From a296c43d7887b131417650707072f8681d05e331 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Gu=C3=A9nol=C3=A9?= <julien.guenole@fau.de>
Date: Fri, 1 Sep 2017 20:49:32 +0200
Subject: [PATCH] flag to control the initial delay for dtshrink

---
 src/min.cpp           | 7 +++++++
 src/min.h             | 1 +
 src/min_adaptglok.cpp | 5 ++++-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/min.cpp b/src/min.cpp
index 8e775e5609..bf2149cd19 100644
--- a/src/min.cpp
+++ b/src/min.cpp
@@ -64,6 +64,7 @@ Min::Min(LAMMPS *lmp) : Pointers(lmp)
   tmin = 0.02;
   integrator = 0;
   halfstepback_flag = 1;
+  delaystep_start_flag = 1;
   relaxbox_mod = 1000000;
   relaxbox_rate = 0.33;
   relaxbox_flag = 0;
@@ -692,6 +693,12 @@ void Min::modify_params(int narg, char **arg)
       else if (strcmp(arg[iarg+1],"no") == 0) halfstepback_flag = 0;
       else error->all(FLERR,"Illegal min_modify command");
       iarg += 2;       
+    } else if (strcmp(arg[iarg],"initialdelay") == 0) {
+      if (iarg+2 > narg) error->all(FLERR,"Illegal min_modify command");
+      if (strcmp(arg[iarg+1],"yes") == 0) delaystep_start_flag = 1;
+      else if (strcmp(arg[iarg+1],"no") == 0) delaystep_start_flag = 0;
+      else error->all(FLERR,"Illegal min_modify command");
+      iarg += 2;       
     } else if (strcmp(arg[iarg],"integrator") == 0) {
       if (iarg+2 > narg) error->all(FLERR,"Illegal min_modify command");
       if (strcmp(arg[iarg+1],"eulerimplicit") == 0) integrator = 0;
diff --git a/src/min.h b/src/min.h
index 62024fddaf..6cb7fcfcd6 100644
--- a/src/min.h
+++ b/src/min.h
@@ -65,6 +65,7 @@ class Min : protected Pointers {
   double tmax,tmin;           // timestep multiplicators max, min
   int integrator;             // Newton integration: euler, leapfrog, verlet...
   int halfstepback_flag;      // half step backward when v.f <= 0.0
+  int delaystep_start_flag;   // delay the initial dt_shrink
   double relaxbox_mod;        // Bulk modulus used for box relax
   double relaxbox_rate;       // for box relaxation to 0 pressure
   int relaxbox_flag;          // 1: box relaxation iso; 2: aniso
diff --git a/src/min_adaptglok.cpp b/src/min_adaptglok.cpp
index 3c54201e09..8deaa82691 100644
--- a/src/min_adaptglok.cpp
+++ b/src/min_adaptglok.cpp
@@ -315,7 +315,10 @@ int MinAdaptGlok::iterate(int maxiter)
 
     } else {
       last_negative = ntimestep;
-      if (ntimestep - ntimestep_start > delaystep) {
+      int delayflag = 1;
+      if (ntimestep - ntimestep_start < delaystep && delaystep_start_flag)
+        delayflag = 0;
+      if (delayflag) {
         alpha = alpha0;
         if (dt*dtshrink >= dtmin) {
           dt *= dtshrink;