5. Input files

1. Parameter file (param.in)

• The format of the parameter file is the “name = value” pair format.

• # means a comment. In other words, a # character and the subsequent part in a line will be ignored.

• A blank line is skipped.

• The variables for which default value is not given are mandatory.

# character means comment

statistics = "fermion"  # stats.
beta = 100.0            # inv. temp.

### continued ###

• INPUT/OUTPUT

  Name	Type	Default value	Description
  statistics	String	—	Choose “fermion” or “boson”.
  beta	Double	—	The inverse temperature
  filein_G	String	Gtau.in	The name of an input file for Green’s function.
  column	Integer	1	The column number where the values of G(tau) are stored in the filein_G file.
  fileout_spec	String	spectrum.out	The name of output file of spectrum.
  fileout_pade	String	pade.out	The name of output file of spectrum calculated by the Pade approximant.

• OMEGA

  Name	Type	Default value	Description
  NOmega	Integer	1001	The number of omega to be calculated.
  omegamin	Double	-4	The minimum value of omega.
  omegamax	Double	4	The maximum value of omega.

  Note: The i-th omega where i=[0:Nomega) is given by .

• SVD

  Name	Type	Default value	Description
  SVmin	Double	1e-10	Truncation value of singular values.

• ADMM

  Name	Type	Default value	Description
  lambdalogmesh	Double	0.2	The log mesh of lambda.
  lambdalogbegin	Double	0	The log value of maximum lambda. lambda_max is given by .
  lambdalogend	Double	-1	The log value of minimum lambda. lambda_min is given by
  Nlambda	Integer	—	The number of lambda to be calculated.
  penalty	Double	10.0	The value of penalty coefficient. If negative, penalty is optimized during the iteration starting with its absolute value.
  tolerance	Double	1e-6	The criteria of convergence.
  maxiteration	Integer	1000	The maximum number of iterations.
  printlevel	Integer	2	0; minimum, 1; moderate, 2; verbose.

• SpM-Pade

  Name	Type	Default value	Description
  PadeEta	Double	0.0	The weight of the spectrum by the Pade approximant.
  filein_Gsigma	String	Gtau.in	The name of input file for errors of Green’s function.
  column_sigma	Integer	1	The column number where the errors of G(tau) are stored in the filein_Gsigma file.
  g_sigma	Double	inf	The errors of G(tau). If this is inf (default value), the errors will be loaded from a file specified by filein_Gsigma.
  NSamplePade	Integer	30	The number of random samples (with noise) will be used to calculate the expected value and the standard deviation of the spectrum by the Pade approximant.

2. Green’s function (Gtau.in)

   In SPM, the values of Green’s function is only used for calculation, i.e. tau is automatically determined by the beta and the step. Please indicate the column number where the values of G(tau) are stored by “column” in the parameter file.