def measBeta(elem, dqk1=0.01, full=False, num_points=3, verbose=0):
"""
Measure the beta function by varying quadrupole strength
Parameters
-----------
elem : element name, name list or pattern.
dqk1 : float. the quadrupole change range [-dqk1, dqk1]
full : bool. returns more data besides beta
num_points : int. points in [-dqk1, dqk1] to fit the line, default 3.
verbose : verbose
Returns
--------
beta : numpy array (N_elements, 3). fitted betax, betay and s_center
k1, nu : optional. present only if *full*=True.
k1 is numpy array (N_elements, num_points), quadrupole settings. nu is
numpy array (N_elements, num_points, 2). tunes.
Notes
------
see `getElements` for acceptable *elem* format. Some users prefer using
turn-by-turn BPM data to calculate the beta functions
"""
elems = getElements(elem)
if elems is None:
raise ValueError("can not find element '%s'" % elem)
if verbose:
print("# fitting %d quadrupoles:" % len(elems))
print("# " + ' '.join([q.name for q in elems]))
kwargs = {'dqk1': dqk1, 'num_points': num_points, 'verbose': verbose}
nux, nuy = getTunes()
nu = np.zeros((len(elems), num_points, 2), 'd')
k1 = np.zeros((len(elems), num_points), 'd')
beta = np.zeros((len(elems), 3), 'd')
for i, q in enumerate(elems):
beta[i, -1] = (q.sb + q.se) / 2.0
# is an element
k1[i, :], nu[i, :, :] = _measBetaQuad(q, **kwargs)
if verbose:
print(i, q.name, q.k1, end=" ")
p, res, rank, sv, rcond = np.polyfit(k1[i, :],
nu[i, :, :],
deg=1,
full=True)
# p[0,k] is the highest power for dataset k
beta[i, :2] = p[0, :] * 4 * np.pi / q.length
# reverse the k1 for vertical direction
beta[i, 1] = -beta[i, 1]
print(q.sb, q.name, beta[i, 0], beta[i, 1], p[0, :])
if full: return beta, k1, nu
else: return beta
def measBeta(elem, dqk1=0.01, full=False, num_points=3, verbose=0):
"""
Measure the beta function by varying quadrupole strength
Parameters
-----------
elem : element name, name list or pattern.
dqk1 : float. the quadrupole change range [-dqk1, dqk1]
full : bool. returns more data besides beta
num_points : int. points in [-dqk1, dqk1] to fit the line, default 3.
verbose : verbose
Returns
--------
beta : numpy array (N_elements, 3). fitted betax, betay and s_center
k1, nu : optional. present only if *full*=True.
k1 is numpy array (N_elements, num_points), quadrupole settings. nu is
numpy array (N_elements, num_points, 2). tunes.
Notes
------
see `getElements` for acceptable *elem* format. Some users prefer using
turn-by-turn BPM data to calculate the beta functions
"""
elems = getElements(elem)
if elems is None:
raise ValueError("can not find element '%s'" % elem)
if verbose:
print("# fitting %d quadrupoles:" % len(elems))
print("# " + " ".join([q.name for q in elems]))
kwargs = {"dqk1": dqk1, "num_points": num_points, "verbose": verbose}
nux, nuy = getTunes()
nu = np.zeros((len(elems), num_points, 2), "d")
k1 = np.zeros((len(elems), num_points), "d")
beta = np.zeros((len(elems), 3), "d")
for i, q in enumerate(elems):
beta[i, -1] = (q.sb + q.se) / 2.0
# is an element
k1[i, :], nu[i, :, :] = _measBetaQuad(q, **kwargs)
if verbose:
print(i, q.name, q.k1, end=" ")
p, res, rank, sv, rcond = np.polyfit(k1[i, :], nu[i, :, :], deg=1, full=True)
# p[0,k] is the highest power for dataset k
beta[i, :2] = p[0, :] * 4 * np.pi / q.length
# reverse the k1 for vertical direction
beta[i, 1] = -beta[i, 1]
print(q.sb, q.name, beta[i, 0], beta[i, 1], p[0, :])
if full:
return beta, k1, nu
else:
return beta
def _measBetaQuad(elem, **kwargs):
dqk1 = abs(kwargs.get("dqk1", 0.01))
num_points = kwargs.get("num_points", 5)
minwait = kwargs.get("minwait", 3)
qk10 = elem.k1
qk1 = qk10 + np.linspace(-dqk1, dqk1, num_points)
nu = np.zeros((num_points, 2), "d")
for i, k1 in enumerate(qk1):
v0 = getOrbit()
elem.k1 = k1
waitStableOrbit(v0, minwait=minwait, maxwait=15)
nu[i, :] = getTunes()
elem.k1 = qk10
return qk1, nu
def _measBetaQuad(elem, **kwargs):
dqk1 = abs(kwargs.get('dqk1', 0.01))
num_points = kwargs.get('num_points', 5)
minwait = kwargs.get('minwait', 3)
qk10 = elem.k1
qk1 = qk10 + np.linspace(-dqk1, dqk1, num_points)
nu = np.zeros((num_points, 2), 'd')
for i, k1 in enumerate(qk1):
v0 = getOrbit()
elem.k1 = k1
waitStableOrbit(v0, minwait=minwait, maxwait=15)
nu[i, :] = getTunes()
elem.k1 = qk10
return qk1, nu
def _measChromaticity(**kwargs):
"""Measure the chromaticity
Parameters
-----------
dfmax - max RF frequency change (within plus/minus), 1e-6
gamma - beam, 3.0/0.511e-3
alphac - momentum compaction factor, 3.62619e-4
wait - 1.5 second
num_points - 5
returns dp/p, nu, chrom
dpp - dp/p energy deviation
nu - tunes
chrom - result chromaticities
obt - orbit at each f settings (initial, every df, final).
"""
dfmax = kwargs.get("dfmax", 1e-6)
gamma = kwargs.get("gamma", 3.0e3 / 0.511)
alphac = kwargs.get("alphac", 3.6261976841792413e-04)
wait = kwargs.get("wait", 1.5)
npt = kwargs.get("num_points", 5)
verbose = kwargs.get("verbose", 0)
eta = alphac - 1 / gamma / gamma
obt = []
f0 = getRfFrequency(handle="setpoint")
nu0 = getTunes()
obt.append(getOrbit(spos=True))
_logger.info("Initial RF freq= {0}, tunes= {1}" % (f0, nu0))
# incase RF does not allow large step change, ramp down first
if verbose:
print("Initial RF freq= {0}, stepping down {1} in {2} steps".format(f0, -dfmax, npt))
for df in np.linspace(0, abs(dfmax), npt)[1:-1]:
putRfFrequency(f0 - df)
time.sleep(2.0 / npt)
f = np.linspace(f0 - dfmax, f0 + dfmax, npt)
nu = np.zeros((len(f), 2), "d")
for i, f1 in enumerate(f):
if verbose > 0:
print("freq= ", f1, end=" ")
putRfFrequency(f1)
time.sleep(wait)
nu[i, :] = getTunes()
obt.append(getOrbit(spos=True))
if verbose > 0:
print(
"tunes:",
nu[i, 0],
nu[i, 1],
np.min(obt[-1][:, 0]),
np.max(obt[-1][:, 0]),
np.min(obt[-1][:, 1]),
np.max(obt[-1][:, 1]),
)
for df in np.linspace(0, abs(dfmax), npt):
putRfFrequency(f0 + abs(dfmax) - df)
time.sleep(2.0 / npt)
obt.append(getOrbit(spos=True))
df = f - f0
dnu = nu - np.array(nu0)
p, resi, rank, sing, rcond = np.polyfit(df, dnu, deg=2, full=True)
chrom = p[-2, :] * (-f0 * eta)
if verbose > 0:
print("Coef:", p)
print("Resi:", resi)
print("Chrom:", chrom)
return df / (-f0 * eta), nu, chrom, obt
def measChromaticity(
dfmax=1e-6, gamma=3.0e3 / 0.511, alphac=3.626e-4, num_points=5, fMeasTunes=None, deg=2, wait=0.5, verbose=0
):
"""Measure the chromaticity
Parameters
-----------
dfmax - max RF frequency change (within plus/minus), 1e-6
gamma - beam, 3.0/0.511e-3
alphac - momentum compaction factor, 3.62619e-4
wait - 1.5 second
num_points - 5
fMeasTunes - function used to get tunes. default None, use getTunes().
returns
--------
chrom : chromaticity, (chx, chy)
info : dictionary
freq : list of frequency setting
freq0 : initial frequency setpoint
tune : list of tunes, shape (num_points, 2)
dpp : dp/p energy deviation
obt : orbit at each f settings (initial, every df, final).
deg : degree of polynomial fitting.
p : polynomial coeff, shape (deg+1, 2)
"""
obt = []
f0 = getRfFrequency(handle="setpoint")
# names, x0, y0, Isum0, timestamp, offset = \
# measKickedTbtData(7, (0.15, 0.2), sleep=10, output=False)
# nu0 = (calcFftTunes(x0), calcFftTunes(y0))
nu0 = fMeasTunes() if fMeasTunes else getTunes()
obt.append(getOrbit(spos=True))
# _logger.info("Initial RF freq= {0}, tunes= {1}" % (f0, nu0))
# incase RF does not allow large step change, ramp down first
if verbose:
print("Initial RF freq= {0}, stepping down {1} in {2} steps".format(f0, -dfmax, num_points))
for df in np.linspace(0, abs(dfmax), num_points)[1:-1]:
putRfFrequency(f0 - df)
time.sleep(2.0 / num_points)
f = np.linspace(f0 - dfmax, f0 + dfmax, num_points)
nu = np.zeros((len(f), 2), "d")
for i, f1 in enumerate(f):
if verbose > 0:
print("dfreq= {0: .2e}".format(f1 - f0), end=" ")
putRfFrequency(f1)
time.sleep(wait)
nu[i, :] = fMeasTunes() if fMeasTunes else getTunes()
obt.append(getOrbit(spos=True))
if verbose > 0:
print(
"tunes: {0:.5f} {1:.5f}".format(nu[i, 0], nu[i, 1]),
"orbit min-max: {0:.2e} {1:.2e}, {2:.2e} {3:.2e}".format(
np.min(obt[-1][:, 0]), np.max(obt[-1][:, 0]), np.min(obt[-1][:, 1]), np.max(obt[-1][:, 1])
),
)
for df in np.linspace(0, abs(dfmax), num_points):
putRfFrequency(f0 + abs(dfmax) - df)
time.sleep(2.0 / num_points)
obt.append(getOrbit(spos=True))
# calculate chrom, return info
info = {"freq": f, "tune": nu, "orbit": obt, "freq0": f0, "deg": deg}
chrom, dpp, p = calcChromaticity(f0, f, nu, deg=deg)
info["dpp"] = dpp
info["p"] = p
return chrom, info
def _measChromaticity(**kwargs):
"""Measure the chromaticity
Parameters
-----------
dfmax - max RF frequency change (within plus/minus), 1e-6
gamma - beam, 3.0/0.511e-3
alphac - momentum compaction factor, 3.62619e-4
wait - 1.5 second
num_points - 5
returns dp/p, nu, chrom
dpp - dp/p energy deviation
nu - tunes
chrom - result chromaticities
obt - orbit at each f settings (initial, every df, final).
"""
dfmax = kwargs.get("dfmax", 1e-6)
gamma = kwargs.get("gamma", 3.0e3 / .511)
alphac = kwargs.get("alphac", 3.6261976841792413e-04)
wait = kwargs.get("wait", 1.5)
npt = kwargs.get("num_points", 5)
verbose = kwargs.get("verbose", 0)
eta = alphac - 1 / gamma / gamma
obt = []
f0 = getRfFrequency(handle="setpoint")
nu0 = getTunes()
obt.append(getOrbit(spos=True))
_logger.info("Initial RF freq= {0}, tunes= {1}" % (f0, nu0))
# incase RF does not allow large step change, ramp down first
if verbose:
print("Initial RF freq= {0}, stepping down {1} in {2} steps".format(
f0, -dfmax, npt))
for df in np.linspace(0, abs(dfmax), npt)[1:-1]:
putRfFrequency(f0 - df)
time.sleep(2.0 / npt)
f = np.linspace(f0 - dfmax, f0 + dfmax, npt)
nu = np.zeros((len(f), 2), 'd')
for i, f1 in enumerate(f):
if verbose > 0:
print("freq= ", f1, end=" ")
putRfFrequency(f1)
time.sleep(wait)
nu[i, :] = getTunes()
obt.append(getOrbit(spos=True))
if verbose > 0:
print("tunes:", nu[i, 0], nu[i, 1], np.min(obt[-1][:, 0]),
np.max(obt[-1][:, 0]), np.min(obt[-1][:, 1]),
np.max(obt[-1][:, 1]))
for df in np.linspace(0, abs(dfmax), npt):
putRfFrequency(f0 + abs(dfmax) - df)
time.sleep(2.0 / npt)
obt.append(getOrbit(spos=True))
df = f - f0
dnu = nu - np.array(nu0)
p, resi, rank, sing, rcond = np.polyfit(df, dnu, deg=2, full=True)
chrom = p[-2, :] * (-f0 * eta)
if verbose > 0:
print("Coef:", p)
print("Resi:", resi)
print("Chrom:", chrom)
return df / (-f0 * eta), nu, chrom, obt
def measChromaticity(dfmax=1e-6,
gamma=3.0e3 / 0.511,
alphac=3.626e-4,
num_points=5,
fMeasTunes=None,
deg=2,
wait=0.5,
verbose=0):
"""Measure the chromaticity
Parameters
-----------
dfmax - max RF frequency change (within plus/minus), 1e-6
gamma - beam, 3.0/0.511e-3
alphac - momentum compaction factor, 3.62619e-4
wait - 1.5 second
num_points - 5
fMeasTunes - function used to get tunes. default None, use getTunes().
returns
--------
chrom : chromaticity, (chx, chy)
info : dictionary
freq : list of frequency setting
freq0 : initial frequency setpoint
tune : list of tunes, shape (num_points, 2)
dpp : dp/p energy deviation
obt : orbit at each f settings (initial, every df, final).
deg : degree of polynomial fitting.
p : polynomial coeff, shape (deg+1, 2)
"""
obt = []
f0 = getRfFrequency(handle="setpoint")
#names, x0, y0, Isum0, timestamp, offset = \
# measKickedTbtData(7, (0.15, 0.2), sleep=10, output=False)
#nu0 = (calcFftTunes(x0), calcFftTunes(y0))
nu0 = fMeasTunes() if fMeasTunes else getTunes()
obt.append(getOrbit(spos=True))
#_logger.info("Initial RF freq= {0}, tunes= {1}" % (f0, nu0))
# incase RF does not allow large step change, ramp down first
if verbose:
print("Initial RF freq= {0}, stepping down {1} in {2} steps".format(
f0, -dfmax, num_points))
for df in np.linspace(0, abs(dfmax), num_points)[1:-1]:
putRfFrequency(f0 - df)
time.sleep(2.0 / num_points)
f = np.linspace(f0 - dfmax, f0 + dfmax, num_points)
nu = np.zeros((len(f), 2), 'd')
for i, f1 in enumerate(f):
if verbose > 0:
print("dfreq= {0: .2e}".format(f1 - f0), end=" ")
putRfFrequency(f1)
time.sleep(wait)
nu[i, :] = fMeasTunes() if fMeasTunes else getTunes()
obt.append(getOrbit(spos=True))
if verbose > 0:
print(
"tunes: {0:.5f} {1:.5f}".format(nu[i, 0], nu[i, 1]),
"orbit min-max: {0:.2e} {1:.2e}, {2:.2e} {3:.2e}".format(
np.min(obt[-1][:, 0]), np.max(obt[-1][:, 0]),
np.min(obt[-1][:, 1]), np.max(obt[-1][:, 1])))
for df in np.linspace(0, abs(dfmax), num_points):
putRfFrequency(f0 + abs(dfmax) - df)
time.sleep(2.0 / num_points)
obt.append(getOrbit(spos=True))
# calculate chrom, return info
info = {"freq": f, "tune": nu, "orbit": obt, "freq0": f0, "deg": deg}
chrom, dpp, p = calcChromaticity(f0, f, nu, deg=deg)
info["dpp"] = dpp
info["p"] = p
return chrom, info
