:py:mod:`evomap.mapping._sammon`
================================

.. py:module:: evomap.mapping._sammon

.. autoapi-nested-parse::

   Nonlinear Sammon Mapping, as proposed in:

   Sammon, J. W. (1969). A nonlinear mapping for data structure analysis. IEEE Transactions on computers, 100(5), 401-409.



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

Classes
~~~~~~~

.. autoapisummary::

   evomap.mapping._sammon.Sammon



Functions
~~~~~~~~~

.. autoapisummary::

   evomap.mapping._sammon._check_prepare_input_sammon
   evomap.mapping._sammon._sammon_stress_function
   evomap.mapping._sammon._sammon_stress_gradient



.. py:class:: Sammon(n_dims=2, n_iter=2000, n_iter_check=50, init=None, verbose=0, input_type='distance', max_halves=5, tol=0.001, n_inits=1, step_size=1)


   .. py:method:: fit(X)


   .. py:method:: fit_transform(X)



.. py:function:: _check_prepare_input_sammon(D)

   Check and, if necessary, prepare data for Sammon Mapping.

   :param D: Input distance matrix.
   :type D: ndarray of shape (n_samples, n_samples)

   :returns: Prepared input data
   :rtype: ndarray of shape (n_samples, n_samples)


.. py:function:: _sammon_stress_function(positions, disparities, compute_error=True, compute_grad=True)


.. py:function:: _sammon_stress_gradient(Y, D_map, D)