133 lines
3.5 KiB
Matlab
133 lines
3.5 KiB
Matlab
function [flag] = compare_kalman_mex(experience)
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rng(experience.Seed);
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N = experience.NumberOfSimulations;
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pp = experience.Number0fObservedVariables*experience.Scale;
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mm = experience.SizeOfTheStateVector*experience.Scale;
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rr = experience.NumberOfStructuralShocks*experience.Scale;
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measurement_error_flag = experience.MeasurementErrors;
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gend = experience.NumberOfPeriods;
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%% SET VARIOUS PARAMETERS
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kalman_tol = 1e-12;
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riccati_tol =1e-9;
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%% SET THE STATE SPACE MODEL:
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% I randomly choose the mm eigenvalues of the transition matrix.
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TransitionEigenvalues = rand(mm, 1)*2-1;
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% I randomly choose the mm eigenvectors of the transition matrix
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TransitionEigenvectors = rand(mm, mm);
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% I build the transition matrix
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T = TransitionEigenvectors*diag(TransitionEigenvalues)/TransitionEigenvectors;
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% I randomly choose matrix R
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R = randn(mm, rr);
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% I randomly choose the covariance matrix of the structural innovations
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E = randn(rr, 20*rr);
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Q = E*transpose(E)/(20*rr);
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% If needed I randomly choose the covariance matrix of the measurement errors
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if measurement_error_flag == 0
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H = zeros(pp,1);
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elseif measurement_error_flag == 1
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H = rand(pp,1);
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elseif measurement_error_flag == 2
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E = randn(pp,20*pp);
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H = E*transpose(E)/(20*pp);
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H = (.1*eye(pp))*H*(.1*eye(pp));
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else
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disp('compare_kalman_mex: unknown option!')
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end
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% Set the selection vector (mf)
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MF = transpose(randperm(mm));
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mf = MF(1:pp);
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% Compute ergodic variance of the state equation
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P = lyapunov_symm(T,R*Q*R',riccati_tol,1.000001, riccati_tol);
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if measurement_error_flag==0
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HH = [];
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elseif measurement_error_flag==1
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HH = diag(H);
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elseif measurement_error_flag==2
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HH = H;
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end
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rng(experience.Seed*1938);
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% Build datasets
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Y = simul_state_space_model(T,R,Q,mf,gend*N, HH);
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if isempty(HH)
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HH = 0;
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end
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%
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% Evaluate likelihoods
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%
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LIK_matlab_0 = NaN(N,1);
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LIK_mex_0 = NaN(N,1);
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flag = 0;
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Zflag = 0;
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tic;
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for i=1:N
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[LIK_matlab_0(i), ~] = kalman_filter(Y(:,(i-1)*gend+1:i*gend),1,gend,zeros(mm,1),P,kalman_tol,riccati_tol,0,0,T,Q,R,HH,mf,mm,pp,rr,Zflag,0,0);
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end
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T_matlab_0 = toc;
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tic;
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for i=1:N
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[LIK_mex_0(i), ~] = kalman_filter_mex(Y(:,(i-1)*gend+1:i*gend),zeros(mm,1),P,kalman_tol,riccati_tol,T,Q,R,mf,Zflag,HH);
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end
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T_mex_0 = toc;
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dprintf('Zflag = 0: Fortran Kalman filter is %5.2f times faster than its Matlab counterpart.', T_matlab_0/T_mex_0)
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if max(abs((LIK_mex_0-LIK_matlab_0)./LIK_matlab_0))>1e-6
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dprintf("Zflag = 0: discrepancy between Matlab and Fortran Kalman filter results!")
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flag = 1;
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end
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LIK_matlab_1 = NaN(N,1);
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LIK_mex_1 = NaN(N,1);
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Zflag = 1;
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Z = eye(mm);
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Z = Z(mf,:);
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tic;
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for i=1:N
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[LIK_matlab_1(i), ~] = kalman_filter(Y(:,(i-1)*gend+1:i*gend),1,gend,zeros(mm,1),P,kalman_tol,riccati_tol,0,0,T,Q,R,HH,Z,mm,pp,rr,Zflag,0,0);
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end
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T_matlab_1 = toc;
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tic;
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for i=1:N
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[LIK_mex_1(i), ~] = kalman_filter_mex(Y(:,(i-1)*gend+1:i*gend),zeros(mm,1),P,kalman_tol,riccati_tol,T,Q,R,Z,Zflag,HH);
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end
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T_mex_1 = toc;
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dprintf('Zflag = 1: Fortran Kalman filter is %5.2f times faster than its Matlab counterpart.', T_matlab_1/T_mex_1)
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if max(abs((LIK_mex_1-LIK_matlab_1)./LIK_matlab_1))>1e-6
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dprintf("Zflag = 1: discrepancy between Matlab and Fortran Kalman filter results!")
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flag = 1;
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end
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if max(abs((LIK_mex_0 - LIK_mex_1)./LIK_mex_1))>1e-6
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dprintf("Zflag = 1: discrepancy between results with and without the Zflag!")
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flag = 1;
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end
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dprintf('Cost of Zflag==1 is %5.2f%% (matlab)', 100*(T_matlab_1-T_matlab_0)/T_matlab_0)
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dprintf('Cost of Zflag==1 is %5.2f%% (mex)', 100*(T_mex_1-T_mex_0)/T_mex_0)
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