From 3115ecdabb0db9390fbe7ecfedab3abd07ab089c Mon Sep 17 00:00:00 2001
From: Grzegorz Kowal <grzegorz@amuncode.org>
Date: Wed, 19 Aug 2020 22:38:51 -0300
Subject: [PATCH] IO: Restart job from the last available restart snapshot.

If parameter 'restart_number' was not set or is negative, it is
determined from the last available restart snapshot. The restart
snapshots should be all in the same restart path in the complete
sequence, i.e., from first one to the last one.

Signed-off-by: Grzegorz Kowal <grzegorz@amuncode.org>
---
 sources/io.F90 | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/sources/io.F90 b/sources/io.F90
index 93fcf99..43fe3cf 100644
--- a/sources/io.F90
+++ b/sources/io.F90
@@ -251,6 +251,7 @@ module io
     use hdf5           , only : h5pset_deflate_f, h5pset_filter_f
 #endif /* HDF5 */
     use iso_fortran_env, only : error_unit
+    use mpitools       , only : nproc
     use parameters     , only : get_parameter
 
 ! local variables are not implicit by default
@@ -264,6 +265,8 @@ module io
 
 ! local variables
 !
+    logical               :: test
+    character(len=255)    :: dname
     character(len=255)    :: sformat = "xml"
     character(len=255)    :: precise = "off"
     character(len=255)    :: ghosts  = "on"
@@ -275,6 +278,7 @@ module io
     integer, dimension(1) :: cd_values = 3
 #endif /* HDF5 */
 
+
 #ifdef HDF5
 ! local parameters
 !
@@ -341,6 +345,38 @@ module io
       restart_format = snapshot_xml
     end select
 
+! check the last available restart snapshot
+!
+    if (nrest < 0) then
+
+      test = .true.
+      nrest = 0
+
+      select case(restart_format)
+#ifdef HDF5
+      case(snapshot_hdf5)
+        do while (test)
+          nrest = nrest + 1
+          write(dname, "(a,'r',i6.6,'_',i5.5,'.h5')")                          &
+                                                trim(respath), nrest, nproc
+          inquire(file = dname, exist = test)
+        end do
+#endif /* HDF5 */
+      case default
+        do while (test)
+          nrest = nrest + 1
+          write(dname, "(a,'restart-',i5.5)") trim(respath), nrest
+#ifdef __INTEL_COMPILER
+          inquire(directory = dname, exist = test)
+#else /* __INTEL_COMPILER */
+          inquire(file = dname, exist = test)
+#endif /* __INTEL_COMPILER */
+        end do
+      end select
+
+      nrest = nrest - 1
+    end if
+
 ! get compression format and level for XML+binary files
 !
     call get_parameter("compression_format", cformat)