dbcsr_t_contract_index Subroutine

public subroutine dbcsr_t_contract_index(alpha, tensor_1, tensor_2, beta, tensor_3, contract_1, notcontract_1, contract_2, notcontract_2, map_1, map_2, bounds_1, bounds_2, bounds_3, filter_eps, nblks_local, result_index)

get indices of non-zero tensor blocks for contraction result without actually performing contraction. this is an estimate based on block norm multiplication. See documentation of dbcsr_t_contract.

Arguments

Type	Intent	Optional	Attributes		Name
type(dbcsr_scalar_type),	intent(in)			::	alpha
type(dbcsr_t_type),	intent(inout),		TARGET	::	tensor_1
type(dbcsr_t_type),	intent(inout),		TARGET	::	tensor_2
type(dbcsr_scalar_type),	intent(in)			::	beta
type(dbcsr_t_type),	intent(inout),		TARGET	::	tensor_3
integer,	intent(in),		DIMENSION(:)	::	contract_1
integer,	intent(in),		DIMENSION(:)	::	notcontract_1
integer,	intent(in),		DIMENSION(:)	::	contract_2
integer,	intent(in),		DIMENSION(:)	::	notcontract_2
integer,	intent(in),		DIMENSION(:)	::	map_1
integer,	intent(in),		DIMENSION(:)	::	map_2
integer,	intent(in),	optional,	DIMENSION(2, SIZE(contract_1))	::	bounds_1
integer,	intent(in),	optional,	DIMENSION(2, SIZE(notcontract_1))	::	bounds_2
integer,	intent(in),	optional,	DIMENSION(2, SIZE(notcontract_2))	::	bounds_3
real(kind=real_8),	intent(in),	optional		::	filter_eps
integer,	intent(out)			::	nblks_local	number of local blocks on this MPI rank
integer,	intent(out),		DIMENSION(dbcsr_t_max_nblks_local(tensor_3), ndims_tensor(tensor_3))	::	result_index	indices of local non-zero tensor blocks for tensor_3 only the elements result_index(:nblks_local, :) are relevant (all others are set to 0)