From 93373c8734b6b4c5a9a292c68994c8d2c2b041d5 Mon Sep 17 00:00:00 2001
From: "Joachim Wuttke (h)" <j.wuttke@fz-juelich.de>
Date: Fri, 8 May 2020 21:33:46 +0200
Subject: [PATCH] Core: FFSphere: comment to explain series expansion
---
Core/HardParticle/FormFactorFullSphere.cpp | 1 +
1 file changed, 1 insertion(+)
diff --git a/Core/HardParticle/FormFactorFullSphere.cpp b/Core/HardParticle/FormFactorFullSphere.cpp
index e908943c71e..c923c93f223 100644
--- a/Core/HardParticle/FormFactorFullSphere.cpp
+++ b/Core/HardParticle/FormFactorFullSphere.cpp
@@ -61,6 +61,7 @@ complex_t FormFactorFullSphere::evaluate_for_q(cvector_t q) const
#ifdef POLYHEDRAL_DIAGNOSTIC
diagnosis = {0, 1};
#endif
+ // expand sin(qR)-qR*cos(qR) up to qR^5
ret = 4 * M_PI / 3 * pow(R, 3) * (1. - 0.1 * pow(qR, 2));
} else {
#ifdef POLYHEDRAL_DIAGNOSTIC
--
GitLab