datafile: do not assume first dataset stored is also earliest in time

1 files changed, 4 insertions, 7 deletions

diff --git a/datafile.py b/datafile.py
index 5a09c4d..b7e437b 100644
--- a/datafile.py
+++ b/datafile.py
@@ -90,14 +90,15 @@ class _DataSet(object):
         self.name = name
 
         # detect the number of components
+        first_iter = self._df.itertimes[0][0][0]
         try:
-            self._slice_single_component(self._df._first_iter, 0)
+            self._slice_single_component(first_iter, 0)
             self.nb_components = 1
         except KeyError:
             c = 0
             while True:
                 try:
-                    self._slice_single_component(self._df._first_iter, 0, c)
+                    self._slice_single_component(first_iter, 0, c)
                     c += 1
                 except KeyError:
                     break
@@ -107,7 +108,7 @@ class _DataSet(object):
         self.rl   = []
         while True:
             try:
-                self._slice_single_component(self._df._first_iter, len(self.rl))
+                self._slice_single_component(first_iter, len(self.rl))
                 self.rl.append(_DataRefinementLevel(len(self.rl), self))
             except KeyError:
                 break
@@ -194,8 +195,6 @@ class DataFile(object):
     # time duration of one iteration
     _dt_iter = None
 
-    _first_iter = None
-
     # number of iterations per coarsest-level time step
     _stepsize_iter = None
 
@@ -206,8 +205,6 @@ class DataFile(object):
         self.path = path
         try:
             for it in self._f.values():
-                if self._first_iter is None and 'timestep' in it.attrs:
-                    self._first_iter = it.attrs['timestep']
                 if 'time' in it.attrs and it.attrs['time'] > 0.0:
                     self._dt_iter = it.attrs['time'] / it.attrs['timestep']
                     break