src.Math.Special.E1

src.Math.Special.E1(*args, **kwargs)

Approximated formula for Exponential integral \(E_1(x)\).

E1(x) function itself is not a vectorized function, only available to scalar operation. so we applied

@nb.vectorize([nb.float64(nb.float64), nb.float64(nb.int_)], nopython=True).

Parameters

x (np.double or array-like) – independent variable x

Returns

E1 – 1st order Exponential integral of x

Return type

np.double or array-like

Notes

Refer to 1.

References

1

D.ABarry, J.-Y.Parlange, “Approximation for the exponential integral (Theis well function)”, Journal of Hydrology, Volume 227, Issues 1–4, 31 January 2000, Pages 287-291