kouzatsu configuration explained

cthyb.cfg is the main configuration file for kouzatsu CT-QMC hybridization expansion solver. I use boost's program_options library to read configuration files which is why that library (and only) is required to be present in compiled version for solver compilation.

For the moment configuration consists of three configuration groups: configuration, utility and files; and you don't want to move options between them (as many options have sensible default value and not required to be present in configuration file all the time).

Calculation
thermalization_sweeps=1000

Number of sweeps (by sweep we mean bin which contains several measurements, see below, but averaged to a single value) to be done for thermalization (no measurements will be done during thermalization sweeps) on each process.

total_sweeps=100000

Total sweeps to be done after thermalization on all processes cumulatively.

maximum_order=50

Limits observable perturbation order, have no effect on calculation whatsoever.

num_nn=100

Resolution of tau-mesh for nn-correlator calculation. Even if you measure only n0n0-correlator(single tau=0 point) whole tau-mesh is measured beforehand.

measurements_bin=2000

How many measurements we do (and then average) that represent single sweep.

num_shift=0

How many segment tail shifts to do each measurement. Kind of slow and wasn't tested extensively.

num_spinswap=20

Represents how frequently we do spinswaps.

minimum_occupation=7

Minimal size of configurations for atomic weights measurements.

num_matsubara=478

Number of frequencies for G(w) calculations. Also see energy cutoff below.

num_matsubara2=10

num_bosonic=2

Number of frequencies for two-particle green function measurements. Measurements in omega space are slow and number of measurements is flavors^2 * matsubara2^2 * bosonic (can be really big).

num_legendre=15

Number of legendre coefficients to measure (lmax in TRIQS paper). High value can produce some nasty noise (and therefore insensible Green functions). Its recommended to do big enough amount of measurements to cover as much polynomial coefficients as possible.

36 or so is generically safe value, however solver does some tests after calculation to check if too much or too little coefficients were measured.

num_slices=100

Number of tau-slices in input delta file. Be aware that number of points is slices+1.

num_tau_legendre_slices=1000

Number of tau-slices in G(t) transformed from G(l). Theoretically we can have as much points as we want.

num_flavors=10

Number of flavors in a system.

beta=1.0

For the moment always use 1.0

temp=10.0

Inverse temperature (beta).

use_energy_cutoff=300

If energy cutoff value is nonzero then number of matsubara frequencies is calculated from it.

swap_mode=1

Swap mode used in calculations:

0 - don't do any swaps

1 - swap all spin at once (ex. 1-6, 2-7 etc.)

2 - choose random orbital and swap its orbital if move passes energy check.

measure_green_omega=false
Measure Green function on matsubara frequencies.

measure_sigmag_omega=false

Measure SigmaG on matsubara frequencies. measure_green_omega is required.

measure_green_legendre=false

Measure Green function legendre coefficients.

measure_sigmag_legendre=false

Measure SigmaG legendre coefficients. measure_green_legendre is required.

measure_green2_omega=false

Measure two-particle Green function on matsubara frequencies.

measure_h_omega=false

measure_nnt=false

Deprecated.

measure_nnt_full=false

Measure n0nt-correlator.

measure_nn=true

Measure n0n0-correlator.

measure_atomic_weights=false

Measure atomic weights.

legendre_add_0_beta_points=false

Don't touch.

Utilty

maximum_time=17000

Maximum time in seconds to run calculation. After that all measurements are gathered and output files are produced from them.

notification_step=0.01

How frequently to report progress (0.01 - each 1%).

save_each_sweep=0
probabilities_each_sweep=0
occupations_each_sweep=0

Deprecated.

verbosity=10

Output verbosity. Zero for none.

jk_green_tau_from_legendre=false

Determines whether we use transformed G(l)->G(t) for JK-output file or not. Allows to use legenre measured green functions with JK DMFT code.

Files

umatrix=u_pd

File containing U-matrix.

delta=delta.tau

File containing delta function.

chempot=ene.tmp

File containing chempotentials.

jk_output=fort.10

Name of output file for JK DMFT code.