quimb.tensor.contraction

Functions relating to tensor network contraction.

Module Contents

Functions

get_contract_strategy()	Get the default contraction strategy - the option supplied as
set_contract_strategy(strategy)	Get the default contraction strategy - the option supplied as
contract_strategy(strategy[, set_globally])	A context manager to temporarily set the default contraction strategy
empty_symbol_map()	Get a default dictionary that will populate with symbol entries as they
inds_to_symbols(inputs)	Map a sequence of inputs terms, containing any hashable indices, to
inds_to_eq(inputs[, output])	Turn input and output indices of any sort into a single 'equation'
get_contract_backend()	Get the default backend used for tensor contractions, via 'cotengra'.
set_contract_backend(backend)	Set the default backend used for tensor contractions, via 'cotengra'.
contract_backend(backend[, set_globally])	A context manager to temporarily set the default backend used for tensor
get_tensor_linop_backend()	Get the default backend used for tensor network linear operators, via
set_tensor_linop_backend(backend)	Set the default backend used for tensor network linear operators, via
tensor_linop_backend(backend[, set_globally])	A context manager to temporarily set the default backend used for tensor
array_contract(arrays, inputs[, output, optimize, backend])
array_contract_expression(*args[, optimize])
array_contract_tree(*args[, optimize])
array_contract_path(*args[, optimize])
array_contract_pathinfo(*args, **kwargs)

Attributes

_CONTRACT_STRATEGY
_TEMP_CONTRACT_STRATEGIES
get_symbol
_CONTRACT_BACKEND
_TENSOR_LINOP_BACKEND
_TEMP_CONTRACT_BACKENDS
_TEMP_TENSOR_LINOP_BACKENDS

quimb.tensor.contraction._CONTRACT_STRATEGY = 'greedy'

quimb.tensor.contraction._TEMP_CONTRACT_STRATEGIES

quimb.tensor.contraction.get_contract_strategy()

Get the default contraction strategy - the option supplied as optimize to cotengra.

quimb.tensor.contraction.set_contract_strategy(strategy)

Get the default contraction strategy - the option supplied as optimize to cotengra.

quimb.tensor.contraction.contract_strategy(strategy, set_globally=False)

A context manager to temporarily set the default contraction strategy supplied as optimize to cotengra. By default, this only sets the contract strategy for the current thread.

Parameters:

set_globally (bool, optimize) – Whether to set the strategy just for this thread, or for all threads. If you are entering the context, then using multithreading, you might want True.

quimb.tensor.contraction.get_symbol

quimb.tensor.contraction.empty_symbol_map()

Get a default dictionary that will populate with symbol entries as they are accessed.

quimb.tensor.contraction.inds_to_symbols(inputs)

Map a sequence of inputs terms, containing any hashable indices, to single unicode letters, appropriate for einsum.

Parameters:

inputs (sequence of sequence of hashable) – The input indices per tensor.

Returns:

symbols – The mapping from index to symbol.

Return type:

dict[hashable, str]

quimb.tensor.contraction.inds_to_eq(inputs, output=None)

Turn input and output indices of any sort into a single ‘equation’ string where each index is a single ‘symbol’ (unicode character).

Parameters:

• inputs (sequence of sequence of hashable) – The input indices per tensor.

• output (sequence of hashable) – The output indices.

Returns:

eq – The string to feed to einsum/contract.

Return type:

str

quimb.tensor.contraction._CONTRACT_BACKEND

quimb.tensor.contraction._TENSOR_LINOP_BACKEND

quimb.tensor.contraction._TEMP_CONTRACT_BACKENDS

quimb.tensor.contraction._TEMP_TENSOR_LINOP_BACKENDS

quimb.tensor.contraction.get_contract_backend()

Get the default backend used for tensor contractions, via ‘cotengra’.

See also

set_contract_backend, get_tensor_linop_backend, set_tensor_linop_backend, tensor_contract

quimb.tensor.contraction.set_contract_backend(backend)

Set the default backend used for tensor contractions, via ‘cotengra’.

See also

get_contract_backend, set_tensor_linop_backend, get_tensor_linop_backend, tensor_contract

quimb.tensor.contraction.contract_backend(backend, set_globally=False)

A context manager to temporarily set the default backend used for tensor contractions, via ‘cotengra’. By default, this only sets the contract backend for the current thread.

Parameters:

set_globally (bool, optimize) – Whether to set the backend just for this thread, or for all threads. If you are entering the context, then using multithreading, you might want True.

quimb.tensor.contraction.get_tensor_linop_backend()

Get the default backend used for tensor network linear operators, via ‘cotengra’. This is different from the default contraction backend as the contractions are likely repeatedly called many times.

See also

set_tensor_linop_backend, set_contract_backend, get_contract_backend, TNLinearOperator

quimb.tensor.contraction.set_tensor_linop_backend(backend)

Set the default backend used for tensor network linear operators, via ‘cotengra’. This is different from the default contraction backend as the contractions are likely repeatedly called many times.

See also

get_tensor_linop_backend, set_contract_backend, get_contract_backend, TNLinearOperator

quimb.tensor.contraction.tensor_linop_backend(backend, set_globally=False)

A context manager to temporarily set the default backend used for tensor network linear operators, via ‘cotengra’. By default, this only sets the contract backend for the current thread.

Parameters:

set_globally (bool, optimize) – Whether to set the backend just for this thread, or for all threads. If you are entering the context, then using multithreading, you might want True.

quimb.tensor.contraction.array_contract(arrays, inputs, output=None, optimize=None, backend=None, **kwargs)

quimb.tensor.contraction.array_contract_expression(*args, optimize=None, **kwargs)

quimb.tensor.contraction.array_contract_tree(*args, optimize=None, **kwargs)

quimb.tensor.contraction.array_contract_path(*args, optimize=None, **kwargs)

quimb.tensor.contraction.array_contract_pathinfo(*args, **kwargs)