def test_checktype(simple_ring):
assert checktype(elements.Drift)(simple_ring[0]) is True
assert checktype(elements.Marker)(simple_ring[0]) is False
assert (list(filter(checktype(elements.Drift), simple_ring)) == [
simple_ring[0], simple_ring[3], simple_ring[4], simple_ring[5]
])
assert list(filter(checktype(elements.Monitor), simple_ring)) == []
def set_cavity_phase(ring,
method=ELossMethod.INTEGRAL,
refpts=None,
cavpts=None,
copy=False):
"""
Adjust the TimeLag attribute of RF cavities based on frequency,
voltage and energy loss per turn, so that the synchronous phase is zero.
An error occurs if all cavities do not have the same frequency.
!!!!WARNING!!!: This function changes the time reference, this should be
avoided
PARAMETERS
ring lattice description
KEYWORDS
method=ELossMethod.INTEGRAL
method for energy loss computation.
See "get_energy_loss".
cavpts=None Cavity location. If None, use all cavities.
This allows to ignore harmonic cavities.
copy=False If True, returns a shallow copy of ring with new
cavity elements. Otherwise, modify ring in-place.
"""
# refpts is kept for backward compatibility
if cavpts is None and refpts is not None:
warn(FutureWarning('You should use "cavpts" instead of "refpts"'))
cavpts = refpts
elif cavpts is None:
cavpts = get_cells(ring, checktype(RFCavity))
timelag, ts = get_timelag_fromU0(ring, method=method, cavpts=cavpts)
set_value_refpts(ring, cavpts, 'TimeLag', timelag, copy=copy)
def get_timelag_fromU0(ring, method=ELossMethod.INTEGRAL, cavpts=None):
"""
Get the TimeLag attribute of RF cavities based on frequency,
voltage and energy loss per turn, so that the synchronous phase is zero.
An error occurs if all cavities do not have the same frequency.
Used in set_cavity_phase()
PARAMETERS
ring lattice description
KEYWORDS
method=ELossMethod.INTEGRAL
method for energy loss computation.
See "get_energy_loss".
cavpts=None Cavity location. If None, use all cavities.
This allows to ignore harmonic cavities.
RETURN
timelag
"""
if cavpts is None:
cavpts = get_cells(ring, checktype(RFCavity))
u0 = get_energy_loss(ring, method=method)
try:
rfv = ring.get_rf_voltage(cavpts=cavpts)
freq = ring.get_rf_frequency(cavpts=cavpts)
tl0 = ring.get_rf_timelag(cavpts=cavpts)
except AtError:
freq = numpy.array([cav.Frequency for cav in ring.select(cavpts)])
rfv = numpy.array([cav.Voltage for cav in ring.select(cavpts)])
tl0 = numpy.array([cav.TimeLag for cav in ring.select(cavpts)])
if u0 > numpy.sum(rfv):
raise AtError('Not enough RF voltage: unstable ring')
ctmax = 1 / numpy.amin(freq) * clight / 2
tt0 = tl0[numpy.argmin(freq)]
eq = lambda x: numpy.sum(rfv * numpy.sin(2 * pi * freq *
(x + tl0) / clight)) - u0
deq = lambda x: numpy.sum(rfv * numpy.cos(2 * pi * freq *
(x + tl0) / clight))
zero_diff = least_squares(deq,
-tt0 + ctmax / 2,
bounds=(-tt0, ctmax - tt0)).x[0]
if numpy.sign(deq(zero_diff - 1.0e-6)) > 0:
ts = least_squares(eq, (zero_diff - tt0) / 2,
bounds=(-tt0, zero_diff)).x[0]
else:
ts = least_squares(eq, (ctmax - tt0 + zero_diff) / 2,
bounds=(zero_diff, ctmax - tt0)).x[0]
timelag = ts + tl0
else:
if u0 > rfv:
raise AtError('Not enough RF voltage: unstable ring')
timelag = clight / (2 * pi * freq) * numpy.arcsin(u0 / rfv)
ts = timelag - tl0
timelag *= numpy.ones(refpts_len(ring, cavpts))
return timelag, ts
def set_cavity(ring,
Voltage=None,
Frequency=None,
HarmNumber=None,
TimeLag=None,
cavpts=None,
copy=False):
"""
PARAMETERS
ring lattice description
KEYWORDS
Frequency=None RF frequency. The special enum value Frf.NOMINAL
sets the frequency to the nominal value, given
ring length and harmonic number.
Voltage=None RF voltage for the full ring.
HarmNumber=None Harmonic number for the full ring.
TimeLag=None
cavpts=None Cavity location. If None, use all cavities.
This allows to ignore harmonic cavities.
copy=False If True, returns a shallow copy of ring with new
cavity elements. Otherwise, modify ring in-place
"""
def get_harm(hcell):
if hcell is not None:
return hcell * n_periods
else:
return ring.get_rf_harmonic_number(cavpts=cavpts)
if cavpts is None:
cavpts = get_cells(ring, checktype(elements.RFCavity))
n_cavities = ring.refcount(cavpts)
if n_cavities < 1:
raise AtError('No cavity found in the lattice')
n_periods = ring.periodicity
modif = {}
if Frequency is not None:
if Frequency is Frf.NOMINAL:
Frequency = (clight / ring.circumference) * get_harm(HarmNumber)
modif['Frequency'] = Frequency
if HarmNumber is not None:
modif['HarmNumber'] = HarmNumber / n_periods
if TimeLag is not None:
modif['TimeLag'] = TimeLag
if Voltage is not None:
modif['Voltage'] = Voltage / n_periods / n_cavities
# noinspection PyShadowingNames
@make_copy(copy)
def apply(ring, cavpts, modif):
for cavity in ring.select(cavpts):
cavity.update(modif)
return apply(ring, cavpts, modif)
def _get_rf_attr(ring, attr, cavpts=None):
if cavpts is None:
cavpts = checktype(elements.RFCavity)
cavities = ring.select(cavpts)
return numpy.array([getattr(cavity, attr) for cavity in cavities])