is used.
+[endsect] [/section:expint_n Exponential Integral En]
-[endsect]
[section:expint_i Exponential Integral Ei]
[graph exponential_integral_ei____float128]
-
-
[h4 Testing]
The tests for these functions come in two parts:
in polynomial as Chebyshev form, /provided/ they are computed
over the interval \[-1,1\].
-Over the a series of intervals [a,b] and [b,INF] the rational approximation
+Over the a series of intervals ['[a, b]] and ['[b, INF]] the rational approximation
takes the form:
[equation expint_i_4]
-where /c/ is a constant, and R(t) is a minimax solution optimised for low
+where /c/ is a constant, and ['R(t)] is a minimax solution optimised for low
absolute error compared to /c/. Variable /t/ is `1/z` when the range in infinite
and `2z/(b-a) - (2a/(b-a) + 1)` otherwise: this has the effect of scaling z to the
interval \[-1,1\]. As before rational approximations over arbitrary intervals
rate that Cody and Thacher achieved using J-Fractions, but marginally more
efficient given that fewer divisions are involved.
-[endsect]
-[endsect]
+[endsect] [/section:expint_n Exponential Integral En]
+
+[endsect] [/section:expint Exponential Integrals]
[/
Copyright 2006 John Maddock and Paul A. Bristow.