Fixed DD state collection issue

Collecting the cg distribution state to the master (for output
of replica exchange) could go wrong when the DD was out of sync.
This code path was probably never executed.

Change-Id: I14b41c15ddc827a46f7c6448fb7bd90414f8e210

diff --git a/src/gromacs/mdlib/domdec.c b/src/gromacs/mdlib/domdec.c
index 401b6effdbb07ac88670d72211724ca19a907e1a..2d2ffb0fd5f374367f2c0b18117d552d9406f658 100644 (file)
--- a/src/gromacs/mdlib/domdec.c
+++ b/src/gromacs/mdlib/domdec.c
@@ -1320,7 +1320,6 @@ static void dd_collect_cg(gmx_domdec_t *dd,
 {
     gmx_domdec_master_t *ma = NULL;
     int                  buf2[2], *ibuf, i, ncg_home = 0, *cg = NULL, nat_home = 0;
-    t_block             *cgs_gl;
 
     if (state_local->ddp_count == dd->comm->master_cg_ddp_count)
     {
@@ -1330,12 +1329,18 @@ static void dd_collect_cg(gmx_domdec_t *dd,
 
     if (state_local->ddp_count == dd->ddp_count)
     {
+        /* The local state and DD are in sync, use the DD indices */
         ncg_home = dd->ncg_home;
         cg       = dd->index_gl;
         nat_home = dd->nat_home;
     }
     else if (state_local->ddp_count_cg_gl == state_local->ddp_count)
     {
+        /* The DD is out of sync with the local state, but we have stored
+         * the cg indices with the local state, so we can use those.
+         */
+        t_block *cgs_gl;
+
         cgs_gl = &dd->comm->cgs_gl;
 
         ncg_home = state_local->ncg_gl;
@@ -1351,8 +1356,8 @@ static void dd_collect_cg(gmx_domdec_t *dd,
         gmx_incons("Attempted to collect a vector for a state for which the charge group distribution is unknown");
     }
 
-    buf2[0] = dd->ncg_home;
-    buf2[1] = dd->nat_home;
+    buf2[0] = ncg_home;
+    buf2[1] = nat_home;
     if (DDMASTER(dd))
     {
         ma   = dd->ma;
@@ -1394,7 +1399,7 @@ static void dd_collect_cg(gmx_domdec_t *dd,
 
     /* Collect the charge group indices on the master */
     dd_gatherv(dd,
-               dd->ncg_home*sizeof(int), dd->index_gl,
+               ncg_home*sizeof(int), cg,
                DDMASTER(dd) ? ma->ibuf : NULL,
                DDMASTER(dd) ? ma->ibuf+dd->nnodes : NULL,
                DDMASTER(dd) ? ma->cg : NULL);