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expint
Exponential integral
Y = expint(X)The exponential integral is defined as:
x
, is related to expint
as follows:
expint(-x+i*0) = -Ei(x) - i*pi Ei(x) = real(-expint(-x))
Y = expint(X)
evaluates the exponential integral for each element of X
.
For elements of X
in the domain
, expint
uses a series expansion representation (equation 5.1.11 in [1]):X
, expint
uses a continued fraction representation (equation 5.1.22 in [1]):