INTERACTIVE

INTERACTIVE = [logical]
Default: INTERACTIVE = .FALSE. 

Description: Select the use of interactive mode.

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INTERACTIVE = .TRUE. enables the interactive mode. The interactive mode is executed by inputting a series of structures into the VASP executable, i.e.:

vasp_std < POSCAR.interactive

The number of ionic steps NSW should be set to the number of structures in the POSCAR.interactive file; the number of atoms in these input structures must be constant. Bear in mind that POSCAR.interactive is just a dummy name for a file that pipes the structures to the executable.

Important: The corresponding POSCAR file is required. The first set of positions comes from it, and the calculation will not run without it. After the POSCAR structure, the POSCAR.interactive structures will be read.

Fixed lattice (ISIF < 3)

For a fixed lattice ISIF < 3, the lattice is defined by the POSCAR file. The input structure in fractional/ direct coordinates (e.g., POSCAR.interactive, or any other name) is as follows:

  0.51602654  0.60200207  0.48355839
  0.47803882  0.52340268  0.50869036
  0.56717477  0.65578242  0.53100206
  0.45116332  0.63676166  0.43537938
  0.31530340  0.74388198  0.64715720
  0.60071504  0.49851047  0.37872126

  0.44216661  0.56361173  0.52960446
  0.36537533  0.54238027  0.56342416
  0.50398907  0.58877046  0.59064245
  0.43618126  0.61788131  0.46024981
  0.45532341  0.84599587  0.53226938
  0.50724841  0.41695239  0.46229896

  0.53802286  0.56353392  0.51036499
  0.47205503  0.63101620  0.50503092
  0.55908887  0.54004979  0.59586980
  0.61484211  0.57816646  0.45750405
  0.42364771  0.83966876  0.53596644
  0.46803897  0.42328326  0.47142822

with the coordinates of the ions for each structure given, followed by a blank line, then the next structure, etc. These calculations will then be performed on these structures. As each file is read in, the following will be printed to the stdout:

POSITIONS: reading from stdin

POSITIONS: read from stdin

Variable lattice (ISIF ≥ 3)

When the lattice is not fixed ISIF ≥ 3, the input structure (direct or Cartesian) requires that the lattice also be defined, i.e., POSCAR.interactive is a list of POSCAR files (i.e., the same format as an XDATCAR file):

unknown system
           1
    -5.608199   -5.441585   -0.050512
    -5.462972   -0.042950   -5.505922
     0.000000   -5.460525   -5.460525
   Si
    16
Direct configuration=          29
   0.16107731  0.07535964  0.14569368
   0.08094105  0.11968075  0.63676797
   0.12674262  0.62205394  0.16549329
   ...
   0.76282682  0.79675752  0.20047467
   0.72878930  0.77068250  0.75446889
unknown system
           1
    -5.614679   -5.440682   -0.050669
    -5.464721   -0.042862   -5.507583
     0.000000   -5.461359   -5.461359
   Si
    16
Direct configuration=          30
   0.16122201  0.07550654  0.14846295
   0.08038750  0.12050178  0.63429276
   0.12832567  0.62549860  0.16421982
   ...
   0.76048160  0.79907085  0.19846135
   0.73319285  0.76646271  0.75715487

As each structure is read in, the following will be printed to stdout:

POSITIONS AND LATTICE: reading from stdin

POSITIONS AND LATTICE: read from stdin

Important: Although the lattice changes, the plane wave basis remains the same. Be sure that your basis is sufficiently converged to avoid Pulay stress.

Tip: We suggest using it to systematically improve machine-learned force fields (MLFF) by selecting the structures for which the MLFF has broken down and continuing to train the MLFF with them. These structures are those where the spilling factor (cf. ML_ESTBLOCK) strongly deviates from 0, approaching 1.

Related tags and articles

Tags: IBRION, ISIF, NSW

Files: POSCAR, XDATCAR

How-to: Using metadynamics to train a machine-learned force field

Workflows that use this tag