fix bug in diffuse smoother with algo=3. rank of PINF should be checked...
fix bug in diffuse smoother with algo=3. rank of PINF should be checked towards observables, as for kalman algo 4 and kalman_filter_d
fix bug in diffuse smoother with algo=3. rank of PINF should be checked towards observables, as for kalman algo 4 and kalman_filter_d