Avoid repeated temporary allocations during compartment reconstruction in flow-based simulations

[HenrZu]

Motivation / Current Behaviour

Flow-based simulations repeatedly evaluate the difference between the current cumulative flows and the flows at the most recent base point. This expression currently creates a temporary dynamically sized vector during every RHS evaluation and again when compartment outputs are reconstructed.

A reusable flow-difference vector should be allocated once per simulation and used for both right-hand-side evaluations and compartment reconstruction.

Enhancement description

This does not change the numerical formulation or simulation results.

Additional context

No response

Checklist

• Attached labels, especially loc:: or model:: labels.
• Linked to project