From 967b2e2b77764ffc453af2b5e3fb35edde6a7ffe Mon Sep 17 00:00:00 2001
From: "Joachim Wuttke (h)" <j.wuttke@fz-juelich.de>
Date: Tue, 22 Nov 2022 11:10:09 +0100
Subject: [PATCH] Optimize TruncatedSphere ff
---
Sample/HardParticle/TruncatedSphere.cpp | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/Sample/HardParticle/TruncatedSphere.cpp b/Sample/HardParticle/TruncatedSphere.cpp
index 9df0dd19681..7f39a2fd444 100644
--- a/Sample/HardParticle/TruncatedSphere.cpp
+++ b/Sample/HardParticle/TruncatedSphere.cpp
@@ -43,13 +43,13 @@ complex_t TruncatedSphere::formfactor_at_bottom(C3 q) const
* (m_height * m_height * (3. * m_radius - m_height)
- m_dh * m_dh * (3. * m_radius - m_dh));
+ const complex_t Q2 = std::sqrt(q.x() * q.x() + q.y() * q.y()); // NOT the modulus!
+ const double R2 = m_radius * m_radius;
+
complex_t integral = ComplexIntegrator().integrate(
[=](double Z) {
- double Rz = std::sqrt(m_radius * m_radius - Z * Z);
- complex_t qx = q.x();
- complex_t qy = q.y();
- complex_t q_p = std::sqrt(qx * qx + qy * qy); // NOT the modulus!
- return Rz * Rz * Math::Bessel::J1c(q_p * Rz) * exp_I(q.z() * Z);
+ const double R2Z2 = R2 - Z * Z;
+ return R2Z2 * Math::Bessel::J1c(Q2 * sqrt(R2Z2)) * exp_I(q.z() * Z);
},
m_radius - m_height, m_radius - m_dh);
return M_TWOPI * integral * exp_I(q.z() * (m_height - m_radius));
--
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