# setEigSolver¶

GraphISO.setEigSolver(**kwargs)

Set some or all of the eigenvalue solver properties.

Keyword Arguments:

• esolver (str) – the eigensolver algorithm to use.
• 'krylovschur' (default) - Krylov-Schur
• 'arnoldi' - Arnoldi Method
• 'lanczos' - Lanczos Method
• 'power' - Power Iteration/Rayleigh Quotient Iteration
• 'gd' - Generalized Davidson
• 'jd' - Jacobi-Davidson,
• 'lapack' - Uses LAPACK eigenvalue solver routines
• 'arpack' - only available if SLEPc is compiled with ARPACK linking
• workType (str) – can be used to set the eigensolver worktype (either 'ncv' or 'mpd'). The default is to let SLEPc decide.
• workSize (int) – sets the work size if workType is set.
• tolIn (float) – tolerance of the eigenvalue solver (default 0. (SLEPc decides)).
• maxIt (int) – maximum number of iterations of the eigenvalue solver (default 0 (SLEPc decides)).
• verbose (bool) – if True, writes eigensolver information to the console
• emax_estimate (float) – used to override the calculation of the graphs maximum eigenvalue.

Caution

• If supplied, the value of emax_estimate$$\hat{\lambda}_{\max}$$ must satisfy $$\hat{\lambda}_{\max}\geq\lambda_{\max}$$, where $$\lambda_{\max}$$ is the actual maximum eigenvalue of the graph.
• The greater the value of $$\hat{\lambda}_{\max} -\lambda_{\max}$$, the longer the convergence time of the chebyshev propagator.

Note

• These properties only apply if propagator='chebyshev'
• For more information regarding these properties,refer to the SLEPc documentation