def test_dihedral(self):
""" Tests calculating a torsion angle between 4 points """
a1, a2, a3, a4 = Atom(), Atom(), Atom(), Atom()
a1.xx, a1.xy, a1.xz = 1, 0, 0
a2.xx, a2.xy, a2.xz = 0, 0, 0
a3.xx, a3.xy, a3.xz = 0, 0, 1
a4.xx, a4.xy, a4.xz = 0.1, 0.6, 1
self.assertAlmostEqual(geo.dihedral(a1, a2, a3, a4), 80.537677791974374)
self.assertAlmostEqual(
geo.dihedral([1, 0, 0], [0, 0, 0], [0, 0, 1], [0.1, 0.6, 1]),
80.537677791974374
)
def test_distance2(self):
""" Tests the distance2 calculation """
a1, a2 = Atom(), Atom()
a1.xx = a1.xy = a1.xz = 0
a2.xx = 3
a2.xy = 4
a2.xz = 0
self.assertEqual(geo.distance2(a1, a2), 25)
# Make sure it also works for tuples and a mixture of both
self.assertEqual(geo.distance2((0, 0, 0), (3, 4, 0)), 25)
self.assertEqual(geo.distance2(a1, (3, 4, 0)), 25)
self.assertEqual(geo.distance2((0, 0, 0), a2), 25)
def test_angle(self):
""" Tests the angle calculation """
a1, a2, a3 = Atom(), Atom(), Atom()
a1.xx = a1.xy = a1.xz = 0
a2.xx, a2.xy, a2.xz = 1, 0, 0
a3.xx, a3.xy, a3.xz = 1, 1, 0
self.assertAlmostEqual(geo.angle(a1, a2, a3), 90)
# Check pathological cases
a3.xx, a3.xy, a3.xz = 2, 0, 0
self.assertAlmostEqual(geo.angle(a1, a2, a3), 180)
a3.xx = a3.xy = a3.xz = 0
self.assertAlmostEqual(geo.angle(a1, a2, a3), 0)
def pdb4all2parmed(structure: 'PDB') -> 'Structure':
structure.guess_elements()
struc_pmd = Structure()
for a in structure.pdb:
atom = Atom(atomic_number=Ptable[a['element']]['N'],
name=a['name'],
number=a['serial'])
struc_pmd.add_atom(atom=atom,
resname=a['resName'],
resnum=a['resSeq'],
chain=a['chainID'],
segid=a['segment'])
struc_pmd.coordinates = structure.xyz
struc_pmd.assign_bonds()
return struc_pmd
def _parse_residue(fileobj, name):
"""
Parses the residue information out of the OFF file assuming the file
is pointed at the first line of an atoms table section of the OFF file
Parameters
----------
fileobj : file-like
Assumed to be open for read, this file is parsed until the *next*
atom table is read
name : str
The name of the residue being processed right now
"""
container = ResidueTemplateContainer(name)
nres = 1
templ = ResidueTemplate(name)
line = fileobj.readline()
while line[0] != '!':
nam, typ, typx, resx, flags, seq, elmnt, chg = line.split()
nam = _strip_enveloping_quotes(nam)
typ = _strip_enveloping_quotes(typ)
typx = int(typx)
resx = int(resx)
flags = int(flags)
seq = int(seq)
elmnt = int(elmnt)
chg = float(chg)
atom = Atom(atomic_number=elmnt, type=typ, name=nam, charge=chg)
if resx == nres + 1:
container.append(templ)
nres += 1
templ = ResidueTemplate(name)
templ.add_atom(atom)
line = fileobj.readline()
# Skip blank lines
while line and not line.strip():
line = fileobj.readline()
container.append(templ)
if nres > 1:
start_atoms = []
runsum = 0
for res in container:
start_atoms.append(runsum)
runsum += len(res)
# Make sure we get the next section
rematch = AmberOFFLibrary._sec2re.match(line)
if not rematch:
raise RuntimeError('Expected pertinfo table not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
line = fileobj.readline()
while line[0] != '!':
if not line:
raise RuntimeError('Unexpected EOF in Amber OFF library')
# Not used, just skip
# TODO sanity check
line = fileobj.readline()
rematch = AmberOFFLibrary._sec3re.match(line)
if not rematch:
raise RuntimeError('Expected boundbox table not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
# Only 5 lines
try:
hasbox = float(fileobj.readline().strip())
angle = float(fileobj.readline().strip())
a = float(fileobj.readline().strip())
b = float(fileobj.readline().strip())
c = float(fileobj.readline().strip())
except ValueError:
raise RuntimeError('Error processing boundbox table entries')
else:
if hasbox > 0:
if angle < 3.15:
# No box is this acute -- must be in radians
angle *= RAD_TO_DEG
container.box = [a, b, c, angle, angle, angle]
# Get the child sequence entry
line = fileobj.readline()
rematch = AmberOFFLibrary._sec4re.match(line)
if not rematch:
raise RuntimeError('Expected childsequence table not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
n = int(fileobj.readline().strip())
if nres + 1 != n:
warnings.warn('Unexpected childsequence (%d); expected %d for '
'residue %s' % (n, nres+1, name), AmberWarning)
elif not isinstance(templ, ResidueTemplate) and n != len(templ) + 1:
raise RuntimeError('child sequence must be 1 greater than the '
'number of residues in the unit')
# Get the CONNECT array to set head and tail
line = fileobj.readline()
rematch = AmberOFFLibrary._sec5re.match(line)
if not rematch:
raise RuntimeError('Expected connect array not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
try:
head = int(fileobj.readline().strip())
tail = int(fileobj.readline().strip())
except ValueError:
raise RuntimeError('Error processing connect table entries')
if head > 0 and nres == 1:
templ.head = templ[head-1]
elif head > 0 and nres > 1:
if head < sum((len(r) for r in container)):
raise RuntimeError('HEAD on multi-residue unit not supported')
if tail > 0 and nres == 1:
templ.tail = templ[tail-1]
elif tail > 0 and nres > 1:
if tail < sum((len(r) for r in container)):
warnings.warn('TAIL on multi-residue unit not supported (%s). '
'Ignored...' % name, AmberWarning)
# Get the connectivity array to set bonds
line = fileobj.readline()
if len(templ.atoms) > 1:
rematch = AmberOFFLibrary._sec6re.match(line)
if not rematch:
raise RuntimeError('Expected connectivity table not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
line = fileobj.readline()
while line[0] != '!':
i, j, flag = line.split()
line = fileobj.readline()
if nres > 1:
# Find which residue we belong in
i = int(i) - 1
j = int(j) - 1
for ii, idx in enumerate(start_atoms):
if idx > i:
ii -= 1
break
start_idx = start_atoms[ii]
container[ii].add_bond(i-start_idx, j-start_idx)
else:
templ.add_bond(int(i)-1, int(j)-1)
# Get the hierarchy table
rematch = AmberOFFLibrary._sec7re.match(line)
if not rematch:
raise RuntimeError('Expected hierarchy table not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
line = fileobj.readline()
while line[0] != '!':
# Skip this section... not used
# TODO turn this into a sanity check
line = fileobj.readline()
# Get the unit name
rematch = AmberOFFLibrary._sec8re.match(line)
if not rematch:
raise RuntimeError('Expected unit name string not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
fileobj.readline() # Skip this... not used
line = fileobj.readline()
# Get the atomic positions
rematch = AmberOFFLibrary._sec9re.match(line)
if not rematch:
raise RuntimeError('Expected unit positions table not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
for res in container:
for atom in res:
x, y, z = fileobj.readline().split()
atom.xx, atom.xy, atom.xz = float(x), float(y), float(z)
line = fileobj.readline()
# Get the residueconnect table
rematch = AmberOFFLibrary._sec10re.match(line)
if not rematch:
raise RuntimeError('Expected unit residueconnect table not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
for i in range(nres):
c1,c2,c3,c4,c5,c6 = (int(x) for x in fileobj.readline().split())
if (c1 > 0 and templ.head is not None and
templ.head is not templ[c1-1]):
raise RuntimeError('HEAD atom is not connect0')
if (c2 > 0 and templ.tail is not None and
templ.tail is not templ[c2-1]):
raise RuntimeError('TAIL atom is not connect1')
for i in (c3, c4, c5, c6):
if i == 0: continue
templ.connections.append(templ[i-1])
# Get the residues table
line = fileobj.readline()
rematch = AmberOFFLibrary._sec11re.match(line)
if not rematch:
raise RuntimeError('Expected unit residues table not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
for i in range(nres):
resname, id, next, start, typ, img = fileobj.readline().split()
resname = _strip_enveloping_quotes(resname)
id = int(id)
start = int(start)
next = int(next)
typ = _strip_enveloping_quotes(typ)
img = int(img)
if next - start != len(container[i]):
warnings.warn('residue table predicted %d, not %d atoms for '
'residue %s' % (next-start, len(container[i]),
name), AmberWarning)
if typ == 'p':
container[i].type = PROTEIN
elif typ == 'n':
container[i].type = NUCLEIC
elif typ == 'w':
container[i].type = SOLVENT
elif typ != '?':
warnings.warn('Unknown residue type "%s"' % typ, AmberWarning)
if nres > 1:
container[i].name = resname
# Get the residues sequence table
line = fileobj.readline()
rematch = AmberOFFLibrary._sec12re.match(line)
if not rematch:
raise RuntimeError('Expected residue sequence number not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
for i in range(nres):
#TODO sanity check
fileobj.readline()
line = fileobj.readline()
# Get the solventcap array
rematch = AmberOFFLibrary._sec13re.match(line)
if not rematch:
raise RuntimeError('Expected unit solventcap array not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
# Ignore the solvent cap
fileobj.readline()
fileobj.readline()
fileobj.readline()
fileobj.readline()
fileobj.readline()
# Velocities
line = fileobj.readline()
rematch = AmberOFFLibrary._sec14re.match(line)
if not rematch:
raise RuntimeError('Expected unit solventcap array not found')
elif rematch.groups()[0] != name:
raise RuntimeError('Found residue %s while processing residue %s' %
(rematch.groups()[0], name))
for res in container:
for atom in res:
vx, vy, vz = (float(x) for x in fileobj.readline().split())
atom.vx, atom.vy, atom.vz = vx, vy, vz
if nres > 1:
return container
return templ
