Zte.m

Zero track elimination function. Inspects the first few steps in the system trajectory and drops the states that did not get populated to a user-specified tolerance.

Syntax

    projector=zte(spin_system,L,rho,nstates)

Arguments

     L       - the Liouvillian to be used for time 
               propagation

     rho     - the initial state to be used for 
               time propagation
 
     nstates - if this parameter is specified, only
               nstates most populated states are kept,
               irrespective of the tolerance parameter

Outputs

     projector - projector matrix into the reduced space,
                 to be used as follows: 

                           L_reduced=P'*L*P
                           rho_reduced=P'*rho;

Notes

1. Default tolerance may be altered by setting sys.tols.zte_tol variable before calling create.m
2. Further information on how this function works is available in IK's JMR paper on the subject, see http://dx.doi.org/10.1016/j.jmr.2008.08.008
3. If tiny interactions or nearly equivalent spins are present, it is best to disable zero track elimination by adding 'zte' to the sys.disable cell array.

See also

reduce.m, path_trace.m, symmetry.m, krylov.m

Version 2.2, authors: Ilya Kuprov