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.

Parameters:

• 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.

get(deflated_solver)

Get deflation vectors.

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

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.

Parameters:

• 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.

get(solver)

Get deflation vectors.

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

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.

get(solver)

Get deflation vectors.

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

class krypy.recycling.factories._DeflationVectorFactory

Abstract base class for selectors.

get(solver)

Get deflation vectors.

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