Collapsed As-Built / But-For analysis on a post-impact XER.
Implements AACE RP 29R-03 §3.8 Modeled / Subtractive / Single
Base method (paired with MIP 3.3 Windows for the dual-method
gap report per SCL §11.5). Validates a forensic windows
analysis (MIP 3.3) by independently computing the same
project drift via subtractive removal of delays from the
as-built schedule.
For each delay event, the as-built duration of every
``affected_activity`` is shortened by ``impact_days`` (or
removed entirely if ``removal_method="remove"``), then CPM
re-runs and the resulting "but-for" finish date is compared
to the as-built finish. Cumulative pass removes ALL events at
once for a project-level but-for finish.
Use this tool when opposing counsel demands a but-for analysis
or you need a dual-method validation pairing §3.3 (windows) with
§3.8 (collapsed-as-built). For prospective fragnet insertion
(MIP 3.7), use ``time_impact_analysis_fragnet`` instead.
Args:
as_built_xer_path: server-side post-impact XER (after delays incurred).
as_built_xer_content: full text of post-impact XER (alternative for hosted/remote use).
Supply EXACTLY ONE of path/content.
delay_events: list of event dicts. Each must have
``event_id``, ``affected_activities`` (list of
task_codes), and ``impact_days`` (number). Optional:
``removal_method`` ('shorten'|'remove'),
``responsible_party``, ``name``, ``description``.
output_dir: optional output dir for HTML/CSV (tempdir if "").
project_name: optional override.
removal_method: global default 'shorten' or 'remove'.
contractor_filter: when True, exclude contractor-caused
events from the cumulative pass (owner audit mode).
Returns:
{
"as_built_finish": "YYYY-MM-DD",
"per_event_results": [{event_id, but_for_finish,
impact_days_collapsed,
duration_removal_basis,
finish_driver_after_removal, ...}, ...],
# duration_removal_basis discloses WHAT duration was removed
# and on what basis; finish_driver_after_removal discloses
# WHAT drives the but-for finish (incl. whether it is bound by
# the data-date floor) so a reader sees WHY the finish did or
# did not move across data dates.
"cumulative_but_for_finish": "YYYY-MM-DD",
"cumulative_impact_days": int,
"dual_method_gap": dict | None,
"output_files": {...},
"warnings": [...],
"method": "AACE 29R-03 §3.8 (Modeled/Subtractive/Single Simulation)"
}
