Basis Set Specs

Description

A cluster expansion basis set is specified by two components, one specifying basis function type and order, and one specifying cluster orbits.

Project files

This format is used for the bspecs.json file.

JSON Attributes List

ClexBasisSpecs attributes:

Name	Description	Format
basis_function_specs	Basis function specifications	Basis Function Specs
cluster_specs	Cluster orbit specifications	Cluster Specs

JSON Attributes Description

• basis_function_specs: Basis Function Specs (required)

  Specifies the type and order of basis functions. See the Basis Function Specs JSON input format.

• cluster_specs: Cluster Specs (required)

  Specifies the cluster orbits on which basis functions are generated. See the Cluster Specs JSON input format.

Examples

Example 1) Periodic cluster expansion

{
  "basis_function_specs" : {
    "global_max_poly_order": 3,
    "dof_specs": {
      "occ": {
        "site_basis_functions" : "occupation"
      }
    }
  },
  "cluster_specs": {
    "method": "periodic_max_length",
    "params": {
      "orbit_branch_specs": {
        "2" : {"max_length" : 6.},
	      "3" : {"max_length" : 3.}
      }
    }
  }
}

Example 2) Local cluster expansion

{
  "basis_function_specs" : {
    "dof_specs": {
      "occ": {
        "site_basis_functions" : "occupation"
      }
    }
  },
  "cluster_specs": {
    "method": "local_max_length",
    "params": {
      "phenomenal": {
        "coordinate_mode": "Integral",
        "sites": [
          [ 1, 0, 0, 0 ],
          [ 0, 1, 0, 0 ]
        ]
      },
      "generating_group": [ 0, 7, 11, 17, 18, 19, 26, 27, 28, 33, 37, 47 ],
      "orbit_branch_specs": {
        "1" : {"cutoff_radius": 6.},
        "2" : {"cutoff_radius": 3., "max_length" : 3.}
      }
    }
  }
}