Module auxiliary_grid 

Auxiliary energy grid construction for resolution broadening.

SAMMY extends the energy grid before computing cross-sections and applying broadening. This module reproduces SAMMY’s default grid construction:

1. Boundary extension (Eqcon/Vqcon): Extend below E_min and above E_max using spacing of the first/last 5 data points, uniform in √E (FGM Doppler convention).
2. Resonance fine-structure (Fspken/Add_Pnts): Add dense points around narrow resonances where the existing grid has fewer than 10 points per resonance width (SAMMY default iptdop=9).
3. Intermediate points (Eqxtra): Insert extra points between each pair. Default is 0 — none of our test cases override this.

SAMMY Reference

• dat/mdat4.f90 — Escale (main entry), Fspken (resonance scan), Add_Pnts (fine-structure insertion)
• dat/mdata.f90 — Eqxtra (intermediate points), Eqcon/Vqcon (boundary extension)
• inp/InputInfoData.cpp — Default iptdop=9, iptwid=5, nxtra=0

Functions

build_extended_grid

Build an extended energy grid with boundary extension and resonance fine-structure for resolution broadening.

build_extended_grid_boundary_only

Build extended grid with boundary extension only (no intermediate points).