From ba27ecf6102b17d1f92037e488effbcad279cd77 Mon Sep 17 00:00:00 2001
From: rohskopf <drew.rohskopf@gmail.com>
Date: Mon, 3 Oct 2022 11:53:41 -0600
Subject: [PATCH] Add optional full flag to pair_zero

---
 src/pair_zero.cpp | 30 ++++++++++++++++++++++++++++--
 src/pair_zero.h   |  2 ++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/pair_zero.cpp b/src/pair_zero.cpp
index 83505edd35..e253cd2aa5 100644
--- a/src/pair_zero.cpp
+++ b/src/pair_zero.cpp
@@ -21,6 +21,8 @@
 #include "comm.h"
 #include "error.h"
 #include "memory.h"
+#include "neigh_list.h"
+#include "neighbor.h"
 
 #include <cstring>
 
@@ -34,6 +36,7 @@ PairZero::PairZero(LAMMPS *lmp) : Pair(lmp)
   writedata = 1;
   single_enable = 1;
   respa_enable = 1;
+  fullneighflag = 0;
 }
 
 /* ---------------------------------------------------------------------- */
@@ -85,12 +88,23 @@ void PairZero::allocate()
 
 void PairZero::settings(int narg, char **arg)
 {
-  if ((narg != 1) && (narg != 2)) error->all(FLERR, "Illegal pair_style command");
+  if ((narg != 1) && (narg != 2) && (narg != 3)) error->all(FLERR, "Illegal pair_style command");
 
   cut_global = utils::numeric(FLERR, arg[0], false, lmp);
-  if (narg == 2) {
+ 
+  if (narg == 2){
     if (strcmp("nocoeff", arg[1]) == 0)
       coeffflag = 0;
+    else if(strcmp("full", arg[1]) == 0)
+      fullneighflag = 1;
+    else
+      error->all(FLERR, "Illegal pair_style command");
+  }
+  else if (narg == 3) {
+    if (strcmp("nocoeff", arg[1]) == 0 || strcmp("nocoeff", arg[2]) == 0)
+      coeffflag = 0;
+    else if(strcmp("full", arg[1]) == 0 || strcmp("full", arg[2]) == 0)
+      fullneighflag = 1;
     else
       error->all(FLERR, "Illegal pair_style command");
   }
@@ -134,6 +148,18 @@ void PairZero::coeff(int narg, char **arg)
   if (count == 0) error->all(FLERR, "Incorrect args for pair coefficients");
 }
 
+/* ----------------------------------------------------------------------
+   init specific to this pair style
+------------------------------------------------------------------------- */
+
+void PairZero::init_style()
+{
+  if (fullneighflag == 0)
+    neighbor->add_request(this, NeighConst::REQ_DEFAULT);
+  else
+    neighbor->add_request(this, NeighConst::REQ_FULL);
+}
+
 /* ----------------------------------------------------------------------
    init for one type pair i,j and corresponding j,i
 ------------------------------------------------------------------------- */
diff --git a/src/pair_zero.h b/src/pair_zero.h
index 03b6d096a1..10102f1cad 100644
--- a/src/pair_zero.h
+++ b/src/pair_zero.h
@@ -42,6 +42,7 @@ class PairZero : public Pair {
   void compute_outer(int, int) override;
   void settings(int, char **) override;
   void coeff(int, char **) override;
+  void init_style() override;
   double init_one(int, int) override;
   void write_restart(FILE *) override;
   void read_restart(FILE *) override;
@@ -55,6 +56,7 @@ class PairZero : public Pair {
   double cut_global;
   double **cut;
   int coeffflag;
+  int fullneighflag; // 0 for half list, 1 for full list
 
   virtual void allocate();
 };