------------------------------------------------------------------------------

Temporary workarounds: none

********>amber9.remdrestart.bugfix:
Author: Daniel R. Roe
Date: 09/22/2008

Programs: sander.MPI

Description: Fixes problem where restarting REMD run resulted in wrong input
             coordinate file being read on exchange 1.

Affected files: multisander.f 

Fix: Run this patch in the $AMBERHOME directory, with:
     $ patch -p0 -N -r patch_rejects < amber9.remdrestart.bugfix

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--- src/sander/multisander.f	2006-04-03 19:35:55.000000000 -0400
+++ src/sander/multisander.f	2008-09-22 13:42:39.000000000 -0400
@@ -99,6 +99,10 @@
 
    character (len=80) origrestrt
 
+!  REMD: Save original input coordinate file name in case of restarting a REMD
+!        run, since the call to mdfil will change it.
+   character (len=80) originpcrd
+
    integer ierror,  masterid, i
    character ext*3
 
@@ -277,6 +281,10 @@
 
                      origrestrt = restrt
 
+                     ! save the original input coordinates in case we are restarting a REMD run - 
+                     ! this has the coordinates at the correct temperature for exchange 1
+                     originpcrd = inpcrd
+
                   end if
                   i = i + 1
                end if
@@ -664,6 +672,11 @@
 
             restrt = origrestrt
 
+            ! If this run is being restarted, the current input 
+            ! coordinates will need to be read after call to 
+            ! mdfil().
+            inpcrd = originpcrd
+
             if (debugremd)  write (41+worldrank,*) "called mdfil to change file names"
 
             ! mdfil sets facc to W for REM, set it back to append
@@ -679,7 +692,13 @@
             if (currx > 1) then
                  inpcrd = restrt
                  if (debugremd) write (41+worldrank,*) "copying restrt to inpcrd"
-            endif
+            elseif ( currx==1 .and. irest==1 ) then
+            ! If this is the first exchange and we are restarting the run,
+            ! restore input coordinate file name since this has the correct
+            ! temperature.
+               if (debugremd) write (41+worldrank,*) "REMD restart - restoring original inpcrd"
+               inpcrd = originpcrd
+            endif 
 
 
             if (debugremd) then