qspec.analyze.ellipse2d  (  x ,  y ,  scale_x ,  scale_y ,  phi ,  corr  )[source]

A point on an ellipse in 2d-space $$\vec{p}(x, y) = \begin{pmatrix} x + \sigma_x\cos(\phi) \\ y + \sigma_y\left[\rho_{xy}\cos(\phi) + \sqrt{1 - \rho_{xy}^2}\sin(\phi)\right] \end{pmatrix}.$$

Parameters:

xarray_like

The $x$-component of the position of the ellipse.

yarray_like

The $y$-component of the position of the ellipse.

scale_xarray_like

The amplitude $\sigma_x$ of the $x$-component.

scale_yarray_like

The amplitude $\sigma_y$ of the $y$-component.

phiarray_like

The angle $\phi$ between the vector to the point on the ellipse and the $x$-axis.

corrarray_like

The correlation coefficient $\rho_{xy}$ between the x and y data.

Returns:

(p_x, p_y)(ndarray, ndarray)

A point $\vec{p}(x, y)$ on an ellipse.