Gaussian-like Renderer¶

Item	Value
Format ID	`fakeg`
Extensions	`.fakeg`
Read	No
Write	Yes
Registry role	File writer
Data level	Parsed Gaussian output data

fakeg renders parsed Gaussian output data as Gaussian-like text for human inspection, compatibility testing, and downstream-tool handoff. It is not a byte-for-byte Gaussian log reproducer.

format_transform("fakeg") follows the general transform default frame=-1; pass frame="all" when full-file Gaussian-like rendering is required.

Python

from molop import AutoParser

gaussian_log = AutoParser(
    "calculation.log",
    parser_detection="g16log",
    n_jobs=1,
)[0]
rendered = gaussian_log.format_transform("fakeg", frame="all")
print(type(rendered).__name__)

Output type

Text Only

str

G16LogFile.render_fakeg() defaults to frame="all", unlike format_transform().

Capability	Support	Rendered content	Boundaries
File-level Gaussian-like writer	Partial	`.fakeg` files from parsed Gaussian output data.	File-level rendering only; frame-level fakeG writing is not provided, the selected frames follow `frame`, and byte-for-byte Gaussian log reproduction is not claimed.
Structure and SCF energy rendering	Partial	Normalized orientation and SCF-cycle text from coordinate and energy fields.	Rendered sections are semantic Gaussian-like text, not original log text.
Vibrational frequency rendering	Partial	Frequency, reduced-mass, force-constant, IR-intensity, and per-mode displacement sections.	Current coverage is limited to frequency and IR-related fields; Raman/VCD sections are not advertised.
Thermochemistry rendering	Partial	Temperature, correction, energy, entropy, heat-capacity, mass, inertia, and rotational/vibrational metadata.	This is a normalized thermochemistry summary, not a complete Gaussian thermochemistry pretty-printer.
Reparseable frequency and thermochemistry output	Supported	Rendered frequency and thermochemistry content can be parsed back into frame fields.	The round trip proves supported semantic fields, not byte-for-byte equivalence with Gaussian output.

fakeG Capability Matrix¶

The matrix distinguishes structured field-driven reconstruction from component raw_text fallback. Only field-driven reconstruction can synthesize a section without the original Gaussian log.

fakeG capability	Data source	Structured reconstruction	Reparse	Source fidelity	Current boundary
Registry file writer	Coordinate-bearing file model	Supported	Partial	Unsupported	Registered as a `.fakeg` file writer; rich output depends on Gaussian result fields being present on input frames.
Registry frame writer	Single frame	Unsupported	Not applicable	Not applicable	`frame.format_transform("fakeg")` fails because no fakeG frame writer is registered.
`frame.render_fakeg()`	G16Log frame	Supported	Partial	Unsupported	The model method can render one frame directly; this is distinct from registry frame writing.
Frame selection	`frame` selector	Supported	Not applicable	Not applicable	`format_transform()` defaults to `-1`; `G16LogFile.render_fakeg()` defaults to `"all"` and accepts int/slice/list/all.
Separate output	`embed_in_one_file=False`	Supported	Partial	Unsupported	`render_fakeg()` can return one string per frame; registry disk output still follows the common file-writer contract.
File header	Version, options, keywords, title	Supported	Partial	Unsupported	Rebuilds a Gaussian-like banner, Link0, route, and title; a missing route becomes `#p fakeg`.
Shared-memory CPU line	`%nprocshared`	Supported	Partial	Unsupported	Reuses the Gaussian Link0 parser; nonnumeric values produce a generic description.
`Symbolic Z-matrix` header	First-frame atoms/coords/charge/multiplicity	Supported	Supported	Unsupported	The label follows Gaussian convention, but current output contains Cartesian atom coordinates rather than the original Z-matrix.
Input/standard orientation	Atoms, coords, standard_coords	Supported	Supported	Unsupported	Standard orientation takes priority; center/type fields and precision use a fixed template.
SCF energy	`energies.reference_energy`	Supported	Supported	Unsupported	Emits `SCF Done: E(SCF)` with one synthetic cycle; functional labels, cycle counts, and convergence history are not retained.
Post-HF energy	MP2-MP5, CCSD, CCSD(T) fields	Unsupported	Unsupported	Unsupported	Corresponding Gaussian post-HF energy lines are not generated.
Total spin	`total_spin`	Supported	Partial	Unsupported	`S**2` and `S` can render; spin-contamination diagnostics are not reconstructed.
MO and populations	`molecular_orbitals`, `charge_spin_populations`	Raw/unsupported	Not guaranteed	Unsupported	No field-driven canonical renderer exists; parsed component raw text may be returned when available.
Dipole / polarizability / multipoles	`polarizability`	Raw/unsupported	Not guaranteed	Unsupported	The component tree may carry raw text, but pure model fields cannot synthesize the complete response section.
Harmonic frequencies	`vibrations.frequencies`	Supported	Supported	Unsupported	Up to three modes render per batch with synthetic `A` symmetry labels.
Reduced mass / force constant / IR	Corresponding `vibrations` arrays	Supported	Supported	Unsupported	Lines render only when fields exist, using fixed format and precision.
Normal-mode displacement	`vibration_modes`, atoms	Supported	Supported	Unsupported	Full frequency blocks render per-atom vectors; a single child-node renderer provides only a limited preview.
Raman / VCD / ROA	No stable fields	Unsupported	Unsupported	Unsupported	The frequency header uses Gaussian Raman wording, but no Raman activity or depolarization values are emitted.
Thermochemistry header	Temperature, pressure	Supported	Supported	Unsupported	Only available values render; missing conditions are not inferred.
Mass, inertia, rotational/vibrational temperatures	`thermal_informations`	Supported	Supported	Unsupported	Uses fixed Gaussian-like labels and precision rather than source table layout.
ZPVE / thermal corrections	ZPVE, TCE, TCH, TCG	Supported	Supported	Unsupported	Units and values come from normalized containers.
U0 / UT / H / G	Thermal summary fields	Supported	Supported	Unsupported	Generates summary lines that MolOP’s Gaussian parser can recognize again.
Entropy / heat capacity	`S`, `C_V`	Supported	Supported	Unsupported	Emits normalized total values and a thermochemistry header, not component breakdowns.
Cartesian forces	`forces`	Raw/unsupported	Not guaranteed	Unsupported	No field-driven force-table renderer exists; original component raw text may survive.
Cartesian Hessian	`hessian`	Raw/unsupported	Not guaranteed	Unsupported	No field-driven complete second-derivative renderer exists.
Optimization convergence	`geometry_optimization_status`	Partial	Supported	Unsupported	File-level multiframe rendering generates step number and four convergence metrics; single-frame output mainly relies on component content.
Multiframe optimization selection	Optimization status + total energy + no vibrations	Supported	Supported	Unsupported	Only matching optimization frames enter the body; other selected frames may be omitted.
Frequency-frame selection	Last frame containing vibrations	Supported	Supported	Unsupported	Multiframe rendering selects only the last frequency frame and is not a complete frame-by-frame dump.
Runtime	`running_time`	Partial	Partial	Unsupported	Single-frame output can emit `Job cpu time`; multiframe file bodies remove per-frame runtime lines.
Termination	Renderer-generated	Supported	Supported	Unsupported	`Normal termination` is appended after multiframe optimization/frequency sections and does not prove the source calculation terminated normally.
Whole component-tree rendering	Parsed/synthetic components	Partial	Partial	Unsupported	Nodes with dedicated renderers use payload fields; other nodes may return `raw_text`.
Named component node	`component_tree.render_node(name)`	Supported	Not applicable	Unsupported	Nodes such as `l716.forceconstants`, `l716.vibration.mode[0]`, and temperature can render independently.
fakeG reparsing	Generated Gaussian-like text	Partial	Supported	Not applicable	Structure, optimization frames, frequency, and thermochemistry are verified; all source fields are not guaranteed to round-trip.
Original Gaussian-log reproduction	Source log	Unsupported	Not applicable	Unsupported	Original Link order, iterations, banners, diagnostics, timestamps, and byte layout are not retained.

fakeG is designed to produce text that is sufficiently Gaussian-like for tests and downstream compatibility and can be reparsed by MolOP for covered fields. It must not be treated as evidence of source calculation success, original termination status, or complete provenance.