This module contains tools for least-squares fits, as functions
of time t, of simulation (or other statistical) data for 2-point and
3-point correlators of the form:
Gab(t) = <b(t) a(0)> Gavb(t,T) = <b(T) V(t) a(0)>
Each correlator is modeled using Corr2 for 2-point correlators, or
Corr3 for 3-point correlators in terms of amplitudes for each source
a, sink b, and vertex V, and the energies associated with each
intermediate state. The amplitudes and energies are adjusted in the
least-squares fit to reproduce the data; they are specified in a shared prior
(typically a dictionary).
An object of type CorrFitter describes a collection of correlators and is
used to fit multiple models to data simultaneously. Any number of
correlators may be described and fit by a single CorrFitter object.
CorrFitter objects can also be used to to extract the appropriate fit
data from Dataset objects.
This module has been used extensively for analyzing results from lattice QCD
simulations. Documentation for this module can be found by looking at
doc/html/index.html or <https://corrfitter.readthedocs.io>. The .py
files in directory examples/ also illustrate how to use corrfitter; see
examples/README for more information.
Information on how to install the library is in the file INSTALLATION. To test the module try 'make tests'.
This module requires the lsqfit and gvar Python packages.
Background information on the some of the fitting strategies used by
corrfitter can be found by doing a web searches for "hep-lat/0110175",
"arXiv:1111.1363", and :arXiv:1406.2279" (appendix). These are papers by
G.P. Lepage and collaborators whose published versions are:
G.P. Lepage et al, Nucl.Phys.Proc.Suppl. 106 (2002) 12-20;
K. Hornbostel et al, Phys.Rev. D85 (2012) 031504; and
C.M. Bouchard et al, Phys.Rev. D90 (2014) 054506.
corrfitter version numbers have the form major.minor.patch where
incompatible changes are signaled by incrementing the major version
number, the minor number signals new features, and the patch number
signals bug fixes.
