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Nonlinear solver for consistent initialization

Group /input/model/unit_XXX/discretization/consistency_solver - Nonlinear consistency solver parameters

The following specifications of the nonlinear solver for consistent initialization are available. The default is a COMPOSITE solver that applies multiple solvers subsequently, where the default is ATRN_ERR followed by LEVMAR.

SOLVER_NAME

Name of the solver. Available solvers are

  • LEVMAR: Levenberg-Marquardt method (ported from the MATLAB implementation)

  • ATRN_RES: Adaptive trust-region Newton solver, implementation of the NLEQ-RES algorithm described in [41] (p. 131)

  • ATRN_ERR: Robust adaptive trust-region Newton solver, implementation of the NLEQ-ERR algorithm described in [41] (pp. 148)

  • PTC: Pseudo-transient continuation method, see [41] (section 6.4)

  • COMPOSITE: Applies multiple solvers subsequently

    Type: string

    Length: \(1\)

SUBSOLVERS

Vector with names of solvers for the COMPOSITE solver (only required for composite solver). See SOLVER_NAME for available solvers.

Type: string

Length: \(\gt 1\)

INIT_DAMPING

Initial damping factor (default is \(0.01\)), only required for LEVMAR, ATRN_RES and ATRN_ERR. See SOLVER_NAME for available solvers.

Type: double

Range: \(\ge 0\)

Length: \(1\)

MIN_DAMPING

Minimal damping factor (default is \(0.0001\)), only required for ATRN_RES and ATRN_ERR. See SOLVER_NAME for available solvers.

Type: double

Range: \(\ge 0\)

Length: \(1\)

MAX_ITERATIONS

Maximum number of iterations (optional, defaults to \(50\) for LEVMAR, ATRN_RES and ATRN_ERR, and to \(100\) for PTC).

Type: int

Range: \(\ge 1\)

Length: \(1\)

INIT_PSEUDOTIMESTEP

Initial pseudo time step (optional, defaults to \(20.0\)), only used by PTC.

Type: double

Range: \(> 0\)

Length: \(1\)

MAX_NONMONOTONE_ITERATIONS

Maximum number of consecutive iterations in which the residual is allowed to grow (optional, defaults to \(5\)), only used by PTC.

Type: int

Range: \(\ge 0\)

Length: \(1\)

NUMERIC_VARIANT

Selects the numeric variant of the method (optional, defaults to \(0\)), only used by PTC.

Type: int

Range: \(\{0,1\}\)

Length: \(1\)