Atom types in CHARMM FF are non-case-sensitive (#3273)

* Atom types in CHARMM FF are non-case-sensitive

* Atom type name in CHARMM RTF

* Make atom section in CHARMM PSF file to be uppercase

wrappers/python/openmm/app/charmmparameterset.py

@@ -232,6 +232,7 @@ class CharmmParameterSet(object):
         previous = ''
         for line in f:
             line = previous+line.strip()
+            line = line.upper()
             previous = ''
             if line.endswith('-'):
                 # This will be continued on the next line.
@@ -598,7 +599,7 @@ class CharmmParameterSet(object):
             own_handle = False
             f = tfile
         for line in f:
-            line = line.strip()
+            line = line.strip().upper()
             if line[:4] != 'MASS': continue
             words = line.split()
             try:

wrappers/python/openmm/app/charmmpsffile.py

@@ -569,6 +569,7 @@ class CharmmPsfFile(object):
         else:
             pointers = tuple([conv(w, int, 'pointer') for w in words])
         line = psf.readline().strip()
+        if title == 'NATOM': line = line.upper()
         if not line and title.startswith('NNB'):
             # This will correctly handle the NNB section (which has a spurious
             # blank line) as well as any sections that have 0 members.
@@ -580,6 +581,7 @@ class CharmmPsfFile(object):
             while line:
                 data.append(line)
                 line = psf.readline().strip()
+                if title == 'NATOM': line = line.upper()
         else:
             while line:
                 words = line.split()