From ec49c7fa35c551ec7e9ef936ad48d3f2dd3efacd Mon Sep 17 00:00:00 2001
From: Berk Hess <hess@kth.se>
Date: Mon, 3 Jun 2013 20:56:19 +0200
Subject: [PATCH] fixed DD internal state corruption with energy minimization

With energy minimization we need to reload old DD states after
steps are rejected. There were two bookkeeping issues in the reload.
This could lead to all kinds of, but no silent, errors.
Fixes #1272

Change-Id: Ia44c3bad27f3efdee76fa93dd281690e44dde700
---
 src/mdlib/domdec.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/mdlib/domdec.c b/src/mdlib/domdec.c
index ad5097d853..2472a37ac9 100644
--- a/src/mdlib/domdec.c
+++ b/src/mdlib/domdec.c
@@ -2459,6 +2459,8 @@ static void set_zones_ncg_home(gmx_domdec_t *dd)
     {
         zones->cg_range[i] = dd->ncg_home;
     }
+    /* zone_ncg1[0] should always be equal to ncg_home */
+    dd->comm->zone_ncg1[0] = dd->ncg_home;
 }
 
 static void rebuild_cgindex(gmx_domdec_t *dd,
@@ -9181,7 +9183,7 @@ void dd_partition_system(FILE                *fplog,
     t_block           *cgs_gl;
     gmx_large_int_t    step_pcoupl;
     rvec               cell_ns_x0, cell_ns_x1;
-    int                i, j, n, cg0 = 0, ncg_home_old = -1, ncg_moved, nat_f_novirsum;
+    int                i, j, n, ncgindex_set, ncg_home_old = -1, ncg_moved, nat_f_novirsum;
     gmx_bool           bBoxChanged, bNStGlobalComm, bDoDLB, bCheckDLB, bTurnOnDLB, bLogLoad;
     gmx_bool           bRedist, bSortCG, bResortAll;
     ivec               ncells_old = {0, 0, 0}, ncells_new = {0, 0, 0}, np;
@@ -9316,6 +9318,7 @@ void dd_partition_system(FILE                *fplog,
     {
         /* Clear the old state */
         clear_dd_indices(dd, 0, 0);
+        ncgindex_set = 0;
 
         set_ddbox(dd, bMasterState, cr, ir, state_global->box,
                   TRUE, cgs_gl, state_global->x, &ddbox);
@@ -9340,8 +9343,6 @@ void dd_partition_system(FILE                *fplog,
         inc_nrnb(nrnb, eNR_CGCM, dd->nat_home);
 
         dd_set_cginfo(dd->index_gl, 0, dd->ncg_home, fr, comm->bLocalCG);
-
-        cg0 = 0;
     }
     else if (state_local->ddp_count != dd->ddp_count)
     {
@@ -9361,6 +9362,7 @@ void dd_partition_system(FILE                *fplog,
         /* Build the new indices */
         rebuild_cgindex(dd, cgs_gl->index, state_local);
         make_dd_indices(dd, cgs_gl->index, 0);
+        ncgindex_set = dd->ncg_home;
 
         if (fr->cutoff_scheme == ecutsGROUP)
         {
@@ -9384,6 +9386,7 @@ void dd_partition_system(FILE                *fplog,
 
         /* Clear the non-home indices */
         clear_dd_indices(dd, dd->ncg_home, dd->nat_home);
+        ncgindex_set = 0;
 
         /* Avoid global communication for dim's without pbc and -gcom */
         if (!bNStGlobalComm)
@@ -9429,7 +9432,7 @@ void dd_partition_system(FILE                *fplog,
 
         dd_redistribute_cg(fplog, step, dd, ddbox.tric_dir,
                            state_local, f, fr, mdatoms,
-                           !bSortCG, nrnb, &cg0, &ncg_moved);
+                           !bSortCG, nrnb, &ncgindex_set, &ncg_moved);
 
         wallcycle_sub_stop(wcycle, ewcsDD_REDIST);
     }
@@ -9526,8 +9529,8 @@ void dd_partition_system(FILE                *fplog,
         dd_sort_state(dd, ir->ePBC, fr->cg_cm, fr, state_local,
                       bResortAll ? -1 : ncg_home_old);
         /* Rebuild all the indices */
-        cg0 = 0;
         ga2la_clear(dd->ga2la);
+        ncgindex_set = 0;
 
         wallcycle_sub_stop(wcycle, ewcsDD_GRID);
     }
@@ -9538,7 +9541,7 @@ void dd_partition_system(FILE                *fplog,
     setup_dd_communication(dd, state_local->box, &ddbox, fr, state_local, f);
 
     /* Set the indices */
-    make_dd_indices(dd, cgs_gl->index, cg0);
+    make_dd_indices(dd, cgs_gl->index, ncgindex_set);
 
     /* Set the charge group boundaries for neighbor searching */
     set_cg_boundaries(&comm->zones);
-- 
2.22.0