Num Namelist Group

The &num namelist group controls numerical aspects of calculations. The input file can contain one or more, but only the last (tag-matching) one is used. The following options are available:

diff_scheme (type: string, default: 'COLLOC_GL2'`)

Difference equation scheme; one of

'COLLOC_GL2' : Second-order Gauss-Legendre collocation
'COLLOC_GL4' : Fourth-order Gauss-Legendre collocation
'COLLOC_GL6' : Sixth-order Gauss-Legendre collocation
'MAGNUS_GL2' : Second-order Gauss-Legendre Magnus
'MAGNUS_GL4' : Fourth-order Gauss-Legendre Magnus
'MAGNUS_GL6' : Sixth-order Gauss-Legendre Magnus
'MIRK' : Fourth-order mono-implicit Runge-Kutta (experimental)
'TRAPZ' : Trapezoidal, with the prescription by Sugimoto (1970) for non-adiabatic cases

real_root_solver (type: string, default: 'BRENT')

Root solver for real arithmetic; one of

'BRENT' : Brent’s method

cmplx_root_solver (type: string, default: 'RIDDERS')

Root solver for complex arithmetic; one of

'RIDDERS' : Complex Ridders’ method
'SECANT' : Secant method
'SIMPLEX' : Simplex method

n_iter_max (type: integer, default: 50): Maximum number of iterations in root-finding algorithms

ad_matrix_solver (type: string, default: 'ROWPP'`)

Matrix solver for discretized adiabatic equations; one of

'BANDED' : Banded factorization (LAPACK xGBTRF routines)
'CYCLIC' : Cyclic structured factorization (Wright 1994)
'ROWPP' : Gaussian elimination with row partial pivoting

nad_matrix_solver (type: string, default: 'CYCLIC'): Matrix solver for discretized non-adiabatic equations; same choices as for ad_matrix_solver

deflate_roots (type: logical, default: .TRUE.): Use deflation during complex root finding; this helps avoid the same eigenfrequency being found multiple times

restrict_roots (type: logical, default: .TRUE.): Discard roots that fall outside the bounds of the frequency scan

ad_search (type: string, default: 'BRACKET')

Initial search method for adiabatic calculations; one of

'BRACKET' : Bracket sign changes in the discriminant function

nad_search (type: string, default: 'AD')

Initial search method for non-adiabatic calculations; one of

'AD' : Use adiabatic eigenfrequencies
'MINMOD' : Find minima in the modulus of the discriminant function, along the real-\(\omega\) axis
'CONTOUR' : Find intersections between real and imaginary zero-contours of the discriminant function
'FILE' : Read frequencies from a file (see the file and file_format options)

See the Non-Adiabatic Oscillations chapter for further details about these search methods

file (type: string, default: ''): Name of file containing frequency data. Used only when nad_search = 'FILE'

file_format (type: string, default: '')

Format of file containing frequency data; one of

'TEXT': text file with one frequency per line
'SUMMARY': summary file with frequencies provided in omega dataset

Used only when nad_search = 'FILE'