%feature("docstring") OT::Axial
"Axial design of experiments.

Available constructor:
    Axial(*center, levels*)

    Axial(*dimension, levels*)

Parameters
----------
center : sequence of float
    Center of the design of experiments. If not specified, the design of
    experiments is centered on :math:`\vect{0} \in \Rset^n`.
levels : sequence of float of dimension :math:`n_{level}`
    The discretisation of directions (the same for each one), without any
    consideration of unit.
dimension : positive int
    Dimension :math:`n` of the space where the design of experiments is created.

Notes
-----
Axial is a stratified design of experiments enabling to generate a pattern with
points only along the axes. It is not convenient to model interactions between
variables. The axial pattern is obtained by discretizing each direction
according to specified levels, symmetrically with respect to the center of the
design of experiments.

The number of points generated is :math:`1 + 2 n_{level}n`.

In order to scale each direction and translate the grid structure onto the
proper center, use the operator :math:`*=` and :math:`+=` of
:class:`~openturns.Sample`.

See also
--------
StratifiedExperiment

Examples
--------
>>> import openturns as ot
>>> levels = [4.0, 2.0, 7.0]
>>> myCenteredReductedGrid = ot.Axial(2, levels)
>>> mySample = myCenteredReductedGrid.generate()
>>> # Translate the grid
>>> mySample+=4
>>> # Scale each direction
>>> mySample*=2"
