# trajsimil.m

Computes trajectory similarity scores. Returns a function representing "similarity" of the two state space trajectories at different points in time. See http://dx.doi.org/10.1016/j.jmr.2013.02.012 for further information.

## Syntax

    trajsimil(spin_system,trajectory_1,trajectory_2,method)


## Arguments

  trajectory_1,2 - spin system trajectories, supplied as nstates
x nsteps matrices.

method         - similarity scoring method; possibilities are:

'RSP'  - running scalar product. Computes
scalar products between the cor-
responding vectors of the trajec-
tories.

'RDN'  - running difference norm. The two
trajectories are subtracted and
difference 2-norms returned.

'SG-'  - prefix that turns on state grou-
ping. T(l,m) and T(l,-m) states
of each spin (standalone or in
direct products with other ope-
rators)will be considered equva-
lent.

'BSG-' - prefix that turns on broad state
grouping. All states of a given
spin (standalone or in direct
products with other operators)
will be considered equivalent.

The possible combinations are: 'RSP','RDN',
'SG-RSP','SG-RDN','BSG-RSP','BSG-RDN'.


State grouping consists in summing the absolute squares of the coefficients to be grouped and taking the square root. The trajectories would usually come out of the evolution.m or krylov.m run from a given starting point under a given Liouvillian.

## Outputs

    This function writes into the current figure.


## Examples

Figure 6 of http://dx.doi.org/10.1016/j.jmr.2013.02.012 was created using this function.

## Notes

SG and BSG options require sphten-liouv formalism.