Function statrs::function::exponential::integral [−][src]
pub fn integral(x: f64, n: u64) -> Result<f64>
Computes the generalized Exponential Integral function
where x is the argument and n is the integer power of the
denominator term.
Errors
Returns an error if x < 0.0 or the computation could not
converge after 100 iterations
Remarks
This implementation follows the derivation in
"Handbook of Mathematical Functions, Applied Mathematics Series, Volume
55" - Abramowitz, M., and Stegun, I.A 1964
AND
"Advanced mathematical methods for scientists and engineers" - Bender,
Carl M.; Steven A. Orszag (1978). page 253
The continued fraction approac is used for `x > 1.0` while the taylor series expansions is used for `0.0 < x <= 1`