From e0788ce339d525d7749562eda39e57076298c6ab Mon Sep 17 00:00:00 2001
From: kamischi <karl-michael.schindler@web.de>
Date: Wed, 14 Feb 2024 13:18:20 +0100
Subject: [PATCH] Update phint.f90
---
source/f90/phint.f90 | 34 +++++++++++++++++++---------------
1 file changed, 19 insertions(+), 15 deletions(-)
diff --git a/source/f90/phint.f90 b/source/f90/phint.f90
index 884eb3c..57f15b5 100644
--- a/source/f90/phint.f90
+++ b/source/f90/phint.f90
@@ -1,17 +1,21 @@
double precision function phint(phi, a, u)
-! ******************************************************************
-! * *
-! * evaluate the integral from zero to phi of *
-! * *
-! * u 2 *
-! * ( ----------------------------- ) dphi *
-! * 2 2 *
-! * (1 - a * u * cos(phi)) + u *
-! * *
-! * for 0 <= phi <= pi , u >= 0 and a >= 0 *
-! * *
-! ******************************************************************
+! *******************************************************************
+! * *
+! * evaluate the integral from zero to phi of *
+! * *
+! * u 2 *
+! * ( ----------------------------- ) dphi *
+! * 2 2 *
+! * (1 - a * u * cos(phi)) + u *
+! * *
+! * for 0 <= phi <= pi , u >= 0 and a >= 0 *
+! * *
+! * Reference: *
+! * Ph. Lambin, J. P. Vigneron, and A. A. Lucas, *
+! * Phys. Rev. B 32 (1985) 8203-8215. *
+! * *
+! *******************************************************************
implicit none
@@ -54,9 +58,9 @@ double precision function phint(phi, a, u)
bi = datan2(zetai, zetar + x) - datan2(zetai, zetar - x)
rr = -(br * spr - bi * cpr) / root
ri = -(bi * spr + br * cpr) / root
- d = e * s / ((1.0d0 - e * c)**2 + u2)
- ar = d * (1.0d0 - e * c) - rr + u * ri
- ai = -d * u - ri - u * rr
+ d = e * s / ((1.0d0 - e * c)**2 + u2)
+ ar = d * (1.0d0 - e * c) - rr + u * ri
+ ai = -d * u - ri - u * rr
else
rr = -pi / root * cpr
ri = pi / root * spr
--
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