EXPEI Exponential Weighted Integral Function

Section: Mathematical Functions

Usage

Computes the exponential weighted integral function for real arguments. The expei function takes only a single argument
  y = expei(x)

where x is either a float or double array. The output vector y is the same size (and type) as x.

Function Internals

The expei function is defined by the integral:

Example

Here is a plot of the expei function over the range [-5,5].
--> x = linspace(-5,5);
--> y = expei(x);
--> plot(x,y); xlabel('x'); ylabel('expei(x)');


which results in the following plot.