ass="simple">
<dt>Degree can be scalar (it is duplicated) or 2-dim vector. must be scalar if leveling by line. Note the important difference between e.g. <cite>degree = 2</cite> and</dt><dd><p><cite>degree = (2,2)</cite>. The first one uses degree as total degree, it expands then to xl,yl = [0,1,0,1,2,0],[0,0,1,1,0,2]. The second</p>
</dd>
</dl>
<p>leveling by line (controlled by axis keyword) also handle nans.
x and y are not used, but maintained for interface consistency.
fit=True returns fit component in