===============================================================
 Specify and Implement Restrictions on the Location Parameters 
===============================================================

.. r-package:: manifestos
.. r-pkgversion:: 0.8
.. r-name:: latpos_restrictions

     restrictor
     set.parms.free

Description
===========

``restrictor`` creates a linear transformation that maps a small set of linearly
unrestriced parameters to a larger set of linearly restricted parameters.

``set.parms.free`` specifies a call to ``restrictor`` in which only the specified
parameters are allowed to differ from zero.

Usage
=====

.. code-block:: r

     restrictor(C,d=numeric(m),sign=7)

     set.parms.free(...)

Arguments
=========

``C``
   The matrix involved in the linear restriction :math:`C\alpha=d`.

``d``
   The vector involved in the linear restriction :math:`C\alpha=d`.

``sign``
   The number of significant digits to use for rounding to compensate finite machine
   precision in computing the QR decomposition.

``...``
   several character vector arguments. Each character vector corresponds to one of the axes
   of the latent space, and each character string in a vector corresponds to the name of a
   policy objective that can obtain coordinate values different from zero.

Value
=====

The values of these functions are for internal use only.

If :math:`C\alpha=d` then :math:`\alpha=Q\phi+r`.  The function ``restrictor`` returns a
list with the elements "reduction" (which equals :math:`Q`) and "offset" (which equals
:math:`r`)

The function ``set.parms.free`` returns a function that generates arguments :math:`C` and
:math:`d` with which the ``restrictor`` is called inside of the function ``latpos``.