random draws from the prior distribution.
@ -179,7 +179,193 @@ classdef dprior
parfor i=1:n
P(:,i) = draw(o);
end
end
end % draws
function [lpd, dlpd, d2lpd, info] = density(o, x)
% Evaluate the logged prior density at x.
%
% INPUTS
% - o [dprior]
% - x [double] m×1 vector, point where the prior density is evaluated.
%
% OUTPUTS
% - lpd [double] scalar, value of the logged prior density at x.
% - dlpd [double] m×1 vector, first order derivatives.
% - d2lpd [double] m×1 vector, second order derivatives.
%
% REMARKS
% Second order derivatives holder, d2lpd, has the same rank and shape than dlpd because the priors are
% independent (we would have to use a matrix if non orthogonal priors were allowed in Dynare).
%
% EXAMPLE
%
% >> Prior = dprior(bayestopt_, options_.prior_trunc);
% >> lpd = Prior.dsensity(x)
lpd = 0.0;
if nargout>1
dlpd = zeros(1, length(x));
if nargout>2
d2lpd = dlpd;
if nargout>3
info = [];
end
end
end
if o.isuniform
if any(x(o.iduniform)-o.p3(o.iduniform)<0) || any(x(o.iduniform)-o.p4(o.iduniform)>0)
lpd = -Inf ;
if nargout==4
info = o.iduniform((x(o.iduniform)-o.p3(o.iduniform)<0) || (x(o.iduniform)-o.p4(o.iduniform)>0));
end
return
end
lpd = lpd - sum(log(o.p4(o.iduniform)-o.p3(o.iduniform))) ;
if nargout>1
dlpd(o.iduniform) = zeros(length(o.iduniform), 1);
if nargout>2
d2lpd(o.iduniform) = zeros(length(o.iduniform), 1);
end
end
end
if o.isgaussian
switch nargout
case 1
lpd = lpd + sum(lpdfnorm(x(o.idgaussian), o.p6(o.idgaussian), o.p7(o.idgaussian)));
case 2
[tmp, dlpd(o.idgaussian)] = lpdfnorm(x(o.idgaussian), o.p6(o.idgaussian), o.p7(o.idgaussian));
lpd = lpd + sum(tmp);
case {3,4}
[tmp, dlpd(o.idgaussian), d2lpd(o.idgaussian)] = lpdfnorm(x(o.idgaussian), o.p6(o.idgaussian), o.p7(o.idgaussian));
lpd = lpd + sum(lpd);
end
end
if o.isgamma
switch nargout
case 1
lpd = lpd + sum(lpdfgam(x(o.idgamma)-o.p3(o.idgamma), o.p6(o.idgamma), o.p7(o.idgamma)));
if isinf(lpd), return, end
case 2
[tmp, dlpd(o.idgamma)] = lpdfgam(x(o.idgamma)-o.p3(o.idgamma), o.p6(o.idgamma), o.p7(o.idgamma));
lpd = lpd + sum(tmp);
if isinf(lpd), return, end
case 3
[tmp, dlpd(o.idgamma), d2lpd(o.idgamma)] = lpdfgam(x(o.idgamma)-o.p3(o.idgamma), o.p6(o.idgamma), o.p7(o.idgamma));
lpd = lpd + sum(tmp);
if isinf(lpd), return, end
case 4
[tmp, dlpd(o.idgamma), d2lpd(o.idgamma)] = lpdfgam(x(o.idgamma)-o.p3(o.idgamma), o.p6(o.idgamma), o.p7(o.idgamma));
lpd = lpd + sum(tmp);
if isinf(lpd)
info = o.idgamma(isinf(tmp))
return
end
end
end
if o.isbeta
switch nargout
case 1
lpd = lpd + sum(lpdfgbeta(x(o.idbeta), o.p6(o.idbeta), o.p7(o.idbeta), o.p3(o.idbeta), o.p4(o.idbeta)));
if isinf(lpd), return, end
case 2
[tmp, dlpd(o.idbeta)] = lpdfgbeta(x(o.idbeta), o.p6(o.idbeta), o.p7(o.idbeta), o.p3(o.idbeta), o.p4(o.idbeta));
lpd = lpd + sum(tmp);
if isinf(lpd), return, end
case 3
[tmp, dlpd(o.idbeta), d2lpd(o.idbeta)] = lpdfgbeta(x(o.idbeta), o.p6(o.idbeta), o.p7(o.idbeta), o.p3(o.idbeta), o.p4(o.idbeta));
lpd = lpd + sum(tmp);
if isinf(lpd), return, end
case 4
[tmp, dlpd(o.idbeta), d2lpd(o.idbeta)] = lpdfgbeta(x(o.idbeta), o.p6(o.idbeta), o.p7(o.idbeta), o.p3(o.idbeta), o.p4(o.idbeta));
lpd = lpd + sum(tmp);
if isinf(lpd)
info = o.idbeta(isinf(tmp));
return
end
end
end
if o.isinvgamma1
switch nargout
case 1
lpd = lpd + sum(lpdfig1(x(o.idinvgamma1)-o.p3(o.idinvgamma1), o.p6(o.idinvgamma1), o.p7(o.idinvgamma1)));
if isinf(lpd), return, end
case 2
[tmp, dlpd(o.idinvgamma1)] = lpdfig1(x(o.idinvgamma1)-o.p3(o.idinvgamma1), o.p6(o.idinvgamma1), o.p7(o.idinvgamma1));
lpd = lpd + sum(tmp);
if isinf(lpd), return, end
case 3
[tmp, dlpd(o.idinvgamma1), d2lpd(o.idinvgamma1)] = lpdfig1(x(o.idinvgamma1)-o.p3(o.idinvgamma1), o.p6(o.idinvgamma1), o.p7(o.idinvgamma1));
lpd = lpd + sum(tmp);
if isinf(lpd), return, end
case 4
[tmp, dlpd(o.idinvgamma1), d2lpd(o.idinvgamma1)] = lpdfig1(x(o.idinvgamma1)-o.p3(o.idinvgamma1), o.p6(o.idinvgamma1), o.p7(o.idinvgamma1));
lpd = lpd + sum(tmp);
if isinf(lpd)
info = o.idinvgamma1(isinf(tmp));
return
end
end
end
if o.isinvgamma2
switch nargout
case 1
lpd = lpd + sum(lpdfig2(x(o.idinvgamma2)-o.p3(o.idinvgamma2), o.p6(o.idinvgamma2), o.p7(o.idinvgamma2)));
if isinf(lpd), return, end
case 2
[tmp, dlpd(o.idinvgamma2)] = lpdfig2(x(o.idinvgamma2)-o.p3(o.idinvgamma2), o.p6(o.idinvgamma2), o.p7(o.idinvgamma2));
lpd = lpd + sum(tmp);
if isinf(lpd), return, end
case 3
[tmp, dlpd(o.idinvgamma2), d2lpd(o.idinvgamma2)] = lpdfig2(x(o.idinvgamma2)-o.p3(o.idinvgamma2), o.p6(o.idinvgamma2), o.p7(o.idinvgamma2));
lpd = lpd + sum(tmp);
if isinf(lpd), return, end
case 4
[tmp, dlpd(o.idinvgamma2), d2lpd(o.idinvgamma2)] = lpdfig2(x(o.idinvgamma2)-o.p3(o.idinvgamma2), o.p6(o.idinvgamma2), o.p7(o.idinvgamma2));
lpd = lpd + sum(tmp);
if isinf(lpd)
info = o.idinvgamma2(isinf(tmp));
return
end
end
end
if o.isweibull
switch nargout
case 1
lpd = lpd + sum(lpdfgweibull(x(o.idweibull), o.p6(o.idweibull), o.p7(o.idweibull)));
if isinf(lpd), return, end
case 2
[tmp, dlpd(o.idweibull)] = lpdfgweibull(x(o.idweibull), o.p6(o.idweibull), o.p7(o.idweibull));
lpd = lpd + sum(tmp);
if isinf(lpd), return, end
case 3
[tmp, dlpd(o.idweibull), d2lpd(o.idweibull)] = lpdfgweibull(x(o.idweibull), o.p6(o.idweibull), o.p7(o.idweibull));
lpd = lpd + sum(tmp);
if isinf(lpd), return, end
case 4
[tmp, dlpd(o.idweibull), d2lpd(o.idweibull)] = lpdfgweibull(x(o.idweibull), o.p6(o.idweibull), o.p7(o.idweibull));
lpd = lpd + sum(tmp);
if isinf(lpd)
info = o.idweibull(isinf(tmp));
return
end
end
end
end % density
function lpd = densities(o, X)
% Evaluate the logged prior densities at X (for each column).
%
% INPUTS
% - o [dprior]
% - X [double] m×n matrix, n points where the prior density is evaluated.
%
% OUTPUTS
% - lpd [double] 1×n, values of the logged prior density at X.
n = columns(X);
lpd = NaN(1, n);
parfor i=1:n
lpd(i) = density(o, X(:,i));
end
end % densities
end % methods
end % classdef --*-- Unit tests --*--
@ -374,3 +560,195 @@ end % classdef --*-- Unit tests --*--
%$ end
%$ T = all(t);
%@eof:2
%@test:3
%$ % Fill global structures with required fields...
%$ prior_trunc = 1e-10;
%$ p0 = repmat([1; 2; 3; 4; 5; 6; 8], 2, 1); % Prior shape
%$ p1 = .4*ones(14,1); % Prior mean
%$ p2 = .2*ones(14,1); % Prior std.
%$ p3 = NaN(14,1);
%$ p4 = NaN(14,1);
%$ p5 = NaN(14,1);
%$ p6 = NaN(14,1);
%$ p7 = NaN(14,1);
%$
%$ for i=1:14
%$ switch p0(i)
%$ case 1
%$ % Beta distribution
%$ p3(i) = 0;
%$ p4(i) = 1;
%$ [p6(i), p7(i)] = beta_specification(p1(i), p2(i)^2, p3(i), p4(i));
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 1);
%$ case 2
%$ % Gamma distribution
%$ p3(i) = 0;
%$ p4(i) = Inf;
%$ [p6(i), p7(i)] = gamma_specification(p1(i), p2(i)^2, p3(i), p4(i));
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 2);
%$ case 3
%$ % Normal distribution
%$ p3(i) = -Inf;
%$ p4(i) = Inf;
%$ p6(i) = p1(i);
%$ p7(i) = p2(i);
%$ p5(i) = p1(i);
%$ case 4
%$ % Inverse Gamma (type I) distribution
%$ p3(i) = 0;
%$ p4(i) = Inf;
%$ [p6(i), p7(i)] = inverse_gamma_specification(p1(i), p2(i)^2, p3(i), 1, false);
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 4);
%$ case 5
%$ % Uniform distribution
%$ [p1(i), p2(i), p6(i), p7(i)] = uniform_specification(p1(i), p2(i), p3(i), p4(i));
%$ p3(i) = p6(i);
%$ p4(i) = p7(i);
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 5);
%$ case 6
%$ % Inverse Gamma (type II) distribution
%$ p3(i) = 0;
%$ p4(i) = Inf;
%$ [p6(i), p7(i)] = inverse_gamma_specification(p1(i), p2(i)^2, p3(i), 2, false);
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 6);
%$ case 8
%$ % Weibull distribution
%$ p3(i) = 0;
%$ p4(i) = Inf;
%$ [p6(i), p7(i)] = weibull_specification(p1(i), p2(i)^2, p3(i));
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 8);
%$ otherwise
%$ error('This density is not implemented!')
%$ end
%$ end
%$
%$ BayesInfo.pshape = p0;
%$ BayesInfo.p1 = p1;
%$ BayesInfo.p2 = p2;
%$ BayesInfo.p3 = p3;
%$ BayesInfo.p4 = p4;
%$ BayesInfo.p5 = p5;
%$ BayesInfo.p6 = p6;
%$ BayesInfo.p7 = p7;
%$
%$ % Call the tested routine
%$ try
%$ Prior = dprior(BayesInfo, prior_trunc, false);
%$
%$ % Compute density at the prior mode
%$ lpdstar = Prior.density(p5);
%$
%$ % Draw random deviates in a loop and evaluate the density.
%$ LPD = NaN(10000,1);
%$ parfor i = 1:10000
%$ x = Prior.draw();
%$ LPD(i) = Prior.density(x);
%$ end
%$ t(1) = true;
%$ catch
%$ t(1) = false;
%$ end
%$
%$ if t(1)
%$ t(2) = all(LPD<=lpdstar);
%$ end
%$ T = all(t);
%@eof:3
%@test:4
%$ % Fill global structures with required fields...
%$ prior_trunc = 1e-10;
%$ p0 = repmat([1; 2; 3; 4; 5; 6; 8], 2, 1); % Prior shape
%$ p1 = .4*ones(14,1); % Prior mean
%$ p2 = .2*ones(14,1); % Prior std.
%$ p3 = NaN(14,1);
%$ p4 = NaN(14,1);
%$ p5 = NaN(14,1);
%$ p6 = NaN(14,1);
%$ p7 = NaN(14,1);
%$
%$ for i=1:14
%$ switch p0(i)
%$ case 1
%$ % Beta distribution
%$ p3(i) = 0;
%$ p4(i) = 1;
%$ [p6(i), p7(i)] = beta_specification(p1(i), p2(i)^2, p3(i), p4(i));
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 1);
%$ case 2
%$ % Gamma distribution
%$ p3(i) = 0;
%$ p4(i) = Inf;
%$ [p6(i), p7(i)] = gamma_specification(p1(i), p2(i)^2, p3(i), p4(i));
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 2);
%$ case 3
%$ % Normal distribution
%$ p3(i) = -Inf;
%$ p4(i) = Inf;
%$ p6(i) = p1(i);
%$ p7(i) = p2(i);
%$ p5(i) = p1(i);
%$ case 4
%$ % Inverse Gamma (type I) distribution
%$ p3(i) = 0;
%$ p4(i) = Inf;
%$ [p6(i), p7(i)] = inverse_gamma_specification(p1(i), p2(i)^2, p3(i), 1, false);
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 4);
%$ case 5
%$ % Uniform distribution
%$ [p1(i), p2(i), p6(i), p7(i)] = uniform_specification(p1(i), p2(i), p3(i), p4(i));
%$ p3(i) = p6(i);
%$ p4(i) = p7(i);
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 5);
%$ case 6
%$ % Inverse Gamma (type II) distribution
%$ p3(i) = 0;
%$ p4(i) = Inf;
%$ [p6(i), p7(i)] = inverse_gamma_specification(p1(i), p2(i)^2, p3(i), 2, false);
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 6);
%$ case 8
%$ % Weibull distribution
%$ p3(i) = 0;
%$ p4(i) = Inf;
%$ [p6(i), p7(i)] = weibull_specification(p1(i), p2(i)^2, p3(i));
%$ p5(i) = compute_prior_mode([p6(i) p7(i)], 8);
%$ otherwise
%$ error('This density is not implemented!')
%$ end
%$ end
%$
%$ BayesInfo.pshape = p0;
%$ BayesInfo.p1 = p1;
%$ BayesInfo.p2 = p2;
%$ BayesInfo.p3 = p3;
%$ BayesInfo.p4 = p4;
%$ BayesInfo.p5 = p5;
%$ BayesInfo.p6 = p6;
%$ BayesInfo.p7 = p7;
%$
%$ % Call the tested routine
%$ try
%$ Prior = dprior(BayesInfo, prior_trunc, false);
%$ mu = NaN(14,1);
%$
%$ for i=1:14
%$ % Define conditional density (it's also a marginal since priors are orthogonal)
%$ f = @(x) exp(Prior.densities(substitute(p5, i, x)));
%$ % TODO: Check the version of Octave we use (integral is available as a compatibility wrapper in latest Octave version)
%$ m = integral(f, p3(i), p4(i));
%$ density = @(x) f(x)/m; % rescaling is required since the probability mass depends on the conditioning.
%$ % Compute the conditional expectation
%$ mu(i) = integral(@(x) x.*density(x), p3(i), p4(i));
%$ end
%$
%$ t(1) = true;
%$ catch
%$ t(1) = false;
%$ end
%$
%$ if t(1)
%$ t(2) = all(abs(mu-.4)<1e-6);
%$ end
%$ T = all(t);
%@eof:4

59
matlab/substitute.m Normal file
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@ -0,0 +1,59 @@
function v = substitute(v, i, x)
% Substitute a scalar in a vector.
%
% INPUTS
% - v [double] m×1 vector
% - i [integer] scalar, index for the scalar to be replaced
% - x [double] scalar or 1×n vector.
%
% OUTPUTS
% - v [double] m×1 vector or m×n matrix (with substituted value(s))
%
% REMARKS
% If x is a vector with n elements, then n substitutions are performed (returning n updated vectors in a matrix with n columns)
%
% EXAMPLES
% >> v = ones(2,1);
% >> substitude(v, 1, 0)
%
% ans = %
%
% 0
%
% 1
%
% >> substitute(v, 1, [3 4])
%
% ans =
%
% 3 4
% 1 1
% Copyright © 2023 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/>.
assert(isvector(v), 'First input argument must be a vector.')
assert(isvector(x), 'Last input argument must be a scalar or a vector.')
assert(isscalar(i) && isint(i) && i>0 && i<=length(v), 'Second input argument must be a scalar integer')
if length(x)==1
v(i) = x;
else
v = repmat(v, 1, length(x));
v(i,:) = x;
end