hermess.tests.test_algebraic_parity
===================================

.. py:module:: hermess.tests.test_algebraic_parity

.. autoapi-nested-parse::

   Parity test for the device-private algebraic-equation mechanism.

   Runs the stock SynchronousSubtransientSP machine (stator currents inlined as
   explicit expressions) and SynchronousSubtransientSP_DAE (the same currents
   declared as device-private algebraic variables/equations and handed to the DAE
   solver) on the same system, and asserts the differential-state trajectories
   agree to integrator tolerance.

   This validates the full private-algebraic path: declaration, index allocation,
   finit with private unknowns, DAE assembly/solve, and the grid/output slicing.



Attributes
----------

.. autoapisummary::

   hermess.tests.test_algebraic_parity.FIXTURE_ROOT
   hermess.tests.test_algebraic_parity._COMMON


Functions
---------

.. autoapisummary::

   hermess.tests.test_algebraic_parity.test_sp_dae_matches_eliminated_sp
   hermess.tests.test_algebraic_parity.test_sp_dae_private_constraints_hold
   hermess.tests.test_algebraic_parity.test_sp6_dae_matches_eliminated_sp6
   hermess.tests.test_algebraic_parity.test_sp_dae_line_dyn_mixed_dae
   hermess.tests.test_algebraic_parity._sorted_eig
   hermess.tests.test_algebraic_parity.test_eigenvalue_analysis_line_dyn_mixed


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

.. py:data:: FIXTURE_ROOT

.. py:data:: _COMMON

.. py:function:: test_sp_dae_matches_eliminated_sp()

   SP_DAE (explicit algebraic stator currents) must reproduce the stock SP
   (eliminated currents) on identical systems, to integrator tolerance.


.. py:function:: test_sp_dae_private_constraints_hold()

   The private stator-current constraints g = -i + <expr> must be satisfied
   along the SP_DAE trajectory: the recovered i_d/i_q (in y_full) equal the
   explicit expression evaluated on the states.


.. py:function:: test_sp6_dae_matches_eliminated_sp6()

   Subtransient Sauer-Pai 6th-order machine with the 4-equation stator block
   (i_d, i_q, psi_d, psi_q) declared as device-private algebraics. Must reproduce
   the eliminated SynchronousSubtransientSP6 to integrator tolerance.


.. py:function:: test_sp_dae_line_dyn_mixed_dae()

   Under line_dyn=True the network (voltages + line currents) is differential
   and the device-private algebraics are the only algebraic block — a mixed DAE.
   SP_DAE must run in this mode and reproduce the eliminated SP (which is a pure
   ODE there). The match is near machine precision because both integrate the
   same differential network states; only the linear private solve differs.


.. py:function:: _sorted_eig(sim)

.. py:function:: test_eigenvalue_analysis_line_dyn_mixed()

   Small-signal eigenvalue analysis for the mixed DAE (line_dyn=True with
   device-private algebraics). The privates are Schur-complemented out, leaving
   an nd = nx + nv + nl differential system. Because the eliminated ground model
   reduces to the same nd-dimensional system, the two spectra must coincide.
   Covers both SP_DAE (2 privates) and SP6_DAE (4 privates).