From 671cda3c0f13f2eb38988ff0bfd5f5e9579b5fec Mon Sep 17 00:00:00 2001
From: gwm17 <gmccann@fsu.edu>
Date: Thu, 1 Dec 2022 09:39:02 -0500
Subject: [PATCH] Fix bug in integrator where occasionally step past 0 energy
 when stopping in material

---
 catima/gwm_integrators.cpp | 9 +++++++++
 catima/gwm_integrators.h   | 7 ++++++-
 gwm_test/gwm_test.cpp      | 7 ++++++-
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/catima/gwm_integrators.cpp b/catima/gwm_integrators.cpp
index 52963b6..34f4bcd 100644
--- a/catima/gwm_integrators.cpp
+++ b/catima/gwm_integrators.cpp
@@ -1,3 +1,8 @@
+/*
+ * Simple energy  loss integrators for forward and reverse cases. 
+ *
+ * Dec 2022, Gordon McCann
+ */
 #include "catima/gwm_integrators.h"
 
 namespace catima {
@@ -34,6 +39,10 @@ namespace catima {
             {
                 return e_in*proj.A;
             }
+            else if (e_final > 0.0)
+            {
+                return e_in * proj.A; //In case an integration step takes us below 0
+            }
             else
             {
                 e_step = dedx(proj, mat, c)*x_step*A_recip;
diff --git a/catima/gwm_integrators.h b/catima/gwm_integrators.h
index 6ccf939..a4d4592 100644
--- a/catima/gwm_integrators.h
+++ b/catima/gwm_integrators.h
@@ -1,3 +1,8 @@
+/*
+ * Simple energy  loss integrators for forward and reverse cases. 
+ *
+ * Dec 2022, Gordon McCann
+ */
 #ifndef GWM_INTEGRATORS_H
 #define GWM_INTEGRATORS_H
 
@@ -10,4 +15,4 @@ namespace catima {
     double reverse_integrate_energyloss(Projectile& proj, const Material& mat, const Config& c=default_config);
 }
 
-#endif
\ No newline at end of file
+#endif
diff --git a/gwm_test/gwm_test.cpp b/gwm_test/gwm_test.cpp
index 29e78eb..d90c965 100644
--- a/gwm_test/gwm_test.cpp
+++ b/gwm_test/gwm_test.cpp
@@ -1,3 +1,8 @@
+/*
+ * Testing for gwm_integrators
+ *
+ * Dec 2022, Gordon McCann
+ */
 #include "catima/gwm_integrators.h"
 #include "catima/nucdata.h"
 #include <iostream>
@@ -14,4 +19,4 @@ int main()
     result = catima::reverse_integrate_energyloss(p1, mat1);
     std::cout<<"Reverse Energy loss (MeV): "<<result<<" Initial energy: "<<p1.T<<std::endl;
 
-}
\ No newline at end of file
+}