bluemira.utilities.fit_tools
============================

.. py:module:: bluemira.utilities.fit_tools

.. autoapi-nested-parse::

   Fitting tools



Functions
---------

.. autoapisummary::

   bluemira.utilities.fit_tools.surface_fit
   bluemira.utilities.fit_tools.powers_arange


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

.. py:function:: surface_fit(x: numpy.ndarray, y: numpy.ndarray, z: numpy.ndarray, order: int = 2, n_grid: int = 30) -> tuple[numpy.ndarray, numpy.ndarray, numpy.ndarray, list[float], float]

   Fit a polynomial surface to a 3-D data set.

   :param x: The x values of the data set
   :param y: The y values of the data set
   :param z: The z values of the data set
   :param order: The order of the fitting polynomial
   :param n_grid: The number of gridding points to use on the x and y data

   :returns: * *x2d* -- The gridded x data (i, j indexed)
             * *y2d* -- The gridded y data (i, j indexed)
             * *zz* -- The gridded z fit data (i, j indexed)
             * *coeffs* -- The list of polynomial coefficents
             * *r2* -- The R^2 score of the fit

   :raises ValueError: x, y and z are not of equal length

   .. rubric:: Notes

   The coefficients are ordered by power, and by x and y. For an order = 2
   polynomial, the resultant equation would be:

       :math:`c_{1}x^{2}+c_{2}y^{2}+c_{3}xy+c_{4}x+c_{5}y+c_{6}`


.. py:function:: powers_arange(powers: numpy.ndarray) -> list[int]

   Reorder powers index to order by power from 1st to nth index.

   :param powers: array of powers

   :rtype: index to rearrange array