def readxyz(ifile):
"""readxyz(ifile) => Molecule
if got errors, raise FormatError
"""
mol = Molecule()
connects = []
line = ifile.readline()
match = re.compile(r'^ *(\d+) *(.*)$').match(line)
atmnum = int(match.group(1))
comment = match.group(2).strip()
if comment:
mol.comment = comment
for i in range(atmnum):
words = ifile.readline().split()
atom = Atom(words[1], int(words[5]))
coord = [float(x) for x in words[2:5]]
mol.addatom(atom, coord)
connects.append(words[6:])
for i, connect in enumerate(connects):
for j in connect:
mol.buildconnect(i, int(j)-1)
assert atmnum == len(mol)
return mol
