From 20eb89a10e97c010795d76dbbfc9f21e5cecb5cb Mon Sep 17 00:00:00 2001
From: William Dawson <william.dawson@riken.jp>
Date: Wed, 27 Sep 2023 16:12:39 +0900
Subject: [PATCH] Better for solution near zero gx trace

---
 Source/Fortran/DensityMatrixSolversModule.F90 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Source/Fortran/DensityMatrixSolversModule.F90 b/Source/Fortran/DensityMatrixSolversModule.F90
index 27c9e7bf..99fe22d6 100644
--- a/Source/Fortran/DensityMatrixSolversModule.F90
+++ b/Source/Fortran/DensityMatrixSolversModule.F90
@@ -602,7 +602,7 @@ SUBROUTINE TRS4(H, ISQ, trace, K, &
 
        !! Compute Sigma - avoiding overflow
        IF (ABS(trace_gx) .LT. 1.0e-14_NTREAL) THEN
-          sigma_array(II) = sigma_max + 1.0_NTREAL
+          sigma_array(II) = 0.5_NTREAL * (sigma_max - sigma_min)
        ELSE
           sigma_array(II) = (trace - trace_fx) / trace_gx
        END IF