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multibinit input variables

This document lists and provides the description of the name (keywords) of the multibinit input variables to be used in the input file for the multibinit executable.

bmass

Mnemonics: Barostat MASS
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: real
Dimensions: scalar
Default value: 10

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

See bmass

bound_SPCoupling

Mnemonics: BOUND Strain Phonon COUPLING coefficients
Mentioned in topic(s): topic_BoundingProcess
Variable type: integer
Dimensions: scalar
Default value: 1

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

Flag to activate the strain phonon coupling. When the bound process will generate the possible coefficients for the fit, if this input variable is set to 1, the generator will consider coefficients like (Sr-Ti)^2 eta^2

bound_anhaStrain

Mnemonics: BOUND ANHArmonic STRAIN coefficients
Mentioned in topic(s): topic_BoundingProcess
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

Flag to activate the anharmonic strain. When the bound process will generate the possible coefficients for the fit, if this input variable is set to 1, the generator will consider coefficients like eta^4

bound_cell

Mnemonics: BOUND superCELL size for the molecular dynamics
Mentioned in topic(s): topic_BoundingProcess
Variable type: integer
Dimensions: (3)
Default value: 6,6,6

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

When the process will try a given model, this input variable is used to set the size of the supercell for the molecular dynamics

bound_cutoff

Mnemonics: BOUND CUT OFF
Mentioned in topic(s): topic_BoundingProcess
Variable type: real
Dimensions: scalar
Default value: 1 unit cell

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

Cut-off for the anharmonic phonon interaction during the bound process (in Bohr)

bound_maxCoeff

Mnemonics: BOUND MAX COEFFicient
Mentioned in topic(s): topic_BoundingProcess
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

Number of maximum additional coefficients for the bound process

bound_model

Mnemonics: BOUND COEFFicient
Mentioned in topic(s): topic_BoundingProcess
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

Flag to activate the bound process:

  • 0 → Do not activate the bound process

  • 1 → This option will generate all the possible combinaisons of coefficients from 1 to bound_maxCoeff. Some constrains are imposed during the generation and the fit of the coefficients, they have to be positive and with even power. Finaly, the code will try all the possible combinaisons and try to find a bounded model.

  • 2 → new version This option will generate a set of coefficients with a power range defined by bound_rangePower and keep only the coefficients with even power. Then the procedure is similar to the fit process with the constrains to only keep positive coefficients. The bound process will select the coefficients one by one up to bound_maxCoeff and try if the model is bound at each step of the process.

Related variables: The number of maximum additional coefficient in the polynome (bound_maxCoeff), the power range for the additional coefficients (bound_rangePower), the cut off of the additional interactions (bound_cutoff)

bound_rangePower

Mnemonics: BOUND RANGE POWER
Mentioned in topic(s): topic_BoundingProcess
Variable type: integer
Dimensions: (2)
Default value: 6,6

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

Range of the power for the additional coefficients in the bound process

bound_step

Mnemonics: BOUND number of STEP for the molecular dynamics
Mentioned in topic(s): topic_BoundingProcess
Variable type: integer
Dimensions: scalar
Default value: 1000

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

When the process will try a given model, this input variable is used to set the maximum number of molecular dynamics steps

bound_temp

Mnemonics: BOUND TEMPerature for the molecular dynamics (in Kelvin)
Mentioned in topic(s): topic_BoundingProcess
Variable type: integer
Dimensions: scalar
Default value: 500

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

When the process will try a given model, this input variable is used to set the temperature for the molecular dynamics

coefficients

Mnemonics: values of the COEFFICIENTS
Mentioned in topic(s): topic_LatticeModel
Variable type: real
Dimensions: (ncoeff)
Default value: 0.0

Test list (click to open). Moderately used, [17/35] in all multibinit tests, [0/3] in multibinit tutorials

Set the values of the coefficients present in the XML file

dipdip

Mnemonics: DIPole-DIPole interaction
Mentioned in topic(s): topic_LatticeModel
Variable type: integer
Dimensions: scalar
Default value: 1

Test list (click to open). Very frequently used, [34/35] in all multibinit tests, [⅔] in multibinit tutorials
  • 0 → Do not recompute the dipole-dipole interaction.
  • 1 → Recompute the dipole-dipole interaction based on ewald summation .

dipdip_prt

Mnemonics: DIPole-DIPole PRinT
Mentioned in topic(s): topic_LatticeModel
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Very frequently used, [32/35] in all multibinit tests, [0/3] in multibinit tutorials
  • 1 → Print the dipole-dipole interaction into the XML.
  • 0 → Do not print the dipole-dipole interaction into the XML.

dipdip_range

Mnemonics: Dipole-Dipole interaction
Mentioned in topic(s): topic_LatticeModel
Variable type: integer
Dimensions: (3)
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

Depending of the cases, the range of the dipole-dipole interaction will be parameted by:

  • dipdip_range if superior to ncell and superior to short-range interaction
  • ncell if dipdip_range inferior to ncell
  • short-range if dipdip_range inferior to short-range interaction

For example:

* if dipdip_range = 2 2 2 and the short range interaction if 3 3 3, the dipdip interaction will be set on 3 3 3

* if ncell = 15 15 15 and the dipdip_range is 6 6 6, the dipdip interaction will be set on 15 15 15

dtion

Mnemonics: Delta Time for IONs
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: integer
Dimensions: scalar
Default value: 100

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

See dtion

dynamics

Mnemonics: Dynamics option for Multibinit
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Very frequently used, [22/35] in all multibinit tests, [⅓] in multibinit tutorials

Set the Dynamics option for Multibinit. This option is equivalent to ionmov:

  • 0 → do nothing

  • 12 → Isokinetic ensemble molecular dynamics. The equation of motion of the ions in contact with a thermostat are solved with the algorithm proposed by Zhang [J. Chem. Phys. 106, 6102 (1997)], as worked out by Minary et al [J. Chem. Phys. 188, 2510 (2003)]. The conservation of the kinetic energy is obtained within machine precision, at each step. Purpose: Molecular dynamics Cell optimization: No (Use optcell=0 only)

  • 13 → Isothermal/isenthalpic ensemble. The equation of motion of the ions in contact with a thermostat and a barostat are solved with the algorithm proposed by Martyna, Tuckermann Tobias and Klein [Mol. Phys., 1996, p. 1117]. If optcell=1 or 2, the mass of the barostat (bmass) must be given in addition. Purpose: Molecular dynamics Cell optimization: Yes (if optcell/=0) Related variables: The time step (dtion), the temperatures (mdtemp), the number of thermostats (nnos), and the masses of thermostats (qmass).

energy_reference

Mnemonics: Energy of the refences structure
Characteristics: ENERGY
Mentioned in topic(s): topic_LatticeModel
Variable type: real
Dimensions: scalar
Default value: 0.0

Test list (click to open). Moderately used, [10/35] in all multibinit tests, [0/3] in multibinit tutorials

Set the energy of the reference structure (from the DFT calculation) if the energy of the reference is not specified in the DDB, (for example if the DDB file of the ground states is not merged), or not specified in the XML file), (by default in Hartree).

fit_SPCoupling

Mnemonics: FIT anharmonic Strain-Phonon COUPLING coefficients
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: scalar
Default value: 1

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

Flag to activate the strain phonon coupling. This option will add coefficients like (Sr-Ti)^1 (eta^4)

fit_anhaStrain

Mnemonics: FIT ANHARmonic STRAIN coefficients
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

Flag to activate the anharmonic strain. This option will add coefficients like (eta^4)

fit_bancoeff

Mnemonics: FIT BANed COEFFicients
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: (fit_nbancoeff)
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

Indexes of the banned coefficients during the fit process of the model

fit_coeff

Mnemonics: FIT anharmonic COEFFficients
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Moderately used, [11/35] in all multibinit tests, [0/3] in multibinit tutorials

  • 0 → do not active the fit process

  • 1 → Activate the fit process. This option will first generate a set of coefficients if fit_generateCoeff is set to one. This generation is mainly parametrized by fit_rangePower and fit_cutoff. You can also provided a list of coefficients with the model_anharmonic.MXL (see multibinit help file). Then the fit process will select the coefficients one by one up to fit_ncoeff (see this paper for the details of the procedure).

  • -1 → only for developers, print the files for the scripts

fit_cutoff

Mnemonics: FIT CUT-OFF of the anharmonic phonon interaction
Mentioned in topic(s): topic_FitProcess
Variable type: real
Dimensions: scalar
Default value: Unit cell

Test list (click to open). Moderately used, [9/35] in all multibinit tests, [0/3] in multibinit tutorials

Cut-off for the anharmonic phonon interaction (in Bohr)

fit_fixcoeff

Mnemonics: FIT FIXed COEFFicients
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: (fit_nfixcoeff)
Default value: 0

Test list (click to open). Moderately used, [6/35] in all multibinit tests, [0/3] in multibinit tutorials

Indexes of the imposed coefficients during the fit process for the model:

fit_generateCoeff

Mnemonics: FIT GENERATE anharmonic COEFFicient
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: scalar
Default value: 1

Test list (click to open). Moderately used, [2/35] in all multibinit tests, [0/3] in multibinit tutorials

Flag to activate the generation of the anharmonic coefficient for the fit process

Related variables: The power range of the coefficients (fit_rangePower), the cut off of the interactions (fit_cutoff), the flag to add ahnarmonic strain (fit_anhaStrain), the flag to add phonon strain coupling (fit_SPCoupling)

fit_initializeData

Mnemonics: FIT INITIALIZE DATA for the fit
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

Flag to de/activate the precomputing and storage of all the data for the fit, it will reduce the computation time but increase a lot the memory…

fit_nbancoeff

Mnemonics: FIT Number of BANed COEFFicients
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

Number of imposed coefficients during the fit process of the model:

  • 0 → do not ban coefficients

  • n → ban n coefficients (requires fit_bancoeff input variable)

fit_ncoeff

Mnemonics: FIT Number of COEFFicients
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Moderately used, [11/35] in all multibinit tests, [0/3] in multibinit tutorials

Give the number of anharmonic coefficients to add in the model during the fit process

fit_nfixcoeff

Mnemonics: FIT Number of FIXed COEFFicients
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Moderately used, [7/35] in all multibinit tests, [0/3] in multibinit tutorials

Number of imposed coefficients during the fit process for the model:

  • -1 → fix all the coefficients

  • 0 → do not fix coefficients

  • n → fix n coefficients (requires fit_fixcoeff input variable)

fit_rangePower

Mnemonics: FIT RANGE POWER for the coefficients
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: (2)
Default value: 3 4

Test list (click to open). Moderately used, [5/35] in all multibinit tests, [0/3] in multibinit tutorials

Set the range of the powers for the anharmonic coefficients

fit_tolMSDE

Mnemonics: FIT TOLerance on Mean Standard Deviation of the Energy
Mentioned in topic(s): topic_FitProcess
Variable type: real
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

Tolerance of the fit based on the Mean Standard Deviation of the Energy in (meV/atm)

fit_tolMSDF

Mnemonics: FIT TOLerance on Mean Standard Deviation of the Forces
Mentioned in topic(s): topic_FitProcess
Variable type: real
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

Tolerance of the fit based on the Mean Standard Deviation of the Forces (eV2/A2)

fit_tolMSDFS

Mnemonics: FIT TOLerance on Mean Standard Deviation of the Forces and Stresses
Mentioned in topic(s): topic_FitProcess
Variable type: real
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

Tolerance of the fit based on the Mean Standard Deviation of the Forces and Sressses (eV2/A2)

fit_tolMSDS

Mnemonics: FIT TOLerance on Mean Standard Deviation of the Stresses
Mentioned in topic(s): topic_FitProcess
Variable type: real
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

Tolerance of the fit based on the Mean Standard Deviation of the Stresses in (eV2/A2)

ncell

Mnemonics: Number of Cell
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: integer
Dimensions: (3)
Default value: [6, 6, 6]

Test list (click to open). Very frequently used, [22/35] in all multibinit tests, [⅓] in multibinit tutorials

Give the size of the supercell for the dynamics

ncoeff

Mnemonics: Number of anharmonic COEFFicients
Mentioned in topic(s): topic_LatticeModel
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Moderately used, [17/35] in all multibinit tests, [0/3] in multibinit tutorials

Set the number of anharmonic coefficients in the model. This number have to be in agreement with the number of coefficients present in the XML file.

If ncoeff /= 0, coefficients have to be present in the input files

nctime

Mnemonics: NetCdf TIME between output of molecular dynamics informations
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: integer
Dimensions: scalar
Default value: 1

Test list (click to open). Moderately used, [1/35] in all multibinit tests, [0/3] in multibinit tutorials

Set the number of step between output the molecular dynamics informations in the NetCDF file

ngqpt

Mnemonics: Number of Grids points for Q PoinTs
Mentioned in topic(s): topic_LatticeModel
Variable type: integer
Dimensions: (3)
Default value: 3*1

Test list (click to open). Moderately used, [6/35] in all multibinit tests, [⅓] in multibinit tutorials

The Monkhorst-Pack grid linear dimensions, for the DDB (coarse grid).

nnos

Mnemonics: Number of NOSe masses
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

See nnos

nqshft

Mnemonics: Number of Q SHiFTs
Mentioned in topic(s): topic_LatticeModel
Variable type: integer
Dimensions: scalar
Default value: 1

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

The number of vector shifts of the simple Monkhorst and Pack grid, needed to generate the coarse grid of q points (for the series of fine grids, the number of shifts it is always taken to be 1). Usually, put it to 1. Use 2 if BCC sampling (Warning: not BCC lattice, BCC sampling), and 4 for FCC sampling (Warning: not FCC lattice, FCC sampling).

ntime

Mnemonics: Number of TIME step
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: integer
Dimensions: scalar
Default value: 200

Test list (click to open). Very frequently used, [22/35] in all multibinit tests, [⅓] in multibinit tutorials

Number of step for the dynamics

optcell

Mnemonics: OPTimize the CELL shape and dimensions
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Moderately used, [12/35] in all multibinit tests, [⅓] in multibinit tutorials

See optcell

prt_model

Mnemonics: Effective potential XML output
Mentioned in topic(s): topic_LatticeModel
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Very frequently used, [34/35] in all multibinit tests, [⅔] in multibinit tutorials
  • 0 → do nothing (Default).

  • 1 → Generate the XML file with:

     * The system definition and the model (Harmonic + Anharmonic) in _model.xml

  • 2 → Generate two XML files with:

     * The system definition and the model (Harmonic) in _sys.XML
 * The model (Anharmonic) in _coeffs.xml

  • 3 → Generate only one XML file with:

     * The system definition and the model (Harmonic) in _sys.XML

  • 4 → Generate only one XML file with:

     * The model (Anharmonic) in _coeffs.xml

    qmass

Mnemonics: Q thermostat MASS
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: real
Dimensions: (nnos)
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

See qmass

restartxf

Mnemonics: RESTART from (X,F) history
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

See restartxf

strtarget

Mnemonics: STRess TARGET
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: real
Dimensions: (6)
Default value: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

See strtarget

temperature

Mnemonics: molecular dynamics TEMPERATURE (in Kelvin)
Mentioned in topic(s): topic_DynamicsMultibinit
Variable type: real
Dimensions: scalar
Default value: 325

Test list (click to open). Very frequently used, [22/35] in all multibinit tests, [⅓] in multibinit tutorials

Give the temperature of the dynamics in Kelvin

ts_option

Mnemonics: FIT Training Set OPTION
Mentioned in topic(s): topic_FitProcess
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/35] in all multibinit tests, [0/3] in multibinit tutorials

  • 0 → the Training is hist from ABINIT

  • 1 → the Training contains -1 * stress (usualy output from VASP)