Documentation

Examples

• Anderson impurity model (SIAM)
• Anderson-Holstein impurity model
• DMFT for Hubbard and Hubbard-like models

Model templates

• SIAM (QS)
• SIAM (QSZ)
• Holstein (QS)
• 2orb-UJ (QS)
• Generating new templates for custom models

Miscelaneous

• Install nrgljubljana_interface
• Parallelization
• Temporary files
• Reporting issues
• About nrgljubljana_interface

C++ reference manual

• nrgljubljana_interface
  • Type aliases
  • Classes

Python reference manual

class nrgljubljana_interface.Flat(half_bandwidth)

The Hilbert transform of a flat density of states, with cut-off

\[g(z) = \int \frac{A(\omega)}{z-\omega} d\omega\]

where \(A(\omega) = \theta( D^2 - \omega^2)/(2D)\).

(Only works in combination with frequency Green’s functions.)

class nrgljubljana_interface.SemiCircular(half_bandwidth, chem_potential=0.0)

Hilbert transform of a semicircular density of states, i.e.

\[g(z) = \int \frac{A(\omega)}{z-\omega} d\omega\]

where \(A(\omega) = \theta( D - |\omega|) 2 \sqrt{ D^2 - \omega^2}/(\pi D^2)\).

(Only works in combination with frequency Green’s functions.)

class nrgljubljana_interface.Solver(**params_kw)

solve(**params_kw)

Solve the impurity problem.

Parameters:

params_kw : dict {‘param’:value} that is passed to the core solver.

class nrgljubljana_interface.SolverCore

The Solver class

A_w

The spectral function

B_w

The spectral function of the auxiliary correlator F_w

Delta_w

The hybridization function in real frequencies

F_w

The auxiliary Green function F_w = Sigma_w * G_w

G_w

The retarded Greens function

Sigma_w

The retarded Self energy

check_model_params()

Signature : (nrgljubljana_interface::solve_params_t sp) -> None

chi_NN_w

Charge susceptibility

chi_SS_w

Spin susceptibility

chi_struct

The susceptibility structure object

create_tempdir()

Signature : (str tempdir_) -> str

expv

Expectation values of local impurity operators

generate_param_file()

Signature : (float z) -> None

gf_struct

The Green function structure object

static hdf5_format()

Signature : () -> str

instantiate()

Signature : (float z, str taskdir) -> None

log_mesh

Logarithmic mesh

nrg_params

Low-level NRG parameters

readA()

Signature : (str name, std::optional<g_w_t> A_w, triqs::hilbert_space::gf_struct_t _gf_struct) -> None Read a block spectral function name-block-ij.dat; here we assume that the

spectral function is purely real.

readGF()

Signature : (str name, std::optional<g_w_t> G_w, triqs::hilbert_space::gf_struct_t _gf_struct) -> None Read a block Green’s function (im/re)name-block-ij.dat

read_structure()

Signature : (str filename, bool mandatory) -> triqs::hilbert_space::gf_struct_t

readexpv()

Signature : (int Nz) -> None Read expectation values

set_nrg_params()

Parameter Name	Type	Default	Documentation
dmnrg	bool	false	Perform DMNRG (density-matrix NRG) calculation
cfs	bool	false	Perform CFS (complete Fock space) calculation
fdm	bool	true	Perform FDM (full-density-matrix) calculation
fdmexpv	bool	true	Calculate expectation values using FDM algorithm
dmnrgmats	bool	false	DMNRG calculation on Matsubara axis
fdmmats	bool	false	FDM calculation on Matsubara axis
mats	size_t	100	Number of Matsubara points to collect
specgt	std::string	“”	Conductance curves to compute
speci1t	std::string	“”	I_1 curves to compute
speci2t	std::string	“”	I_2 curves to compute
v3mm	bool	false	Compute 3-leg vertex on matsubara/matsubara axis?
mMAX	int	-1	Number of sites in the star representation
Nmax	int	-1	Number of sites in the Wilson chain
xmax	double	-1.0	Largest x in the discretization ODE solver
discretization	std::string	“Z”	Discretization scheme
z	double	1.0	Parameter z in the logarithmic discretization
tri	std::string	“old”	Tridiagonalisation approach
preccpp	size_t	2000	Precision for tridiagonalisation
diag	std::string	“default”	Eigensolver routine (dsyev|dsyevr|zheev|zheevr|default)
diagratio	double	1.0	Ratio of eigenstates computed in partial diagonalisation
dsyevrlimit	size_t	100	Minimal matrix size for dsyevr
zheevrlimit	size_t	100	Minimal matrix size for zheevr
restart	bool	true	Restart calculation to achieve truncation goal?
restartfactor	double	2.0	Rescale factor for restart=true
safeguard	double	1e-5	Additional states to keep in case of a near degeneracy
safeguardmax	size_t	200	Maximal number of additional states
fixeps	double	1e-15	Threshold value for eigenvalue splitting corrections
betabar	double	1.0	Parameter bar{beta} for thermodynamics
gtp	double	0.7	Parameter p for G(T) calculations
chitp	double	1.0	Parameter p for chi(T) calculations
finite	bool	false	Perform Costi-Hewson-Zlatic finite-T calculation
cfsgt	bool	false	CFS greater correlation function
cfsls	bool	false	CFS lesser correlation function
fdmgt	bool	false	FDM greater correlation function?
fdmls	bool	false	FDM lesser correlation function?
fdmexpvn	size_t	0	Iteration where we evaluate the expectation values
finitemats	bool	false	T>0 calculation on Matsubara axis
dm	bool	false	Compute density matrixes?
broaden_min_ratio	double	3.0	Auto-tune broaden_min parameter
omega0	double	-1.0	Smallest energy scale in the problem
omega0_ratio	double	1.0	omega0 = omega0_ratio x T
diagth	int	1	Number of diagonalisation threads
substeps	bool	false	Interleaved diagonalization scheme
strategy	std::string	“kept”	Recalculation strategy
Ninit	size_t	0	Initial Wilson chain ops
reim	bool	false	Output imaginary parts of correlators?
dumpannotated	size_t	0	Number of eigenvalues to dump
dumpabs	bool	false	Dump in terms of absolute energies
dumpscaled	bool	true	Dump using omega_N energy units
dumpprecision	size_t	8	Dump with # digits of precision
dumpgroups	bool	true	Dump by grouping degenerate states
grouptol	double	1e-6	Energy tolerance for considering two states as degenerate
dumpdiagonal	size_t	0	Dump diagonal matrix elements
savebins	bool	true	Save binned (unbroadened) data
broaden	bool	false	Enable broadening of spectra
emin	double	-1.0	Lower binning limit
emax	double	-1.0	Upper binning limit
bins	size_t	1000	bins/decade for spectral data
accumulation	double	0.0	Shift of the accumulation points for binning
linstep	double	0	Bin width for linear mesh
discard_trim	double	1e-16	Peak clipping at the end of the run
discard_immediately	double	1e-16	Peak clipping on the fly
goodE	double	2.0	Energy window parameter for patching
NN1	bool	false	Do N/N+1 patching?
NN2even	bool	true	Use even iterations in N/N+2 patching
NN2avg	bool	false	Average over even and odd N/N+2 spectra
NNtanh	double	0.0	a in tanh[a(x-0.5)] window function
width_td	size_t	16	Width of columns in ‘td’ output file
width_custom	size_t	16	Width of columns in ‘custom’ output file
prec_td	size_t	10	Precision of columns in ‘td’ output file
prec_custom	size_t	10	Precision of columns in ‘custom’ output file
prec_xy	size_t	10	Precision of spectral function output
resume	bool	false	Attempt restart?
log	std::string	“”	List of tokens to define what to log
logall	bool	false	Log everything
done	bool	true	Create DONE file?
calc0	bool	true	Perform calculations at 0-th iteration?
lastall	bool	false	Keep all states in the last iteratio for DMNRG
lastalloverride	bool	false	Override automatic lastall setting
dumpsubspaces	bool	false	Save detailed subspace info
dump_f	bool	false	Dump <f> matrix elements
dumpenergies	bool	false	Dump (all) energies to file?
logenumber	size_t	10	# of eigenvalues to show for log=e
stopafter	std::string	“”	Stop calculation at some point?
forcestop	int	-1	Stop iteration?
removefiles	bool	true	Remove temporary data files?
noimag	bool	true	Do not output imaginary parts of expvs
checksumrules	bool	false	Check operator sumrules
checkdiag	bool	false	Test diag results
checkrho	bool	false	Test tr(rho)=1

set_verbosity()

Signature : (bool v) -> None

solve()

Solve method that performs NRGLJUBLJANA_INTERFACE calculation

Parameter Name	Type	Default	Documentation
Lambda	double	2.0	Logarithmic discretization parameter
Nz	int	1	Number of discretization meshes
Tmin	double	1e-4	Lowest scale on the Wilson chain
keep	size_t	100	Maximum number of states to keep at each step
keepenergy	double	-1.0	Cut-off energy for truncation
keepmin	size_t	0	Minimum number of states to keep at each step
T	double	0.001	Temperature, k_B T/D,
alpha	double	0.3	Width of logarithmic gaussian
gamma	double	0.2	Parameter for Gaussian convolution step
method	std::string	“fdm”	Method for calculating the dynamical quantities
bandrescale	double	-1.0	Band rescaling factor (half-width of the support of the hybridisation function)
model_parameters	std::map<std::string, double>	–	Model parameters

solve_one()

Signature : (str taskdir) -> None

tdfdm

Thermodynamic variables (FDM algorithm)