PEXSI
Specifies the parameters of the PEXSI library. The density matrix is calculated with PEXSI if PURIFICATION_METHOD (in LS_SCF section) is set to PEXSI. The computational cost of PEXSI is at most quadratically scaling w.r.t. the system size and PEXSI is applicable to insulating and metallic systems. The value of EPS_PGF_ORB (in QS input section) defines the sparsity of the matrices sent to PEXSI and EPS_FILTER is overwritten with 0. [Edit on GitHub]
Keywords
Keyword descriptions
- CSR_SCREENING
Type: logical
Default: T
Lone keyword: TDescription: Whether distance screening should be applied to improve sparsity of CSR matrices.
- GAP
Type: real
Default: 0.00000000E+000 [hartree]Description: Spectral gap. Note: This can be set to be 0 in most cases.
- IS_INERTIA_COUNT
Type: logical
Default: F
Lone keyword: TDescription: Whether inertia counting is used each time the DFT driver of PEXSI is invoked. If FALSE, inertia counting is still used in the first SCF iteration.
- MAX_PEXSI_ITER
Type: integer
Default: 5Description: Maximum number of PEXSI iterations after each inertia counting procedure.
- MIN_RANKS_PER_POLE
Type: integer
Default: 64Description: The minimum number of processors used for each pole. The real number of processors per pole is the smallest number greater or equal to MIN_RANKS_PER_POLE that divides MPI size without remainder. For efficiency, MIN_RANKS_PER_POLE should be a small numbers (limited by the available memory).
- MU_INERTIA_EXPANSION
Type: real
Default: 1.50000000E-001 [hartree]Description: If the chemical potential is not in the initial interval, the interval is expanded by MU_INERTIA_EXPANSION.
- MU_INERTIA_TOLERANCE
Type: real
Default: 1.00000000E-002 [hartree]Description: Stopping criterion in terms of the chemical potential for the inertia counting procedure.
- MU_MAX_0
Type: real
Default: 5.00000000E+000 [hartree]Description: Initial guess of upper bound for mu.
- MU_MIN_0
Type: real
Default: -5.00000000E+000 [hartree]Description: Initial guess of lower bound for mu.
- MU_PEXSI_SAFE_GUARD
Type: real
Default: 1.00000000E-002 [hartree]Description: Safe guard criterion in terms of the chemical potential to reinvoke the inertia counting procedure.
- NP_SYMB_FACT
Type: integer
Default: 1Description: Number of processors for PARMETIS/PT-SCOTCH. Only used if ORDERING is set to PARALLEL. If 0, the number of processors for PARMETIS/PT-SCOTCH will be set equal to the number of MPI ranks per pole. Note: if more than one processor is used, a segmentation fault may occur in the symbolic factorization phase.
- NUM_ELECTRON_INITIAL_TOLERANCE
Type: real
Default: 0.00000000E+000Description: The same as NUM_ELECTRON_PEXSI_TOLERANCE but applied in the first SCF steps. If set to a value smaller than NUM_ELECTRON_PEXSI_TOLERANCE, it is overwritten with NUM_ELECTRON_PEXSI_TOLERANCE (default). If set to a value larger than NUM_ELECTRON_PEXSI_TOLERANCE, the PEXSI tolerance in number of electrons is set adaptively according to the SCF convergence error of the previous SCF step. This reduces the number of PEXSI iterations in the first SCF steps but leads to at least one more SCF step.
- NUM_ELECTRON_PEXSI_TOLERANCE
Type: real
Default: 1.00000000E-001Description: Stopping criterion of the PEXSI iteration in terms of The number of electrons compared to the exact number of electrons. This threshold is the target tolerance applied at convergence of SCF.
- NUM_POLE
Type: integer
Default: 64Description: Number of terms in the pole expansion (should be even).
- ORDERING
Type: enum
Default: PARALLELDescription: Ordering strategy for factorization and selected inversion.
Valid values:
PARALLELParallel ordering using ParMETIS/PT-SCOTCH (PARMETIS option in SuperLU_DIST)SEQUENTIALSequential ordering using METIS (METIS_AT_PLUS_A option in SuperLU_DIST)MULTIPLE_MINIMUM_DEGREEMultiple minimum degree ordering (MMD_AT_PLUS_A option in SuperLU_DIST)
- ROW_ORDERING
Type: enum
Default: NOROWPERMDescription: row permutation strategy for factorization and selected inversion.
Valid values:
NOROWPERMNo row permutation (NOROWPERM option in SuperLU_DIST)LARGEDIAGMake diagonal entry larger than off diagonal (LargeDiag option in SuperLU_DIST)
- TEMPERATURE
Type: real
Default: 3.00000000E+002 [K]Description: Electronic temperature
- VERBOSITY
Type: enum
Default: BASICDescription: The level of output information.
Valid values:
SILENTBASICDETAILED