ITERATIVE_SOLVER

iterative_solver section [Edit on GitHub]

Keywords

• CONVERGE_BY_ENERGY

• EARLY_RESTART

• EMPTY_STATES_TOLERANCE

• ENERGY_TOLERANCE

• EXTRA_ORTHO

• INIT_EVAL_OLD

• INIT_SUBSPACE

• LOCKING

• MIN_NUM_RES

• MIN_OCCUPANCY

• MIN_TOLERANCE

• NUM_SINGULAR

• NUM_STEPS

• RELATIVE_TOLERANCE

• RESIDUAL_TOLERANCE

• SUBSPACE_SIZE

• TOLERANCE_RATIO

• TOLERANCE_SCALE

• TYPE

Keyword descriptions

CONVERGE_BY_ENERGY

Type: integer
Default: 1

Description: Defines the flavour of the iterative solver.

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EARLY_RESTART

Type: real
Default: 5.00000000E-001

Description: Restart early when the ratio unconverged vs lockable vectors drops below this threshold.

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EMPTY_STATES_TOLERANCE

Type: real
Default: 0.00000000E+000

Description: Additional tolerance for empty states.

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ENERGY_TOLERANCE

Type: real
Default: 1.00000000E-002

Description: Tolerance for the eigen-energy difference \f\( |\epsilon_i^{old} - \epsilon_i^{new} | \f\)

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EXTRA_ORTHO

Type: logical
Default: F
Lone keyword: T

Description: Orthogonalize the new subspace basis functions one more time in order to improve the numerical stability.

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INIT_EVAL_OLD

Type: logical
Default: T
Lone keyword: T

Description: Initialize eigen-values with previous (old) values.

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INIT_SUBSPACE

Type: enum
Default: LCAO

Description: Tell how to initialize the subspace.

Valid values:

• LCAO

• RANDOM

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LOCKING

Type: logical
Default: T
Lone keyword: T

Description: Lock eigenvectors of the smallest eigenvalues when they have converged at restart.

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MIN_NUM_RES

Type: integer
Default: 0

Description: Minimum number of residuals to continue iterative diagonalization process.

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MIN_OCCUPANCY

Type: real
Default: 1.00000000E-014

Description: Minimum occupancy below which the band is treated as being ‘empty’

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MIN_TOLERANCE

Type: real
Default: 1.00000000E-013

Description: Minimum tolerance of the iterative solver.

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NUM_SINGULAR

Type: integer
Default: -1

Description: Number of singular components for the LAPW Davidson solver.

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NUM_STEPS

Type: integer
Default: 20

Description: Number of steps (iterations) of the solver.

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RELATIVE_TOLERANCE

Type: real
Default: 0.00000000E+000

Description: Relative tolerance for the residual L2 norm. (0 means this criterion is effectively not used.

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RESIDUAL_TOLERANCE

Type: real
Default: 1.00000000E-006

Description: Tolerance for the residual L2 norm.

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SUBSPACE_SIZE

Type: integer
Default: 2

Description: Size of the variational subspace is this number times the number of bands.

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TOLERANCE_RATIO

Type: real
Default: 0.00000000E+000

Description: Fine control of the empty states tolerance.

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TOLERANCE_SCALE

Type: real[2]
Default: 1.00000000E-001 5.00000000E-001

Description: Scaling parameters of the iterative solver tolerance.

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TYPE

Type: enum
Default: AUTO

Description: Type of the iterative solver.

Valid values:

• AUTO

• EXACT

• DAVIDSON

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