What is `Ei` in SymPy.jl?

[pgbarletta]

I tried to get this integral:

@syms r::real a::real
fff = integrate((1/r)*exp(-2*a*r), (r))

and got this:

what’s that Ei?

[stillyslalom]

The classical exponential integral. Special - SymPy 1.12.1rc1 documentation

[pgbarletta]

Thanks! I’d never seen that before.