depot.api.private.shrink
========================

.. py:module:: depot.api.private.shrink

.. autoapi-nested-parse::

   Shrink Areas and electrified terminus Stations to peak observed concurrency.

   Internal helpers for :func:`eflips.depot.api.shrink_to_peak_usage`. Operates on
   events already persisted to the database (run after
   :func:`eflips.depot.api.add_evaluation_to_database`).



Functions
---------

.. autoapisummary::

   depot.api.private.shrink._compute_peak_concurrency
   depot.api.private.shrink._round_capacity_for_area_type
   depot.api.private.shrink._shrink_areas_to_peak
   depot.api.private.shrink._shrink_stations_to_peak


Module Contents
---------------

.. py:function:: _compute_peak_concurrency(events, resolution)

   Count the maximum number of simultaneously-active events.

   Each event occupies time blocks ``[floor(start/res), max(start+1, ceil(end/res)))``
   relative to the earliest start. Back-to-back events at a block boundary do not
   overlap; sub-resolution events still count as one block.


.. py:function:: _round_capacity_for_area_type(peak, area)

   Round ``peak`` UP to the next valid capacity for ``area.area_type``.

   Preserves the CHECK constraint defined on :class:`eflips.model.Area`:

   - DIRECT_ONESIDE: any positive int
   - DIRECT_TWOSIDE: capacity must be even
   - LINE: capacity must be a multiple of ``row_count`` (which is preserved)


.. py:function:: _shrink_areas_to_peak(scenario, session, resolution)

   Shrink every :class:`Area` in ``scenario`` to its peak observed usage.

   Areas whose peak concurrency is zero are deleted along with their
   :class:`AssocAreaProcess` rows. If we somehow compute a zero peak while
   events still reference the area we raise :class:`RuntimeError` rather than
   silently delete persisted state.


.. py:function:: _shrink_stations_to_peak(scenario, session, resolution)

   Shrink electrified opportunity-charging Stations to peak observed usage.

   Only Stations with ``is_electrified=True`` and
   ``charge_type=ChargeType.OPPORTUNITY`` are considered. If peak > 0 we update
   ``amount_charging_places`` and recompute ``power_total``. If peak == 0 we
   un-electrify the station, atomically nulling all electrification fields to
   keep the CHECK constraint satisfied.