research article
Approximation for the exponential integral (Theis well function)
2000
In this note, we provide an analytical approximation to the exponential integral valid for all values of its argument. The approximation is constructed by interpolation between the exponential integral's small and large asymptotes.The interpolation contains an unknown function, which is determined using the minimax criterion. The maximum error in the approximation is less than 0.07%, making it useful for routine hydrological applications.
Type
research article
Author(s)
Date Issued
2000
Published in
Volume
227
Issue
1-4
Start page
287
End page
291
Subjects
Editorial or Peer reviewed
REVIEWED
Written at
OTHER
EPFL units
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