Input and Output

save_code(path, code; type=...) is the common export entry point. The type keyword is a symbol and dispatches through Val(type). If it is omitted, the format is inferred from the filename when possible.

Matrix CSV

CSV stores one integer matrix and is intended for interchange with numerical tools:

using Oscar
using CodingTheory

C = HammingCode(2, 3)
save_code("hamming.csv", C; type=:csv)

Classical codes export their generator matrix by default. Use code_matrix_array(C; representation=:parity_check) when selecting a matrix explicitly. LDPC codes default to their parity-check presentation.

For a quantum code, CSV contains its additive generator matrix:

F = GF(2)
H = matrix(F, [
    0 0 0 1 1 1 1
    0 1 1 0 0 1 1
    1 0 1 0 1 0 1
])
S = CSSCode(H, H)
save_code("steane.csv", S)

CSV is not a lossless code format: it does not preserve the field, character-vector phases, sparse preference, code subtype, or cached results.

Portable quantum TOML

TOML is the portable, versioned quantum-code format:

save_code("steane.toml", S; type=:toml)
restored = load_quantum_code("steane.toml")

It preserves the base field, additive generators, character vector, sparse preference, and validated cache entries. Set restore_cache=false when loading data from an untrusted or incompatible computation.

The dictionary representation is available directly:

data = quantum_code_data(S)
restored = quantum_code_from_data(data)

Pauli strings

Binary phase-free stabilizer presentations can be exchanged as one Pauli string per line:

write_pauli_strings("steane.pauli", S)
restored = read_pauli_strings("steane.pauli")

Use pauli_strings(S) when an in-memory vector is sufficient. Explicitly phased codes are rejected rather than silently losing phase information.

Optional binary formats

JLD2 and NumPy NPZ support are package extensions. Load the corresponding package before requesting the format:

using JLD2
save_code("code.jld2", S; type=:jld2)

using NPZ
save_code("code.npz", S; type=:npz)

If an optional dependency is not loaded, save_code reports which package is required.