Optimizing the expint function

[Nicanor García]

Hello,

I was testing some Speech Enhancement algorithms, one of which used the expint (exponential integral) function and I noticed this function takes ages to compute.

I then tried the same algorithm in MATLAB in the same machine and noticed that the same function takes around 1/10000th of the time it was taking in Octave to compute.

Is there any way to optimize this function so it does work better in Octave?

Thank you very much.

Nicanor García O.