**Subsections**

##

n_state_model.select_model

Select the N-state model type and set up the model.

n_state_model.select_model(model=`population')

model: The name of the preset N-state model.

Prior to optimisation, the N-state model type should be selected. The preset models are:

**`population' -**
- The N-state model whereby only populations are optimised. The structures loaded into relax are assumed to be fixed,
*i*.e. the orientations are not optimised, or if two domains are present the Euler angles for each state are fixed. The parameters of the model include the weight or probability for each state and the alignment tensors - {p0, p1, ..., pN, Axx, Ayy, Axy, Axz, Ayz, ...}.
**`fixed' -**
- The N-state model whereby all motions are fixed and all populations are fixed to the set probabilities. The parameters of the model are simply the parameters of each alignment tensor {Axx, Ayy, Axy, Axz, Ayz, ...}.
**`2-domain' -**
- The N-state model for a system of two domains, where one domain experiences a reduced tensor.

To analyse populations of states, type:

[numbers=none]
relax> n_state_model.select_model(model='populations')

The relax user manual (PDF), created 2019-06-14.