Please find attached a quick patch to correct
Law2_ScGeom_ViscElPhys_Basic documentation to match source code, per
discussion https://answers.launchpad.net/yade/+question/691021

(apologies for the delay between the launchpad question and the patch)

Daniel

From 1fa0cd10a7831bffb015c2efa10e433f854352a1 Mon Sep 17 00:00:00 2001
From: Daniel Kiracofe <kirac...@ucmail.uc.edu>
Date: Mon, 20 Jul 2020 14:42:17 -0400
Subject: [PATCH] correct Law2_ScGeom_ViscElPhys_Basic documentation to match

---
pkg/dem/ViscoelasticPM.hpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pkg/dem/ViscoelasticPM.hpp b/pkg/dem/ViscoelasticPM.hpp
index a2ef0b09a..f00dd1bae 100644
--- a/pkg/dem/ViscoelasticPM.hpp
+++ b/pkg/dem/ViscoelasticPM.hpp
@@ -137,10 +137,10 @@ public:
"the Young modulus (young) and poisson's ratio (poisson) instead of the normal and spring constant (kn and ks). "
"In this case, the equivalent parameters are evaluated the same way as the previous case with $kn_x = E_x d_x$, "
"$ks_x = v_x kn_x$, where $E_x$, $v_x$ and $d_x$ are Young modulus, poisson's ratio and diameter of particle x. "
-      "\n\n - If Yound modulus (young), poisson's ratio (poisson), normal and tangential restitution coefficient (en,et) "
+      "\n\n - If Youngs modulus (young), poisson's ratio (poisson), normal and tangential restitution coefficient (en,et)"
"are precised, the equivalent stiffnesses are evaluated as previously:  $K_n = 2\\frac{kn_1 kn_2}{kn_1 + kn_2}$, "
"$kn_x = E_x d_x$, $K_s = 2(ks_1 ks_2)/(ks_1 + ks_2)$, $ks_x = v kn_x$. The damping constant is computed at each "
-      "contact in order to fulfill the normal restitution coefficient $e_n = (en_1 en_2)/(en_1 + en_2)$. This is "
+      "contact in order to fulfill the normal restitution coefficient $e_n = (en_1 + en_2)/2$. This is "
"achieved resolving numerically equation 21 of [Schwager2007]_ (There is in fact a mistake in the article from "
"equation 18 to 19, so that there is a change in sign).  Be careful in this configuration the tangential "
"restitution coefficient is set to 1 (no tangential damping). This formulation imposes directly the normal "
--
2.20.1


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