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hydrogym.firedrake.utils.stability

stability_analysis​

def stability_analysis(flow,
                       sigma=0.0,
                       krylov_dim=100,
                       tol=1e-6,
                       adjoint=False,
                       schur_restart=False,
                       schur_delta=0.1,
                       n_evals=12)

Linear stability analysis of the flow.

Arguments:

  • flow - The FlowConfiguration to analyze. sigma: The shift for the shift-invert Arnoldi method. The algorithm will converge most quickly if the shift is close to the eigenvalues of interest.
  • m - The dimension of the Krylov subspace (number of Arnoldi vectors).
  • tol - Tolerance to use for determining converged eigenvalues.
  • adjoint - If True, compute the adjoint modes along with the direct modes. schur_restart: If True, use Krylov-Schur iteration to restart the Arnoldi process. schur_delta: The stability margin to use when determining which Schur eigenvalues to keep in Krylov-Schur iteration. Ignored if schur_restart is False. n_evals: The number of eigenvalues to converge in order to terminate Krylov-Schur iteration. Ignored if schur_restart is False.