def fitCD( f, Z, p0, Cgeom=Cgeom ):
""" find the capacitance and loss of a set of data (in f,Z form, where Z is complex)
and fit this with Ashoori's model to find fpeak, Clow, Chigh, and the conductivity G
fpeak, Clow, Chigh, G = fitCD( f, Z, p0, Cgeom=80.0 )
where
p0 = [fpeak0, Clow0, Chigh0] # initial guesses
"""
lsq = fmin_plain( sumresidualsCD, p0, args=(Z, f), ftol=1e-8, xtol=1e-8, maxfun=2000, disp=False )
fpeak, Clow, Chigh = abs(lsq)
G = 2*pi*fpeak*Cgeom**2/sqrt(Clow*Chigh)*(Clow/Chigh - 1) * 1e-12 # see Eq. 2 of Ashoori's PRB
return fpeak, Clow, Chigh, G
def fitZ( f, Zdata, p0, pfixed ):
""" find the capacitance and loss of a set of data (in f,Z form, where Z is complex)
and fit this with Ashoori's model to find fpeak, Clow, Chigh, and the conductivity G
Ctj, Cq, tau = fitZ( f, Zdata, p0, pfixed )
where
p0 = [Ctj0, Cq0, tau0] # initial guesses
pfixed = [Cg, Cbp, Rs, Rp] # fixed parameters
"""
lsq = fmin_plain( sumresidualsZ, p0, args=(pfixed, Zdata, f), ftol=1e-8, xtol=1e-8, maxfun=2000, disp=False )
if len(pfixed) == 4:
Ctj, Cq, tau = abs(lsq)
return Ctj, Cq, tau
elif len(pfixed) == 5:
Cq, tau = abs(lsq)
return Cq, tau
else:
print "shit! wrong number fixed params to fitZ"
return None
def fitCD(f, Z, p0, Cgeom=Cgeom):
""" find the capacitance and loss of a set of data (in f,Z form, where Z is complex)
and fit this with Ashoori's model to find fpeak, Clow, Chigh, and the conductivity G
fpeak, Clow, Chigh, G = fitCD( f, Z, p0, Cgeom=80.0 )
where
p0 = [fpeak0, Clow0, Chigh0] # initial guesses
"""
lsq = fmin_plain(sumresidualsCD,
p0,
args=(Z, f),
ftol=1e-8,
xtol=1e-8,
maxfun=2000,
disp=False)
fpeak, Clow, Chigh = abs(lsq)
G = 2 * pi * fpeak * Cgeom**2 / sqrt(Clow * Chigh) * (
Clow / Chigh - 1) * 1e-12 # see Eq. 2 of Ashoori's PRB
return fpeak, Clow, Chigh, G
def fitZ(f, Zdata, p0, pfixed):
""" find the capacitance and loss of a set of data (in f,Z form, where Z is complex)
and fit this with Ashoori's model to find fpeak, Clow, Chigh, and the conductivity G
Ctj, Cq, tau = fitZ( f, Zdata, p0, pfixed )
where
p0 = [Ctj0, Cq0, tau0] # initial guesses
pfixed = [Cg, Cbp, Rs, Rp] # fixed parameters
"""
lsq = fmin_plain(sumresidualsZ,
p0,
args=(pfixed, Zdata, f),
ftol=1e-8,
xtol=1e-8,
maxfun=2000,
disp=False)
if len(pfixed) == 4:
Ctj, Cq, tau = abs(lsq)
return Ctj, Cq, tau
elif len(pfixed) == 5:
Cq, tau = abs(lsq)
return Cq, tau
else:
print "shit! wrong number fixed params to fitZ"
return None