Dead code: src/dedx_const.h is never included and its constants are unused

[grzanka]

Summary

src/dedx_const.h defines a set of physics constants but the header is not included by any translation unit, and none of the macros it defines are referenced anywhere in src/ or include/. It is effectively dead code.

Details

The header defines:

#define DEDX_N_AVO   6.0221367
#define DEDX_AMU     931.49432
#define DEDX_PI      3.14159265358979323846
#define DEDX_EMASS   0.51099906
#define DEDX_ECHARGE 1.60217733
#define DEDX_ECHARGE2 14.399652

Evidence:

• grep -rln 'dedx_const.h' src include → matches only the file itself (no #include "dedx_const.h" anywhere).
• grep -rn 'DEDX_N_AVO\|DEDX_AMU\|DEDX_EMASS\|DEDX_ECHARGE' src include (excluding the header itself) → no matches.

So either:

1. The header is stale and should be removed, or
2. These constants are duplicated as magic numbers in the .c files (Bethe / mpaul / mstar computations) and the intent was to centralize them here.

Suggested action

Confirm which case applies:

• If the constants are unused → delete src/dedx_const.h.
• If equivalent magic numbers exist in the .c files → wire the header in and replace the literals, so the constants live in one place.

Notes

This was found during a dependency-structure review of libdedx. The overall include graph is otherwise clean (no circular dependencies, consistent and unique include guards, good public/private header separation). A few other smaller items were noted separately (e.g. static const arrays defined in dedx_periodic_table.h); this issue is scoped to the dedx_const.h dead code only.