Fix a bug in likelihood calculation.
parent
78bb829899
commit
8ef134d960
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@ -64,7 +64,7 @@ end
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% Get initial condition for the state vector.
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StateVectorMean = ReducedForm.StateVectorMean;
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StateVectorVarianceSquareRoot = reduced_rank_cholesky(ReducedForm.StateVectorVariance)';
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StateVectorVarianceSquareRoot = chol(ReducedForm.StateVectorVariance)';%reduced_rank_cholesky(ReducedForm.StateVectorVariance)';
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state_variance_rank = size(StateVectorVarianceSquareRoot,2);
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Q_lower_triangular_cholesky = chol(Q)';
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if pruning
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@ -76,7 +76,7 @@ end
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set_dynare_seed('default');
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% Initialization of the likelihood.
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const_lik = log(2*pi)*number_of_observed_variables;
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const_lik = log(2*pi)*number_of_observed_variables +log(det(H));
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lik = NaN(sample_size,1);
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LIK = NaN;
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@ -125,11 +125,11 @@ for t=1:sample_size
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tmp = tmp + nodes_weights(i)*local_state_space_iteration_2(yhat,nodes(i,:)*ones(1,number_of_particles),ghx,ghu,constant,ghxx,ghuu,ghxu,ThreadsOptions.local_state_space_iteration_2);
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end
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end
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PredictedObservedMean = weights*(tmp(mf1,:)');
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%PredictedObservedMean = weights*(tmp(mf1,:)');
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PredictionError = bsxfun(@minus,Y(:,t),tmp(mf1,:));
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dPredictedObservedMean = bsxfun(@minus,tmp(mf1,:),PredictedObservedMean');
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PredictedObservedVariance = bsxfun(@times,weights,dPredictedObservedMean)*dPredictedObservedMean' +H;
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wtilde = exp(-.5*(const_lik+log(det(PredictedObservedVariance))+sum(PredictionError.*(PredictedObservedVariance\PredictionError),1))) ;
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%dPredictedObservedMean = bsxfun(@minus,tmp(mf1,:),PredictedObservedMean');
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%PredictedObservedVariance = bsxfun(@times,weights,dPredictedObservedMean)*dPredictedObservedMean' +H;
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wtilde = exp(-.5*(const_lik+sum(PredictionError.*(H\PredictionError),1))) ;
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tau_tilde = weights.*wtilde ;
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sum_tau_tilde = sum(tau_tilde) ;
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lik(t) = log(sum_tau_tilde) ;
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@ -148,11 +148,11 @@ for t=1:sample_size
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tmp = local_state_space_iteration_2(yhat,epsilon,ghx,ghu,constant,ghxx,ghuu,ghxu,ThreadsOptions.local_state_space_iteration_2);
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end
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StateVectors = tmp(mf0,:);
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PredictedObservedMean = mean(tmp(mf1,:),2);
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%PredictedObservedMean = mean(tmp(mf1,:),2);
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PredictionError = bsxfun(@minus,Y(:,t),tmp(mf1,:));
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dPredictedObservedMean = bsxfun(@minus,tmp(mf1,:),PredictedObservedMean);
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PredictedObservedVariance = (dPredictedObservedMean*dPredictedObservedMean')/number_of_particles + H;
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lnw = exp(-.5*(const_lik+log(det(PredictedObservedVariance))+sum(PredictionError.*(PredictedObservedVariance\PredictionError),1)));
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%dPredictedObservedMean = bsxfun(@minus,tmp(mf1,:),PredictedObservedMean);
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%PredictedObservedVariance = (dPredictedObservedMean*dPredictedObservedMean')/number_of_particles + H;
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lnw = exp(-.5*(const_lik+sum(PredictionError.*(H\PredictionError),1)));
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wtilde = lnw.*factor ;
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weights = wtilde/sum(wtilde);
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end
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@ -113,7 +113,7 @@ else
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StateVectorMean = PredictedStateMean + KalmanFilterGain*(obs - PredictedObservedMean);
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StateVectorVariance = PredictedStateVariance - KalmanFilterGain*PredictedObservedVariance*KalmanFilterGain';
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StateVectorVariance = .5*(StateVectorVariance+StateVectorVariance');
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StateVectorVarianceSquareRoot = reduced_rank_cholesky(StateVectorVariance)';
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StateVectorVarianceSquareRoot = chol(StateVectorVariance)';%reduced_rank_cholesky(StateVectorVariance)';
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end
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ProposalStateVector = StateVectorVarianceSquareRoot*randn(size(StateVectorVarianceSquareRoot,2),1)+StateVectorMean ;
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@ -57,9 +57,9 @@ function [LIK,lik] = conditional_particle_filter(ReducedForm,Y,start,ParticleOpt
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% AUTHOR(S) frederic DOT karame AT univ DASH lemans DOT fr
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% stephane DOT adjemian AT univ DASH lemans DOT fr
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persistent init_flag mf0 mf1
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persistent init_flag mf1
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persistent number_of_particles
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persistent sample_size number_of_state_variables number_of_observed_variables
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persistent sample_size number_of_observed_variables
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% Set default
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if isempty(start)
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@ -68,10 +68,10 @@ end
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% Set persistent variables.
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if isempty(init_flag)
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mf0 = ReducedForm.mf0;
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%mf0 = ReducedForm.mf0;
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mf1 = ReducedForm.mf1;
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sample_size = size(Y,2);
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number_of_state_variables = length(mf0);
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%number_of_state_variables = length(mf0);
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number_of_observed_variables = length(mf1);
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init_flag = 1;
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number_of_particles = ParticleOptions.number_of_particles ;
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@ -84,14 +84,14 @@ if isempty(H)
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H = 0;
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H_lower_triangular_cholesky = 0;
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else
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H_lower_triangular_cholesky = reduced_rank_cholesky(H)';
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H_lower_triangular_cholesky = chol(H)'; %reduced_rank_cholesky(H)';
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end
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% Get initial condition for the state vector.
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StateVectorMean = ReducedForm.StateVectorMean;
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StateVectorVarianceSquareRoot = reduced_rank_cholesky(ReducedForm.StateVectorVariance)';
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state_variance_rank = size(StateVectorVarianceSquareRoot,2);
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Q_lower_triangular_cholesky = reduced_rank_cholesky(Q)';
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Q_lower_triangular_cholesky = chol(Q)'; %reduced_rank_cholesky(Q)';
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% Set seed for randn().
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set_dynare_seed('default');
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@ -43,9 +43,10 @@ prior = probability2(st_t_1,sqr_Pss_t_t_1,particles) ;
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% likelihood
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yt_t_1_i = measurement_equations(particles,ReducedForm,ThreadsOptions) ;
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eta_t_i = bsxfun(@minus,obs,yt_t_1_i)' ;
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yt_t_1 = sum(yt_t_1_i*weigths1,2) ;
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tmp = bsxfun(@minus,yt_t_1_i,yt_t_1) ;
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Pyy = bsxfun(@times,weigths2',tmp)*tmp' + H ;
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%yt_t_1 = sum(yt_t_1_i*weigths1,2) ;
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%tmp = bsxfun(@minus,yt_t_1_i,yt_t_1) ;
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%Pyy = bsxfun(@times,weigths2',tmp)*tmp' + H ;
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Pyy = H ;
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sqr_det = sqrt(det(Pyy)) ;
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foo = (eta_t_i/Pyy).*eta_t_i ;
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likelihood = exp(-0.5*sum(foo,2))/(normconst*sqr_det) + 1e-99 ;
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@ -118,5 +118,5 @@ else
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StateVectorMean = PredictedStateMean + KalmanFilterGain*PredictionError;
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StateVectorVariance = PredictedStateVariance - KalmanFilterGain*PredictedObservedVariance*KalmanFilterGain';
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StateVectorVariance = .5*(StateVectorVariance+StateVectorVariance');
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StateVectorVarianceSquareRoot = reduced_rank_cholesky(StateVectorVariance)';
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StateVectorVarianceSquareRoot = chol(StateVectorVariance)'; %reduced_rank_cholesky(StateVectorVariance)';
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end
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@ -66,12 +66,12 @@ if isempty(H)
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end
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% Initialization of the likelihood.
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const_lik = log(2*pi)*number_of_observed_variables;
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const_lik = log(2*pi)*number_of_observed_variables +log(det(H)) ;
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lik = NaN(sample_size,1);
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% Get initial condition for the state vector.
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StateVectorMean = ReducedForm.StateVectorMean;
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StateVectorVarianceSquareRoot = reduced_rank_cholesky(ReducedForm.StateVectorVariance)';
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StateVectorVarianceSquareRoot = chol(ReducedForm.StateVectorVariance)';%reduced_rank_cholesky(ReducedForm.StateVectorVariance)';
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if pruning
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StateVectorMean_ = StateVectorMean;
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StateVectorVarianceSquareRoot_ = StateVectorVarianceSquareRoot;
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@ -103,12 +103,13 @@ for t=1:sample_size
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else
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tmp = local_state_space_iteration_2(yhat,epsilon,ghx,ghu,constant,ghxx,ghuu,ghxu,ThreadsOptions.local_state_space_iteration_2);
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end
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PredictedObservedMean = tmp(mf1,:)*transpose(weights);
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%PredictedObservedMean = tmp(mf1,:)*transpose(weights);
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PredictionError = bsxfun(@minus,Y(:,t),tmp(mf1,:));
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dPredictedObservedMean = bsxfun(@minus,tmp(mf1,:),PredictedObservedMean);
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PredictedObservedVariance = bsxfun(@times,dPredictedObservedMean,weights)*dPredictedObservedMean' + H;
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if rcond(PredictedObservedVariance) > 1e-16
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lnw = -.5*(const_lik+log(det(PredictedObservedVariance))+sum(PredictionError.*(PredictedObservedVariance\PredictionError),1));
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%dPredictedObservedMean = bsxfun(@minus,tmp(mf1,:),PredictedObservedMean);
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%PredictedObservedVariance = bsxfun(@times,dPredictedObservedMean,weights)*dPredictedObservedMean' + H;
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%PredictedObservedVariance = H;
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if rcond(H) > 1e-16
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lnw = -.5*(const_lik+sum(PredictionError.*(H\PredictionError),1));
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else
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LIK = NaN;
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return
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