Numerical Parameters

The &num namelist group defines numerical method parameters; the input file can contain one or more, but only the last (matching) one is used. Allowable fields are:

diff_scheme (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' : Sourth-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
r_root_solver (default 'BRENT')

Root solver for real arithmetic; one of:

  • 'BRENT' : Brent’s method
c_root_solver (default 'RIDDERS')

Root solver for complex arithmetic; one of

  • 'RIDDERS' : Complex Ridders’ method
  • 'SECANT' : Secant method
  • 'SIMPLEX' : Simplex method
n_iter_max (default 50)
Maximum number of iterations in root-finding algorithm
matrix_type (default 'BLOCK’)

Storage type of system matrix; one of

  • 'BAND' : Band-structured
  • 'BLOCK' : Block-structued
deflate_roots (default .TRUE.)
Flag to use root deflation, which can avoid the same eigenfrequency being found multiple times
restrict_roots (default .TRUE.)
Flag to check each roots found lies within the bounds of the frequency scan
ad_search (default 'SCAN')

Initial search method for adiabatic calculations; one of

  • 'BRACKET' : Bracket sign changes in the discriminant function
nad_search (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
tag_list (default '', which matches all)
Comma-separated list of &mode tags to match