to each cell, which may not lead to an optimal mesh and is tedious.
With the current release, $hp$-adaptive finite element methods have been further
-expanded in both the range of features in terms of decision strategies and their
-user interface, effectively making the more attractive to use. We introduced many
-new functions that automatize the general workflow for applying $hp$-decision
+expanded: New features like decision strategies have been added and the user interface
+has been overhauled, effectively making $hp$-methods more attractive to use. We introduced
+many new functions that automatize the general workflow for applying $hp$-decision
strategies, which run on top of the previous low-level implementation for both serial
and parallel applications.
In general, $p$-refinement is favorable over $h$-refinement in smooth regions of
the finite element approximation \cite[Thm.~3.4]{BabuskaSuri1990}. Thus, estimating
its smoothness provides a suitable decision indicator for $hp$-adaptation. For this
-purpose, we expand the finite element approximation into a series of orthogonal
-basis functions of increasing complexity, and consider the decay of their expansion
+purpose, we express the finite element approximation in an orthogonal
+basis of increasing frequency, and consider the decay of their expansion
coefficients as the estimation of smoothness. This has been implemented for both
Fourier coefficients \cite{BangerthKayserHerold2007} and Legendre coefficients
\cite{Mavriplis1994,HoustonSeniorSueli2003,HoustonSueli2005,EibnerMelenk2007}.