.. Auto-generated by scripts/generate_problem_catalog_docs.py. Do not edit by hand.

Planar roof truss grammar (three-point symmetric variant)
=========================================================

A simplified roof-truss grammar aligned to the three-point symmetric formulation reported by Shea and Cagan.

See :doc:`../grammar` for the grammar family index.

Quick Facts
-----------

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   * - Field
     - Value
   * - Problem ID
     - ``planar_roof_truss_three_point_symmetric``
   * - Problem Family
     - grammar
   * - Implementation
     - ``design_research_problems.problems.grammar._planar_truss:PlanarTrussSpanProblem``
   * - Capabilities
     - ``discrete-actions``, ``external-adapter``, ``optional-evaluator``, ``serializable-state``, ``statement-markdown``
   * - Study Suitability
     - none
   * - Tags
     - ``grammar``, ``truss``, ``roof``, ``discrete``, ``topology``, ``symmetric``

Taxonomy
--------

Formulation
   discrete_grammar
Convexity
   not_applicable
Design Variable Type
   discrete
Is Dynamic
   no
Orientation
   engineering_practical
Feasibility Ratio Hint
   0.25
Objective Mode
   single
Constraint Nature
   hard
Bounds Summary
   symmetric planar roof-truss topology over a fixed span
Tags
   ``grammar``, ``truss``, ``roof``, ``discrete``, ``topology``, ``symmetric``

Statement
---------

This catalog entry approximates the first planar roof-truss formulation reported in the structural essay study by Shea and Cagan: a symmetric roof truss with three roof load points. In the original study, the two outer load points could translate along the roofline. This simplified grammar fixes them at quarter-span locations while preserving the same symmetric three-point loading topology.

The state begins with pinned and roller supports plus three loaded roof joints. Designers add interior joints and members, and mirrored edits are enforced so the topology remains symmetric about mid-span.

Problem Shape
-------------

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   * - Field
     - Value
   * - State Type
     - PlanarTrussState
   * - Initial Transition Count
     - 9
   * - Initial Rule Names
     - ``add_joint``, ``add_joint_pair``, ``add_member``

Manifest Parameters
-------------------

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   * - Key
     - Value
   * - candidate_point_fractions
     - [[0.2, 0.2], [0.35, 0.32], [0.5, 0.22]]
   * - enforce_symmetry
     - yes
   * - load_magnitude
     - 1000
   * - max_height
     - 2.5
   * - roof_load_x_fractions
     - [0.25, 0.5, 0.75]
   * - span
     - 10

Initial Transition Summary
--------------------------

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   :header-rows: 1
   :widths: 70 30

   * - Rule Name
     - Transition Count
   * - add_joint
     - 1
   * - add_joint_pair
     - 2
   * - add_member
     - 6

Library Interface
-----------------

- ``initial_state()``
- ``enumerate_transitions(state)``
- ``enumerate_next_states(state)``
- ``evaluate(state)``