Parse MCNP Output

Nucleide reads several common MCNP-family files without running MCNP itself. This tutorial shows the Python API; equivalent Rust types live in the mcnp-io crate.

xsdir

An xsdir file indexes the cross-section tables available to MCNP.

from nucleide.mcnp import read_xsdir

xs = read_xsdir("path/to/xsdir")
print(xs.datapath)
for t in xs.tables[:5]:
    print(t.name, t.zaid())

meshtal

A meshtal file contains one or more FMESH tallies.

from nucleide.mcnp import read_meshtal

mt = read_meshtal("path/to/meshtal")
print(mt.version, mt.histories)

t4 = mt.tallies[4]
print(t4.dims(), t4.num_ves())

MCTAL, WWINP, PTRAC, and SSW

from nucleide.mcnp import read_mctal, read_ptrac, read_ssw, read_wwinp

k = read_mctal("path/to/mctal")
ww = read_wwinp("path/to/wwinp")
pt = read_ptrac("path/to/ptrac")
ss = read_ssw("path/to/ssw")

Writing SSW files

Use write_ssw to write a modified surface-source file back to disk.

from nucleide.mcnp import write_ssw

write_ssw(ss, "path/to/output.ssw")

Fixtures

Golden-byte reference files live under fixtures/mcnp/. Tests assert that Nucleide reproduces them byte-for-byte where parity is intended.