krypy.recycling.factories - deflation vector factories

class krypy.recycling.factories.RitzFactory(subset_evaluator, subsets_generator=None, mode='ritz', print_results=None)

Bases: krypy.recycling.factories._DeflationVectorFactory

Factory of Ritz vectors for automatic recycling.

  • subset_evaluator – an instance of _RitzSubsetEvaluator that evaluates a proposed subset of Ritz vectors for deflation.
  • subsets_generator – (optional) an instance of _RitzSubsetsGenerator that generates lists of subsets of Ritz vectors for deflation.
  • print_results

    (optional) may be one of the following:

    • None: nothing is printed.
    • ‘number’: the number of selected deflation vectors is printed.
    • ‘values’: the Ritz values corresponding to the selected Ritz vectors are printed.
    • ‘timings’: the timings of all evaluated subsets of Ritz vectors are printed.
class krypy.recycling.factories.RitzFactorySimple(mode='ritz', n_vectors=0, which='sm')

Bases: krypy.recycling.factories._DeflationVectorFactory

Selects a fixed number of Ritz or harmonic Ritz vectors with respect to a prescribed criterion.

  • mode – See mode parameter of Ritz.
  • n_vectors – number of vectors that are chosen. Actual number of deflation vectors may be lower if the number of Ritz pairs is less than n_vectors.
  • which

    the n_vectors Ritz vectors are chosen such that the corresponding Ritz values are the ones with

    • lm: largest magnitude.
    • sm: smallest magnitude.
    • lr: largest real part.
    • sr: smallest real part.
    • li: largest imaginary part.
    • si: smallest imaginary part.
    • smallest_res: smallest Ritz residual norms.
class krypy.recycling.factories.UnionFactory(factories)

Bases: krypy.recycling.factories._DeflationVectorFactory

Combine a list of factories.

Parameters:factories – a list of factories derived from _DeflationVectorFactory.
class krypy.recycling.factories._DeflationVectorFactory

Abstract base class for selectors.


Get deflation vectors.

Returns:numpy.array of shape (N,k)