Forward Model ============= Boundary -------- ``euclid_dsps.model`` is the only native DSPS boundary. MAP, MCLMC, synthetic-closure generation, and amortized inference all pass through the same theta-vector and model-evaluation contract. FENIKS Closure Model -------------------- The active FENIKS closure configs use the 18D ``diffsky_basic`` parameter vector: .. code-block:: text z_obs log10_stellar_mass diffstar_lgmcrit diffstar_lgy_at_mcrit diffstar_indx_lo diffstar_indx_hi diffstar_lg_qt diffstar_qlglgdt diffstar_lg_drop diffstar_lg_rejuv diffmah_logm0 diffmah_logtc diffmah_early_index diffmah_late_index diffmah_t_peak log10_stellar_metallicity dust_av dust_delta The 14-band production setup uses: .. code-block:: text LSST u,g,r,i,z,y + Roman F062,F087,F106,F129,F146,F158,F184,F213 During generation, FENIKS truths are decoded with local DSPS to write ``flux_true_``. The configured ``m5_depth`` error model then writes ``fluxerr_`` and noisy ``flux_``. Validation recomputes the true fluxes from the stored truth vector. FS2 Comparison Model -------------------- ``configs/fs2_gpu.yaml`` keeps the Euclid comparison path. It uses ten bands: .. code-block:: text LSST u,g,r,i,z,y + Euclid VIS,Y,J,H and a 16-parameter PopCosmos-like vector with compressed stellar, gas, and AGN assets. FS2 is useful for comparison and regression checks, not for defining the FENIKS learned-prior target. HLTDS Debug Model ----------------- The active HLTDS configs are dataset/download configs, not MAP experiment configs. They preserve the low-z HLTDS photometry, error model, provenance, and projected-truth fields so that FENIKS can be compared to an external reference. SSP Assets ---------- FENIKS and HLTDS use the HLTDS SSP assets: .. code-block:: text Data/diffsky/raw/hltds_cosmos_260215_04_14_2026/diffsky_hltds_cosmos_260215_04_14_2026_ssp_data.hdf5 Data/diffsky/raw/hltds_cosmos_260215_04_14_2026/diffsky_hltds_cosmos_260215_04_14_2026_ssp_basis_k64_coeff16.hdf5 FS2 uses the local compressed FSPS assets: .. code-block:: text Data/popcosmos_chabrier_stellar_ssp_basis_k64_coeff16.h5 Data/popcosmos_chabrier_gas_grid_basis_k64_mixed16.h5 Data/popcosmos_chabrier_agn_component_basis_k12_fagnlinear_coeff16.h5 Likelihoods ----------- The active configs use flux-space Student-t likelihoods with explicit ``fluxerr_*`` columns plus configured fractional floors. For FENIKS, the error columns are generated by the closure pipeline and are part of the controlled dataset contract. For HLTDS, the error columns are materialized during dataset preparation and should be treated as debug/reference metadata.