Structural analysis solvers - structsolve
=========================================

The ``structsolve`` module provides structural analysis solvers tailored for
semi-analytical models, such as the Ritz models of plates and shells of
`panels <https://github.com/saullocastro/panels>`_. With ``structsolve`` you
can run:

* Linear static analyses, `[K]\{u\} = \{f\}`, with :func:`.static`,
  :func:`.solve` or :class:`.Analysis`

* Linear buckling analyses, `([K] + \lambda [K_G])\{u\} = \{0\}`, with
  :func:`.lb`

* Frequency analyses, `([K] + \lambda^2 [M])\{u\} = \{0\}`, with :func:`.freq`

* Sparse eigenvalue solvers first, with verified results and dense solvers
  only as a last resort, also in the browser (Pyodide) and with the faulty
  Intel MKL versions that break ARPACK, see :doc:`eigensolvers`

* Non-linear static analyses with :class:`.Analysis`, using:
    - the Newton-Raphson method, full or modified, with an optional
      line-search
    - the arc-length methods of Riks and Crisfield, able to trace limit points,
      snap-through and snap-back

* Configuration-dependent loads, e.g. follower pressures, in the linear and
  non-linear static analyses, see :mod:`.callbacks`, and unsymmetric matrices
  in all the solvers, including the kinetic criterion (flutter) with
  :func:`.freq`

* Load vectors that depend on the load factor, e.g. prescribed
  displacements imposed exactly as linear constraints, in the non-linear
  static analyses, see :mod:`.callbacks`

The constrained degrees of freedom of the models, i.e. the null rows and
columns of the matrices, are removed before solving.


Code repository
---------------

https://github.com/saullocastro/structsolve


Citing this library
-------------------

Saullo G. P. Castro (2026). Structural analysis solvers tailored for semi-analytical models (Version 0.8.0). Zenodo. DOI: https://doi.org/10.5281/zenodo.2581212.


Eigenvalue solvers
------------------

.. toctree::
    :maxdepth: 1

    eigensolvers.rst


Usage examples
--------------

.. toctree::
    :maxdepth: 1

    ex_linear_static.rst
    ex_linear_buckling.rst
    ex_frequency.rst
    ex_newton_raphson.rst
    ex_arc_length.rst
    ex_follower_loads.rst
    ex_prescribed_displacements.rst


structsolve API
---------------

.. toctree::
    :maxdepth: 2

    api.rst


Installing structsolve
----------------------

Install from the distributed packages by simply doing::

    python -m pip install structsolve

or from the source code using::

    python -m pip install .

In the browser, with `Pyodide <https://pyodide.org>`_, which already
distributes NumPy and SciPy, the wheel published on PyPI is installed with
``micropip``::

    import micropip
    await micropip.install("structsolve")


Changelog
---------

https://github.com/saullocastro/structsolve/blob/main/CHANGELOG.md


License
-------

.. literalinclude:: ../../LICENSE
    :encoding: latin-1


Indices and tables
------------------

* :ref:`genindex`
* :ref:`modindex`
* :ref:`search`