Merge remote-tracking branch 'upstream/devel' into devel

Author: Han Wang

.github/workflows/test.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8]
+        python-version: [3.7, 3.8, 3.9]
 
     steps:
     - uses: actions/checkout@v2

dpdata/vasp/outcar.py

@@ -1,10 +1,12 @@
 import numpy as np
+import re
 
 def system_info (lines, type_idx_zero = False) :
     atom_names = []
     atom_numbs = None
     nelm = None
-    for ii in lines: 
+    for ii in lines:
+        ii_word_list=ii.split()
         if 'TITEL' in ii : 
             # get atom names from POTCAR info, tested only for PAW_PBE ...
             _ii=ii.split()[3]
@@ -13,10 +15,12 @@ def system_info (lines, type_idx_zero = False) :
                 atom_names.append(_ii.split('_')[0])
             else:
                 atom_names.append(_ii)
-        elif 'NELM' in ii and nelm == None:
-            # will read only first nelm
-            nelm = int(ii.split()[2].rstrip(";"))
-        elif 'ions per type' in ii :
+        #a stricker check for "NELM"; compatible with distingct formats in different versions(6 and older, newers_expect-to-work) of vasp
+        elif nelm is None:
+            m = re.search(r'NELM\s*=\s*(\d+)', ii)
+            if m:
+                nelm = int(m.group(1))
+        if 'ions per type' in ii :
             atom_numbs_ = [int(s) for s in ii.split()[4:]]
             if atom_numbs is None :                
                 atom_numbs = atom_numbs_