Emit Code Cards

Nucleide renders one material through five legacy transport-code dialects — MCNP, Serpent, FLUKA, ALARA, PARTISN — and reports how much mass survives each translation. This tutorial shows the Python API; equivalent Rust types live in the emit crate.

Cards for all five codes

from nucleide import emit

comp = {"U235": 5.0, "U238": 95.0}
cards = emit.emit_cards(comp, "umetal", density=19.1)
print(sorted(cards))
print(cards["MCNP"])

The MCNP card uses mass fractions with a configurable library suffix, the Serpent card uses {zaid}.{lib} ids, and long MCNP cards wrap within the 128-column limit:

print(cards["Serpent"])
print(cards["ALARA"])

Mass-drift report

emit_drift_table returns one row per dialect with the represented mass, the relative drift (the fraction of the input mass the dialect’s text could not represent), dropped nuclides with reasons, and whether the text was re-parse verified (MCNP and ALARA only):

rows = emit.emit_drift_table(comp, "umetal", density=19.1)
for row in rows:
    print(row["code"], row["rel_drift"], row["dropped"], row["reparsed"])

Nuclides a dialect cannot represent — O16 has no FLUKA isotope-table entry — show up as reported drift instead of silent loss:

rows = emit.emit_drift_table({"U235": 1.0, "O16": 2.0}, "uox", density=10.0)
fluka = next(r for r in rows if r["code"] == "FLUKA")
print(fluka["mass_out"], fluka["dropped"])

ARMI blueprint keys

emit_armi_cards / emit_armi_drift_table accept ARMI-side mass-fraction dicts — database names (nU235), ZAIDs (92235), AAAZZZS ids, and unambiguous MC2-3 labels (U-2355, U235_7) — and emit the same five cards as GNDS names:

armi_cards = emit.emit_armi_cards({"nU235": 5.0, "nU238": 95.0}, "umetal", density=19.1)
assert armi_cards == emit.emit_cards({"U235": 5.0, "U238": 95.0}, "umetal", density=19.1)

The bridge is one-way (dict in, never ARMI YAML or .h5) and keeps ARMI-side resolution with the caller:

Pass post-expansion nuclide fractions (material.massFrac). Elemental keys (ZR, FE, O, …) are rejected with an “expand first” error.
Values are masses in grams; number fractions/densities must be converted first. Enrichment shorthands, balance, and temperatures are resolved by the caller, which passes the hot density in g/cm³ (None keeps the usual MissingDensity behavior for Serpent/FLUKA/PARTISN).
Bare AM242 is rejected as ambiguous — pass AM242M for Am-242m or AM242G for ground explicitly.