def get_tridiagonal(self, cutoff=None, residual=False, get_trafo=False):
"""
Main interface. Computes the tridiagonal elements of the matrix A and returns them
:param cutoff: How many diagonal elements for the resulting tridiagonal elements should be computed
If left unchanged the entire matrix is tridiagonalized
:param residual: If set True computes a residual. See utils.residual.orth_residual for details
:param get_trafo: If set True computes and returns the transformaion matrix
:return: diag (diagonal elements of the computed tridiagonal matrix), offdiag (offdiagonal elements
of the computed tridiagonal matrix), info dict with keys 'trafo' and 'res', which
contain the corresponding transformation matrix and residual of the computation respectively
"""
if cutoff is None:
cutoff = self.max_cutoff
else:
assert 0 < cutoff <= self.max_cutoff
info = dict()
info['trafo'] = None
info['res'] = None
if residual or get_trafo:
diag, offdiag, V = self._core_loop_with_trafo(cutoff)
if get_trafo:
info['trafo'] = V
if residual:
info['res'] = orth_residual(V)
else:
diag, offdiag = self._core_loop(cutoff)
return diag, offdiag, info
def get_tridiagonal(self, cutoff=None, residual=False, get_trafo=False):
if cutoff is None:
cutoff = self.max_cutoff
else:
assert 0 < cutoff <= self.max_cutoff
info = dict()
info['trafo'] = None
info['res'] = None
if residual or get_trafo:
diag, offdiag, V = self._core_loop_with_trafo(cutoff)
if get_trafo:
info['trafo'] = V
if residual:
info['res'] = orth_residual(V)
else:
diag, offdiag = self._core_loop(cutoff)
return diag, offdiag, info
def get_tridiagonal(self,
cutoff=None,
residual=False,
get_trafo=False,
positive=True):
"""
Main interface. Computes the tridiagonal elements of the matrix A and returns them
:param cutoff: How many diagonal elements for the resulting tridiagonal elements should be computed
If left unchanged the entire matrix is tridiagonalized
:param residual: If set True computes a residual. See utils.residual.orth_residual for details
:param get_trafo: If set True computes and returns the transformaion matrix
:param positive: If set True ensures that the offdiagonal elements are chosen to be positive
:return: diag (diagonal elements of the computed tridiagonal matrix), offdiag (offdiagonal elements
of the computed tridiagonal matrix), info dict with keys 'trafo' and 'res', which
contain the corresponding transformation matrix and residual of the computation respectively
"""
if cutoff is None:
cutoff = self.n
else:
assert 0 < cutoff <= self.n
info = dict()
info['trafo'] = None
info['res'] = None
if residual or get_trafo:
diag, offdiag, Q = self._construct_hessenberg_with_trafo(cutoff)
if positive and get_trafo:
diag, offdiag, Q = self._make_positive(diag, offdiag, trafo=Q)
else:
diag, offdiag = self._make_positive(diag, offdiag)
if get_trafo:
info['trafo'] = Q
if residual:
info['res'] = orth_residual(Q)
else:
diag, offdiag = self._construct_hessenberg(cutoff)
if positive:
diag, offdiag = self._make_positive(diag, offdiag)
return diag, offdiag, info