lattice/pyerrors
1
0
Fork 0
mirror of https://github.com/fjosw/pyerrors.git synced 2025-05-15 20:13:41 +02:00
Code Issues Projects Releases Packages Wiki Activity

feat!: Implemented improved first and second derivatives for the

Browse source 
corresponding methods of the Corr class. The parameter which
distinguishes between the variant is now a string instead of a bool
which may break current analyses.
This commit is contained in:
Fabian Joswig 2022-01-31 10:50:00 +00:00
parent fbb98e05f6
commit 8165479846
2 changed files with 75 additions and 30 deletions
Download patch file Download diff file Expand all files Collapse all files

83
pyerrors/correlators.py
View file

@ -460,25 +460,16 @@ class Corr:
return (self + T_partner) / 2
def deriv(self, symmetric=True):
def deriv(self, variant="symmetric"):
"""Return the first derivative of the correlator with respect to x0.
Parameters
----------
symmetric : bool
decides whether symmetric of simple finite differences are used. Default: True
variant : str
decides which definition of the finite differences derivative is used.
Available choice: symmetric, forward, improved, default: symmetric
"""
if not symmetric:
newcontent = []
for t in range(self.T - 1):
if (self.content[t] is None) or (self.content[t + 1] is None):
newcontent.append(None)
else:
newcontent.append(self.content[t + 1] - self.content[t])
if(all([x is None for x in newcontent])):
raise Exception("Derivative is undefined at all timeslices")
return Corr(newcontent, padding=[0, 1])
if symmetric:
if variant == "symmetric":
newcontent = []
for t in range(1, self.T - 1):
if (self.content[t - 1] is None) or (self.content[t + 1] is None):
@ -488,18 +479,60 @@ class Corr:
if(all([x is None for x in newcontent])):
raise Exception('Derivative is undefined at all timeslices')
return Corr(newcontent, padding=[1, 1])
elif variant == "forward":
newcontent = []
for t in range(self.T - 1):
if (self.content[t] is None) or (self.content[t + 1] is None):
newcontent.append(None)
else:
newcontent.append(self.content[t + 1] - self.content[t])
if(all([x is None for x in newcontent])):
raise Exception("Derivative is undefined at all timeslices")
return Corr(newcontent, padding=[0, 1])
elif variant == "improved":
newcontent = []
for t in range(2, self.T - 2):
if (self.content[t - 2] is None) or (self.content[t - 1] is None) or (self.content[t + 1] is None) or (self.content[t + 2] is None):
newcontent.append(None)
else:
newcontent.append((1 / 12) * (self.content[t - 2] - 8 * self.content[t - 1] + 8 * self.content[t + 1] - self.content[t + 2]))
if(all([x is None for x in newcontent])):
raise Exception('Derivative is undefined at all timeslices')
return Corr(newcontent, padding=[2, 2])
else:
raise Exception("Unknown variant.")
def second_deriv(self):
"""Return the second derivative of the correlator with respect to x0."""
newcontent = []
for t in range(1, self.T - 1):
if (self.content[t - 1] is None) or (self.content[t + 1] is None):
newcontent.append(None)
else:
newcontent.append((self.content[t + 1] - 2 * self.content[t] + self.content[t - 1]))
if(all([x is None for x in newcontent])):
raise Exception("Derivative is undefined at all timeslices")
return Corr(newcontent, padding=[1, 1])
def second_deriv(self, variant="symmetric"):
"""Return the second derivative of the correlator with respect to x0.
Parameters
----------
variant : str
decides which definition of the finite differences derivative is used.
Available choice: symmetric, improved, default: symmetric
"""
if variant == "symmetric":
newcontent = []
for t in range(1, self.T - 1):
if (self.content[t - 1] is None) or (self.content[t + 1] is None):
newcontent.append(None)
else:
newcontent.append((self.content[t + 1] - 2 * self.content[t] + self.content[t - 1]))
if(all([x is None for x in newcontent])):
raise Exception("Derivative is undefined at all timeslices")
return Corr(newcontent, padding=[1, 1])
elif variant == "improved":
newcontent = []
for t in range(2, self.T - 2):
if (self.content[t - 2] is None) or (self.content[t - 1] is None) or (self.content[t] is None) or (self.content[t + 1] is None) or (self.content[t + 2] is None):
newcontent.append(None)
else:
newcontent.append((1 / 12) * (-self.content[t + 2] + 16 * self.content[t + 1] - 30 * self.content[t] + 16 * self.content[t - 1] - self.content[t - 2]))
if(all([x is None for x in newcontent])):
raise Exception("Derivative is undefined at all timeslices")
return Corr(newcontent, padding=[2, 2])
else:
raise Exception("Unknown variant.")
def m_eff(self, variant='log', guess=1.0):
"""Returns the effective mass of the correlator as correlator object