QStream – Working with quantum datastreams

class squanch.qstream.QStream(system_size, num_systems, array=None, agent=None)

Bases: object

Efficiently represents many separable quantum subsystems in a contiguous block of shared memory. QSystem``s and ``Qubit``s can be instantiated from the ``state of this class.

__init__(system_size, num_systems, array=None, agent=None)

Instantiate the quantum datastream object

Parameters:

• system_size (int) – number of entangled qubits in each quantum system; each system has dims 2^system_size
• num_systems (int) – number of small quantum systems in the data stream
• array (np.array) – pre-allocated array in memory for purposes of sharing QStreams in multiprocessing
• agent (Agent) – optional reference to the Agent owning the qstream; useful for progress monitoring across separate processes

__iter__()

Iterates over the ``QSystem``s in this class instance

Returns:each system in the stream

__len__()

Custom length method for streams; equivalent to stream.num_systems

Returns:stream.num_systems

__weakref__

list of weak references to the object (if defined)

classmethod from_array(array, reformat=False, agent=None)

Instantiates a quantum datastream object from an existing state array

Parameters:

• array (np.array) – the pre-allocated np.complex64 array representing the shared Hilbert space
• reformat (bool) – if providing a pre-allocated array, whether to reformat it to the all-zero state

Returns:

the child QStream

next()

Access the next element in the quantum stream, returning it as a QSystem object, and increment the head by 1

Returns:a QSystem for the “head” system

static reformat()

Reformats a Hilbert space array in-place to the all-zero state

Parameters:array (np.array) – a num_systems x 2^system_size x 2^system_size array of np.complex64 values

static shared_hilbert_space(num_systems)

Allocate a portion of shareable c-type memory to create a numpy array that is sharable between processes

Parameters:

• system_size (int) – number of entangled qubits in each quantum system; each has dimension 2^system_size
• num_systems (int) – number of small quantum systems in the data stream

Returns:

a blank, sharable, num_systems * 2^system_size * 2^system_size array of np.complex64 values

system(index)

Access the nth quantum system in the quantum datastream object

Parameters:index (int) – zero-index of the quantum system to access Returns:the quantum system