# trajsimil.m

From Spinach Documentation Wiki

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.

## Contents

## 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.

## See also

trajan.m, basis.m, evolution.m, krylov.m

*Version 2.2, authors: Ilya Kuprov, Konstantin Pervushin*