Python API

The sid package exposes 19 public functions and 8 result dataclasses from its top-level namespace. Every function maps 1:1 to a MATLAB equivalent — see the function index for the pairing table.

Frequency-domain estimators

• freq_bt — Blackman-Tukey spectral analysis
• freq_btfdr — Blackman-Tukey with frequency-dependent resolution
• freq_etfe — Empirical transfer function estimate
• freq_map — Time-varying frequency map
• spectrogram — Sliding-window spectrogram

State-space identification

• ltv_disc — COSMIC LTV state-space identification
• ltv_disc_io — Output-COSMIC (output-only identification)
• ltv_disc_tune — Automatic regularization tuning
• ltv_disc_frozen — Frozen-time transfer functions G(ω, k)
• lti_freq_io — LTI frequency response from input/output data
• ltv_state_est — RTS-smoother state estimation
• model_order — Model order selection

Analysis

• compare — Model comparison metrics
• detrend — Detrending utilities
• residual — Residual diagnostics

Plotting

• bode_plot — Bode plots from FreqResult
• spectrum_plot — Power spectrum plots
• map_plot — Time-frequency map plots
• spectrogram_plot — Spectrogram plots

Result types

• Result dataclasses — FreqResult, LTVResult, etc.