Introduction

Interfaces

root/

root/utils

Data structures

Examples

Decimation

  Copyright (C) 2009-2015 Peter Rakyta, Ph.D.

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
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Description

Returns a function handle to reduce the number of sites in the Hamiltonian via decimation procedure.

Syntax

handle = Decimation(Opt, varargin)

Parameters

Opt

Stucture containing the computational parameters. The required fields of the structure are the following:

Decimation
set 1 or 2 for algorithm decimation_1_and_2, or set 3 for algorithm decimation_3
Decimation_block
An integer value standing for the largest block of sites to be decimated together. (Decimation=1 implies Decimation_block=1).
Silent
Set true to suppress the displaying of output messages.

See more details about the data structure here.

varargin

Optional parameters given by a sequence ...'name', value,... . Possible parameter names are the following:

ForcedDecimation
Set true to override the parameter Opt.Decimation to 3.

Attributes

ForcedDecimation
Set true to override Opt.Decimation = 3.
Opt
An instance of the structure Opt

Methods

decimation_3
decimation_1_and_2

Decimation::decimation_3

Description

Algorithm to reduce the number of the sites in the Hamiltonian via decimation. The number of the decimated sites in one turn varies dynamically in order to avoid badly conditioned matrices.

Syntax

handle(E, Way2Hamiltonian, NameOfH, NameOfKulso_szabfokok )

Parameters
E	The energy used in the calculations.
Way2Hamiltonian	An instance of interface CreateHamiltoninans.
NameOfH	String containing the name of the Hamiltonian to be accessed by the "Read()" function of "Way2Hamiltonian" (Typically used "Hscatter").
NameOfKulso_szabfokok	String containing the name of the list of sites to be kept after the deciamtion. The list is obtained by the "Read()" function of "Way2Hamiltonian". (Typically used "kulso_szabfokok").

Decimation::decimation_1_and_2

Description

Algorithm to reduce the number of sites in the Hamiltonian via decimation. The number of the decimated sites is fixed during the calculations.

Syntax

handle(E, Way2Hamiltonian, NameOfH, NameOfKulso_szabfokok )

Parameters
E	The energy
Way2Hamiltonian	An instance of interface CreateHamiltoninans.
NameOfH	String containing the name of the Hamiltonian to be accessed by the "Read()" function of "Way2Hamiltonian" (Typically used "Hscatter").
NameOfKulso_szabfokok	String containing the name of the list of sites to be kept after the deciamtion. The list is obtained by the "Read()" function of "Way2Hamiltonian". (Typically used "kulso_szabfokok").