# Enum: CouplingStageEvaluation 




_How the network coupling term is evaluated within one step of a multi-stage integrator (Heun, RK4, ...). A backend-neutral numerical contract: whether the coupling is part of the vector field, re-evaluated at each solver stage, or computed once per step and held constant across the stages. Matters because the two choices integrate a different effective system — for stiff / chaotic / multistable dynamics they can converge to different trajectories or attractors._



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URI: [tvbo:enum/CouplingStageEvaluation](https://w3id.org/tvbo/enum/CouplingStageEvaluation)

## Permissible Values
| Value | Meaning | Description |
| --- | --- | --- |
| per_stage | None | Re-evaluate the coupling at every integrator stage — the coupling is a full p... |
| per_step | None | Evaluate the coupling once per integration step and hold it constant across t... |




## Slots

| Name | Description |
| ---  | --- |
| [coupling_evaluation](../slots/coupling_evaluation.qmd) | Backend-neutral numerical treatment of the network coupling term across the s... |










## Identifier and Mapping Information





### Schema Source


* from schema: https://w3id.org/tvbo






## LinkML Source

<details>
```yaml
name: CouplingStageEvaluation
description: 'How the network coupling term is evaluated within one step of a multi-stage
  integrator (Heun, RK4, ...). A backend-neutral numerical contract: whether the coupling
  is part of the vector field, re-evaluated at each solver stage, or computed once
  per step and held constant across the stages. Matters because the two choices integrate
  a different effective system — for stiff / chaotic / multistable dynamics they can
  converge to different trajectories or attractors.'
from_schema: https://w3id.org/tvbo
rank: 1000
permissible_values:
  per_stage:
    text: per_stage
    description: Re-evaluate the coupling at every integrator stage — the coupling
      is a full part of the vector field (standard ODE integration). Accurate; required
      to reproduce reference integrators for stiff / chaotic / multistable systems.
      (tvboptim maps this to recompute_coupling_per_stage=True; diffrax already recomputes
      the whole RHS per stage.)
  per_step:
    text: per_step
    description: 'Evaluate the coupling once per integration step and hold it constant
      across the stages — a TVB-style efficiency shortcut (the coupling reduction
      runs once per step). Faster but lower- order in the coupling; can change the
      trajectory for sensitive systems. (tvboptim: recompute_coupling_per_stage=False,
      the current backend default.)'

```
</details>

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