def test_snapshotKeplerPotential_zforce_naz():
# Set up a snapshot with just one unit mass at the origin
s= pynbody.new(star=1)
s['mass']= 1.
s['eps']= 0.
sp= potential.SnapshotRZPotential(s,num_threads=1)
spaz= potential.SnapshotRZPotential(s,num_threads=1,nazimuths=12)
assert numpy.fabs(sp.zforce(1.,0.)-spaz.zforce(1.,0.)) < 10.**-8., 'SnapshotRZPotential with single unit mass for naz=4 does not agree with naz=12'
assert numpy.fabs(sp.zforce(0.5,0.)-spaz.zforce(0.5,0.)) < 10.**-8., 'SnapshotRZPotential with single unit mass for naz=4 does not agree with naz=12'
assert numpy.fabs(sp.zforce(1.,0.5)-spaz.zforce(1.,0.5)) < 10.**-8., 'SnapshotRZPotential with single unit mass for naz=4 does not agree with naz=12'
assert numpy.fabs(sp.zforce(1.,-0.5)-spaz.zforce(1.,-0.5)) < 10.**-8., 'SnapshotRZPotential with single unit mass for naz=4 does not agree with naz=12'
return None
def test_snapshotrzpotential_nopynbody():
# Test that if we cannot load pynbody, we get an ImportError
from galpy.potential_src import SnapshotRZPotential
SnapshotRZPotential._PYNBODY_LOADED= False
try:
sp= potential.SnapshotRZPotential(1.) #1. doesn't matter
except ImportError: pass
else:
raise AssertionError("SnapshotRZPotential w/o pynbody should have raised an error, but didn't")
return None
def test_snapshotKeplerPotential_hash():
# Test that hashing the previous grid works
# Set up a snapshot with just one unit mass at the origin
s= pynbody.new(star=1)
s['mass']= 1.
s['eps']= 0.
sp= potential.SnapshotRZPotential(s)
kp= potential.KeplerPotential(amp=1.) #should be the same
assert numpy.fabs(sp(1.,0.)-kp(1.,0.)) < 10.**-8., 'SnapshotRZPotential with single unit mass does not correspond to KeplerPotential'
assert numpy.fabs(sp(1.,0.)-kp(1.,0.)) < 10.**-8., 'SnapshotRZPotential with single unit mass does not correspond to KeplerPotential'
return None
def test_snapshotKeplerPotential_zforce_array():
# Test evaluating the snapshotPotential with array input
# Set up a snapshot with just one unit mass at the origin
s= pynbody.new(star=1)
s['mass']= 1.
s['eps']= 0.
sp= potential.SnapshotRZPotential(s)
kp= potential.KeplerPotential(amp=1.) #should be the same
rs= numpy.ones(3)*0.5+0.5
zs= (numpy.zeros(3)-1.)/2.
assert numpy.all(numpy.fabs(sp.zforce(rs,zs)-kp.zforce(rs,zs)) < 10.**-8.), 'SnapshotRZPotential with single unit mass does not correspond to KeplerPotential'
return None
def test_snapshotKeplerPotential_grid():
# Test that evaluating on a grid works
# Set up a snapshot with just one unit mass at the origin
s= pynbody.new(star=1)
s['mass']= 2.
s['eps']= 0.
sp= potential.SnapshotRZPotential(s)
kp= potential.KeplerPotential(amp=2.) #should be the same
rs= numpy.arange(3)+1
zs= 0.1
assert numpy.all(numpy.fabs(sp(rs,zs)-kp(rs,zs)) < 10.**-8.), 'SnapshotRZPotential with single unit mass does not correspond to KeplerPotential'
return None
def test_snapshotKeplerPotential_eval():
# Set up a snapshot with just one unit mass at the origin
s= pynbody.new(star=1)
s['mass']= 1.
s['eps']= 0.
sp= potential.SnapshotRZPotential(s,num_threads=1)
kp= potential.KeplerPotential(amp=1.) #should be the same
assert numpy.fabs(sp(1.,0.)-kp(1.,0.)) < 10.**-8., 'SnapshotRZPotential with single unit mass does not correspond to KeplerPotential'
assert numpy.fabs(sp(0.5,0.)-kp(0.5,0.)) < 10.**-8., 'SnapshotRZPotential with single unit mass does not correspond to KeplerPotential'
assert numpy.fabs(sp(1.,0.5)-kp(1.,0.5)) < 10.**-8., 'SnapshotRZPotential with single unit mass does not correspond to KeplerPotential'
assert numpy.fabs(sp(1.,-0.5)-kp(1.,-0.5)) < 10.**-8., 'SnapshotRZPotential with single unit mass does not correspond to KeplerPotential'
return None