Line-Selection Reference

Line-Selection Reference#

This page is the parameter reference for PySME line selection and line-info precomputation. It complements Line Filtering, which focuses more on workflow and examples.

Mental model#

Line selection in PySME is controlled in three layers:

  1. linelist_mode

    • all: synthesize with the full line list

    • dynamic: synthesize with a per-segment filtered subset

    • auto: deprecated alias of dynamic

  2. line_select_method

    • internal: no external CDR/ALMAX metadata path

    • cdr: use central_depth and line_range_*

    • almax: use almax_ratio and line_range_*

  3. line_select_policy

    • auto: use method-dependent automatic line-info handling

    • strict: require explicit method-specific line-info handling

In practice:

  • linelist_mode decides whether dynamic filtering is used

  • line_select_method decides how line metadata is generated/interpreted

  • line_select_policy decides how strictly that metadata is enforced

Shared parameters#

linelist_mode#

Function argument in solve(...) and synthesize_spectrum(...).

  • all: use the full line list

  • dynamic: use dynamic line filtering

  • auto: deprecated alias of dynamic

sme.line_select_method#

  • internal

  • cdr

  • almax

Controls which metadata path is used for line preselection.

sme.line_select_policy#

  • auto

  • strict

Controls how method-specific line metadata is consumed by the synthesis path.

sme.line_select_parallel#

Boolean. Enable or disable parallel metadata updates.

sme.line_select_n_jobs#

Worker count for parallel metadata updates.

  • None: infer automatically

  • positive integer: explicit worker count

sme.line_select_chunk_size#

Chunk size used when splitting the line list for metadata updates.

sme.line_select_recompute#

  • if_stale: recompute line metadata only when missing or stale

  • always: recompute every time

  • never: do not recompute; require existing metadata or cache entries

This is the main control for metadata regeneration.

sme.line_select_stale_thres#

Dictionary of stale thresholds, typically including:

  • teff

  • logg

  • monh

  • vmic

  • accrt

Used to decide whether previously computed metadata is still valid.

sme.line_precompute_database#

Preferred cache-directory parameter.

This is the shared on-disk cache for line precompute products from both cdr and almax.

CDR-specific parameters#

sme.line_select_cdr_strength_thres#

Threshold for strong-line selection in CDR mode.

sme.line_select_cdr_bin_width#

Bin width used in CDR strong-line selection.

CDR currently uses the bin-based strong-line helper directly, so there is no separate cdr_use_bins switch.

ALMAX-specific parameters#

sme.line_select_almax_threshold#

Threshold used by ALMAX-based selection.

If None, it falls back to sme.accrt.

sme.line_select_almax_use_bins#

Boolean switch controlling which ALMAX strong-line rule is used:

  • False: simple threshold rule using almax_ratio >= line_select_almax_threshold

  • True: bin-wise cumulative rule using flag_strong_lines_by_bins(...)

sme.line_select_almax_bin_width#

Bin width used when line_select_almax_use_bins=True.

Deprecated or legacy parameters#

These are still accepted for backward compatibility, but should not be used in new code.

cdr_database#

Deprecated alias of line_precompute_database.

sme.cdr_N_line_chunk#

Legacy alias of sme.line_select_chunk_size.

sme.cdr_parallel#

Legacy alias of sme.line_select_parallel.

sme.cdr_n_jobs#

Legacy alias of sme.line_select_n_jobs.

sme.strong_depth_thres#

Legacy alias of sme.line_select_cdr_strength_thres.

sme.strong_bin_width#

Legacy compatibility field for bin-width based strong-line selection. Prefer:

  • sme.line_select_cdr_bin_width

  • sme.line_select_almax_bin_width

sme.line_select_reuse#

Deprecated.

Non-default values currently only trigger a limited internal reuse path by keeping line opacity around. This is not a fully developed or stable public cache policy, and new code should leave it at the default none.

cdr_create#

Legacy-style function argument still used to force regeneration of cached line metadata products. It remains supported, but is not yet replaced by a clearer unified name.

See also#

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