sqq 0.1.3

Shell Quant Qualifier for water-shell topology analysis in MD trajectories.

SQQ

SQQ: Python Joint Toolkit for Water-Shell Topology Analysis.

SQQ builds a water network, finds rings, standard half-cages, quasi-cages, closed cages, cage guest occupancy, F3/F4 metrics, and ice-like waters. Detailed algorithms are documented in docs/design.md; version notes are documented in docs/update.md.

Install

Install the released package from PyPI:

pip install sqq

Upgrade an existing installation:

pip install -U sqq

For local development from a source checkout:

pip install -e .

Then use:

sqq -h
sqq init -o config.yaml
sqq analyze -i ./gro -c config.yaml -o ./result_sqq

During source-tree development without installation:

python -m sqq analyze -i ./gro -c config.yaml -o ./result_sqq

Quick Start

Single GRO file:

sqq analyze -i test1.gro -o ./result_sqq

Directory of GRO files:

sqq analyze -i ./gro --pattern "*.gro" -o ./result_sqq

Glob pattern:

sqq analyze -i "./gro/*.gro" -o ./result_sqq

XTC/TRR trajectory with a topology file:

sqq analyze -i traj.xtc --top topol.gro -c config.yaml -o ./result_sqq

Analysis Modes

-m / --mode selects one of three base presets:

Mode	Purpose	Water graph	Ring/cage sizes	Other cages	Automatic workers
00	Rigorous	Hydrogen bond	4, 5, 6	Enabled	25% of logical CPUs
50	Standard (default)	Auto	5, 6	Disabled	50% of logical CPUs
99	Performance screening	O-O connectivity	5, 6	Disabled	90% of logical CPUs

sqq analyze -i ./gro -m 00 -o ./result_rigorous
sqq analyze -i ./gro -m 50 -o ./result_standard
sqq analyze -i ./gro -m 99 -o ./result_performance

Modes do not change quasi_cage.max_layers; L1 remains the default in every mode. Use --quasi-max-layers explicitly for L2/L3. Automatic workers are capped by the number of independent GRO/XYZ files. A single coordinate file or XTC/TRR trajectory still runs with one worker. --workers N overrides the mode percentage.

Common Commands

Write a default configuration file:

sqq init -o config.yaml

Analyze 4/5/6 rings, quasi-cages, and cages:

sqq analyze -i md.gro -s 4,5,6 -o ./result_sqq_456

Enable outer quasi-cage layers:

sqq analyze -i md.gro --quasi-max-layers 3 -o ./result_sqq_l3

Disable per-frame info or structure GRO output:

sqq analyze -i md.gro --no-info -o ./result_sqq_no_info
sqq analyze -i md.gro --no-gro -o ./result_sqq_report

Parallelize independent GRO/XYZ files:

sqq analyze -i ./gro --pattern "*.gro" --workers 4 -o ./result_sqq

Important Defaults

mode: "50"

graph:
  bond_mode: auto
  oo_cutoff_nm: 0.35
  hbond_distance_nm: 0.35
  hbond_angle_deg: 30.0

ring:
  sizes: [5, 6]
  chordless: true

quasi_cage:
  enabled: true
  base_sizes: auto
  side_sizes: auto
  max_layers: 1

cage:
  enabled: true
  ring_sizes: [5, 6]
  target_types: [512, 51262, 51263, 51264]
  output_other: false
  search_mode: grow
  seed_mode: ring
  occupancy_mode: polyhedron

output:
  write_info: true
  write_gro: true
  write_xlsx_summary: true
  structure_layout: grouped

parallel:
  workers: auto

Configuration priority:

built-in defaults < mode preset < config.yaml < explicit command-line options

Useful Options

Option	Possible values	Meaning
-i, --input INPUT	GRO/XYZ/XTC/TRR file, directory, or glob	Input coordinate file or trajectory source
-c, --config FILE	YAML or JSON file	User configuration file
-o, --output DIR	Directory path	Output directory
-m, --mode MODE	00, 50, 99	Select rigorous, standard, or performance preset
-b, --bond-mode MODE	auto, hbond, oo, pairs	Override the water-graph connection mode
-s, --sizes SIZES	Comma-separated 4,5,6 subset	Set ring, quasi-cage, and cage face sizes together
--pattern PATTERN	Glob such as *.gro	File pattern for directory input
--top FILE.gro	GRO topology file	Topology/structure file for XTC/TRR input
--recursive	Flag: present or omitted	Search input directories recursively
--ring-sizes SIZES	Comma-separated 4,5,6,7 subset	Override only ring search sizes
--quasi-sizes SIZES	Comma-separated 4,5,6,7 subset	Override quasi-cage base and side sizes together
--quasi-base-sizes SIZES	Comma-separated 4,5,6,7 subset	Override quasi-cage base-ring sizes
--quasi-side-sizes SIZES	Comma-separated 4,5,6,7 subset	Override quasi-cage side-ring sizes
--quasi-max-layers N	Positive integer; 1-3 documented	Report quasi-cage layers up to N; default is 1
--cage-sizes SIZES	Comma-separated 4,5,6 subset	Override cage face sizes
--other-cages	Flag: present or omitted	Include generated unconventional cages
--no-other-cages	Flag: present or omitted	Disable generated unconventional cages
--other-max-faces N	Positive integer	Maximum face count for unconventional cages
--pairs FILE	Text pair-map file	Supply explicit water-network edges and enable pairs mode
--pair-id KIND	resid, atomid, oxygen_index	Select the identifier type used in the pair file
--workers N	auto or positive integer	Override the mode-based automatic worker count
--strict	Flag: present or omitted	Stop on the first failed frame
--output-layout LAYOUT	grouped, flat	Select the per-frame structure-file layout
--no-info	Flag: present or omitted	Disable per-frame *_info.md files
--no-gro	Flag: present or omitted	Disable all structure GRO files
--no-ring-gro	Flag: present or omitted	Disable ring GRO files
--no-half-cage-gro	Flag: present or omitted	Disable half-cage GRO files
--no-quasi-cage-gro	Flag: present or omitted	Disable quasi-cage GRO files
--no-cage-gro	Flag: present or omitted	Disable cage GRO files
--no-ice-gro	Flag: present or omitted	Disable ice GRO files
--no-xlsx	Flag: present or omitted	Disable summary.xlsx

Bond Mode

Use -b / --bond-mode to override the graph setting supplied by the selected mode or config.yaml:

sqq analyze -i md.gro -b auto
sqq analyze -i md.gro --bond-mode hbond
sqq analyze -i md.gro -b oo
sqq analyze -i md.gro -b pairs --pairs pairs.txt

Available values are auto, hbond, oo, and pairs. --pairs PAIRS.txt used alone remains shorthand for pairs mode. Combining --pairs with -b auto, -b hbond, or -b oo is rejected. Pairs mode requires either --pairs or graph.pair_file in config.yaml.

Output Structure

SQQ writes one folder per frame plus a global workbook:

result_sqq/
  summary.xlsx
  run_config.yaml
  test1/
    test1_info.md
    ring/
      test1_ring_5.gro
      test1_ring_6.gro
    half_cage/
      hc_5r_5^5/
        test1_hc_5r_5^5.gro
    quasi_cage/
      qc_5r_5^3-6^2_55566/
        test1_qc_5r_5^3-6^2_55566.gro
    cage/
      5^12/
        test1_cage_5^12.gro
        test1_cage_5^12_empty.gro
        test1_cage_5^12_occupied.gro
    ice/
      test1_ice.gro

Output ownership is:

cage > quasi_cage > half_cage > ring

Cage files include cage waters, CNT center atoms, and assigned guests. Exact guest-composition files are generated from the guest names present in the frame, such as CH4, CH4x2, or CH4+CO2.

See docs/design.md for algorithm details and docs/update.md for release changes.