delinearise()

std::tuple< Index, STensor, STensor, SBasis > syten::STensorImpl::delinearise	(	STensor const &	in,
		SBasisId const &	uncombined,
		std::vector< Index >	leading_dimensions = std::vector< Index >(),
		bool	relax_if_necessary = false
	)

Delinarisation decomposition for STensor.

Parameters

in	input tensor
uncombined	basis over which the delinarisation will be performed
leading_dimensions	number of leading dimensions for threshold estimates
relax_if_necessary	Do a rank-revealing QR decomposition after each

Returns

a tuple of the number of discarded columns, the tensors P and T and the new shared basis of P (nicknamed dln-gen).

Remarks

This function is not autodifferentiable.

References syten::STensorImpl::STensor::autodiff_enabled(), syten::Tensor< rank >::b(), syten::STensorImpl::STensor::b(), syten::STensorImpl::STensor::bi(), syten::Delinearise::cols(), syten::STensorImpl::SBasis::dir(), syten::STensorImpl::SBasis::f(), syten::STensorImpl::STensor::get_bases(), syten::STensorImpl::STensor::get_fermionic_order(), if_constexpr, syten::Inc, syten::STensorImpl::STensor::move(), std::move(), SYTEN_ASSERT_MSG, SYTEN_TENSOR_RANK, and syten::STensorImpl::STensor::visit().

Here is the call graph for this function: