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! FFK computes modified Fresnel integrals F+/-(x) and K+/-(x).
Licensing:
This routine is copyrighted by Shanjie Zhang and Jianming Jin. However,
they give permission to incorporate this routine into a user program
provided that the copyright is acknowledged.
Modified:
23 July 2012
Author:
Shanjie Zhang, Jianming Jin
Reference:
Shanjie Zhang, Jianming Jin,
Computation of Special Functions,
Wiley, 1996,
ISBN: 0-471-11963-6,
LC: QA351.C45.
Parameters:
Input, integer ( kind = 4 ) KS, the sign code.
0, to calculate F+(x) and K+(x);
1, to calculate F_(x) and K_(x).
Input, real ( kind = 8 ) X, the argument.
Output, real ( kind = 8 ) FR, FI, FM, FA, the values of
Re[F+/-(x)], Im[F+/-(x)], |F+/-(x)|, Arg[F+/-(x)] (Degs.).
Output, real ( kind = 8 ) GR, GI, GM, GA, the values of
Re[K+/-(x)], Im[K+/-(x)], |K+/-(x)|, Arg[K+/-(x)] (Degs.).
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| integer(kind=4) | :: | ks | ||||
| real(kind=8) | :: | x | ||||
| real(kind=8) | :: | fr | ||||
| real(kind=8) | :: | fi | ||||
| real(kind=8) | :: | fm | ||||
| real(kind=8) | :: | fa | ||||
| real(kind=8) | :: | gr | ||||
| real(kind=8) | :: | gi | ||||
| real(kind=8) | :: | gm | ||||
| real(kind=8) | :: | ga |