WannierIO.jl

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Read and write files ​

WannierIO follows a consistent IO pattern across Wannier90 formats:

  1. read with a read_* function,

  2. if needed, modify the returned Julia data,

  3. write back with the matching write_* function.

IO conventions ​

  • Function pairs are usually named read_xxx and write_xxx.

  • Most readers/writers accept a filename or an IO stream.

  • For several Wannier90 files, writing supports binary=true to emit Fortran unformatted files.

  • Tight-binding files additionally support backend formats (HDF5/JLD2/Zarr) via read_w90_tb and write_w90_tb.

Common workflows ​

1. Round-trip a plain-text Wannier90 file ​

julia
using WannierIO

amn = read_amn("silicon.amn")
write_amn("silicon_copy.amn", amn.A; header=amn.header)

The same pattern applies to other files such as read_mmn/write_mmn, read_eig/write_eig, and read_nnkp/write_nnkp.

2. Write Fortran binary files ​

julia
using WannierIO

chk = read_chk("silicon.chk")
write_chk("silicon_binary.chk", chk; binary=true)

spn = read_spn("silicon.spn")
write_spn("silicon_binary.spn", spn; binary=true)

This is useful when interoperating with workflows that expect native Fortran unformatted output.

3. Work with win input files ​

julia
using WannierIO

win = read_win("silicon.win")
win["num_iter"] = 200
write_win("silicon_new.win", win)

read_win can parse both text and TOML-style inputs via format detection.

4. Read and write tight-binding files ​

julia
using WannierIO

# High-level API with automatic wsvec handling when available.
pack = read_w90_tb("silicon_tb.dat")
write_w90_tb("silicon_out_tb.dat", pack)

For details on reduction and sparse backends, see Tight-binding operators and Sparse storage.

5. Volumetric data formats ​

julia
using WannierIO

xsf = read_xsf("charge.xsf")
write_xsf("charge_copy.xsf", xsf)

cube = read_cube("density.cube")
write_cube("density_copy.cube", cube)

Supported volumetric formats include XSF, CUBE, and BXSF.

Tips ​

  • Preserve metadata fields (for example headers/lattice metadata) when writing modified data.

  • If you rely on binary files, test round-trip compatibility on your target compiler/platform because unformatted Fortran records are not universally portable.

  • Prefer high-level helpers like read_w90_tb unless you explicitly need low-level file-to-file control.

For a deeper API-level reference, see Wannier90 and Tight binding.