opt_einsum.path_random.RandomOptimizer

class opt_einsum.path_random.RandomOptimizer(max_repeats=32, max_time=None, minimize='flops', parallel=False, pre_dispatch=128)

Base class for running any random path finder that benefits from repeated calling, possibly in a parallel fashion. Custom random optimizers should subclass this, and the setup method should be implemented with the following signature:

def setup(self, inputs, output, size_dict):
    # custom preparation here ...
    return trial_fn, trial_args

Where trial_fn itself should have the signature:

def trial_fn(r, *trial_args):
    # custom computation of path here
    return ssa_path, cost, size

Where r is the run number and could for example be used to seed a random number generator. See RandomGreedy for an example.

Parameters

• max_repeats (int, optional) – The maximum number of repeat trials to have.

• max_time (float, optional) – The maximum amount of time to run the algorithm for.

• minimize ({‘flops’, ‘size’}, optional) – Whether to favour paths that minimize the total estimated flop-count or the size of the largest intermediate created.

• parallel ({bool, int, or executor-pool like}, optional) – Whether to parallelize the random trials, by default False. If True, use a concurrent.futures.ProcessPoolExecutor with the same number of processes as cores. If an integer is specified, use that many processes instead. Finally, you can supply a custom executor-pool which should have an API matching that of the python 3 standard library module concurrent.futures. Namely, a submit method that returns Future objects, themselves with result and cancel methods.

• pre_dispatch (int, optional) – If running in parallel, how many jobs to pre-dispatch so as to avoid submitting all jobs at once. Should also be more than twice the number of workers to avoid under-subscription. Default: 128.

Variables

• path (list[tuple[int]]) – The best path found so far.

• costs (list[int]) – The list of each trial’s costs found so far.

• sizes (list[int]) – The list of each trial’s largest intermediate size so far.

See also

RandomGreedy

__init__(max_repeats=32, max_time=None, minimize='flops', parallel=False, pre_dispatch=128)

Initialize self. See help(type(self)) for accurate signature.

Methods

__call__(inputs, output, size_dict, memory_limit)	Call self as a function.
__del__()
__delattr__(name, /)	Implement delattr(self, name).
__dir__()	Default dir() implementation.
__eq__(value, /)	Return self==value.
__format__(format_spec, /)	Default object formatter.
__ge__(value, /)	Return self>=value.
__getattribute__(name, /)	Return getattr(self, name).
__gt__(value, /)	Return self>value.
__hash__()	Return hash(self).
__init__([max_repeats, max_time, minimize, …])	Initialize self.
__init_subclass__	This method is called when a class is subclassed.
__le__(value, /)	Return self<=value.
__lt__(value, /)	Return self<value.
__ne__(value, /)	Return self!=value.
__new__(**kwargs)	Create and return a new object.
__reduce__()	Helper for pickle.
__reduce_ex__(protocol, /)	Helper for pickle.
__repr__()	Return repr(self).
__setattr__(name, value, /)	Implement setattr(self, name, value).
__sizeof__()	Size of object in memory, in bytes.
__str__()	Return str(self).
__subclasshook__	Abstract classes can override this to customize issubclass().
_cancel_futures()
_check_args_against_first_call(inputs, …)	Utility that stateful optimizers can use to ensure they are not called with different contractions across separate runs.
_gen_results_parallel(repeats, trial_fn, args)	Lazily generate results from an executor without submitting all jobs at once.
setup(inputs, output, size_dict)

Attributes

__dict__
__doc__
__module__
__weakref__	list of weak references to the object (if defined)
parallel
path	The best path found so far.