From e9d4b7a10dace9c33fe0332bd6da9230a10fa03c Mon Sep 17 00:00:00 2001
From: sjplimp <sjplimp@f3b2605a-c512-4ea7-a41b-209d697bcdaa>
Date: Thu, 3 Apr 2014 14:57:27 +0000
Subject: [PATCH] git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@11689
 f3b2605a-c512-4ea7-a41b-209d697bcdaa

---
 src/irregular.cpp | 50 ++++++++++++++++++++++++++++++++++++++++++++++-
 src/irregular.h   |  8 +++++++-
 2 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/src/irregular.cpp b/src/irregular.cpp
index 679428fb48..b9203ebdd8 100644
--- a/src/irregular.cpp
+++ b/src/irregular.cpp
@@ -24,6 +24,12 @@
 
 using namespace LAMMPS_NS;
 
+// allocate space for static class variable
+// prototype for non-class function
+
+int *Irregular::proc_recv_copy;
+int compare_standalone(const void *, const void *);
+
 #define BUFFACTOR 1.5
 #define BUFMIN 1000
 #define BUFEXTRA 1000
@@ -247,7 +253,7 @@ int Irregular::migrate_check()
    return total # of doubles I will recv (not including self)
 ------------------------------------------------------------------------- */
 
-int Irregular::create_atom(int n, int *sizes, int *proclist)
+int Irregular::create_atom(int n, int *sizes, int *proclist, int sort)
 {
   int i;
 
@@ -358,6 +364,33 @@ int Irregular::create_atom(int n, int *sizes, int *proclist)
     nrecvsize += length_recv[i];
   }
 
+  // sort proc_recv and num_recv by proc ID if requested
+  // useful for debugging to insure reproducible ordering of received atoms
+  // invoke by adding final arg = 1 to create_atom() call in migrate_atoms()
+
+  if (sort) {
+    int *order = new int[nrecv];
+    int *proc_recv_ordered = new int[nrecv];
+    int *length_recv_ordered = new int[nrecv];
+
+    for (i = 0; i < nrecv; i++) order[i] = i;
+    proc_recv_copy = proc_recv;
+    qsort(order,nrecv,sizeof(int),compare_standalone);
+
+    int j;
+    for (i = 0; i < nrecv; i++) {
+      j = order[i];
+      proc_recv_ordered[i] = proc_recv[j];
+      length_recv_ordered[i] = length_recv[j];
+    }
+
+    memcpy(proc_recv,proc_recv_ordered,nrecv*sizeof(int));
+    memcpy(length_recv,length_recv_ordered,nrecv*sizeof(int));
+    delete [] order;
+    delete [] proc_recv_ordered;
+    delete [] length_recv_ordered;
+  }
+
   // barrier to insure all MPI_ANY_SOURCE messages are received
   // else another proc could proceed to exchange_atom() and send to me
 
@@ -388,6 +421,21 @@ int Irregular::create_atom(int n, int *sizes, int *proclist)
   return nrecvsize;
 }
 
+/* ----------------------------------------------------------------------
+   comparison function invoked by qsort()
+   accesses static class member proc_recv_copy, set before call to qsort()
+------------------------------------------------------------------------- */
+
+int compare_standalone(const void *iptr, const void *jptr)
+{
+  int i = *((int *) iptr);
+  int j = *((int *) jptr);
+  int *proc_recv = Irregular::proc_recv_copy;
+  if (proc_recv[i] < proc_recv[j]) return -1;
+  if (proc_recv[i] > proc_recv[j]) return 1;
+  return 0;
+}
+
 /* ----------------------------------------------------------------------
    communicate atoms via PlanAtom
    sendbuf = list of atoms to send
diff --git a/src/irregular.h b/src/irregular.h
index 2581551c0f..1ca51a51c9 100644
--- a/src/irregular.h
+++ b/src/irregular.h
@@ -20,6 +20,11 @@ namespace LAMMPS_NS {
 
 class Irregular : protected Pointers {
  public:
+
+  // static variable across all Irregular objects, for qsort callback
+
+  static int *proc_recv_copy;
+
   Irregular(class LAMMPS *);
   ~Irregular();
   void migrate_atoms();
@@ -82,7 +87,7 @@ class Irregular : protected Pointers {
   PlanAtom *aplan;
   PlanData *dplan;
 
-  int create_atom(int, int *, int *);
+  int create_atom(int, int *, int *, int sort = 0);
   void exchange_atom(double *, int *, double *);
   void destroy_atom();
   int coord2proc(double *, int &, int &, int &);
@@ -95,6 +100,7 @@ class Irregular : protected Pointers {
 }
 
 #endif
+
 /* ERROR/WARNING messages:
 
 */