$$ \newcommand{\uex}{{u_{\small\mbox{e}}}} \newcommand{\Aex}{{A_{\small\mbox{e}}}} \newcommand{\half}{\frac{1}{2}} \newcommand{\Oof}[1]{\mathcal{O}(#1)} $$
Implementations of variable coefficients; functions
Plain functions:
def
a
(t):
return
a_0
if
t
<
tp
else
k
*
a_0
def
b
(t):
return
1
