expand_to_left()

void syten::MPS::expand_to_left	(	Tensor< 3 > const &	right,
		Tensor< 3 > const &	source,
		Tensor< 4 > const &	op,
		State &	target,
		Index const	position,
		SRDef const	alpha = 0.1,
		Index const	max_blocksize = 15,
		SRDef const	ratio = 1.,
		Index const	min_blocksize = 1
	)

Calculates an expansion term according to DMRG3S pointing to the left.

Parameters

right	the right-contraction to the right of the active site
source	the local mps component
op	the local mpo component
target	the target MPS state
position	the position in the target state, sites position and position-1 will be affected.
alpha	the mixing factor.
max_blocksize	maximal blocksize of the expander
ratio	the ratio of kept to discarded states
min_blocksize	minimal blocksize of the expander

References syten::MPS::Operator::dIdx, syten::MPS::State::dropUnmatched(), syten::expansion(), syten::genFuse(), syten::MPS::Operator::lIdx, syten::MPS::State::lIdx, norm(), syten::overThreshold(), syten::MPS::Operator::rIdx, syten::MPS::State::rIdx, SYTEN_ZNORM_THRESHOLD, syten::MPS::Operator::uIdx, syten::MPS::State::uIdx, syten::underThreshold(), and syten::zeroExpand().

Referenced by apply_op_orthogonalise_fit(), syten::MPS::DMRG::Worker::sweepLeft(), and syten::MPS::DMRG::Worker::sync().

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