parallel.client.view

Module: parallel.client.view

Inheritance diagram for IPython.parallel.client.view:

Views of remote engines.

Authors:

• Min RK

Classes

DirectView

class IPython.parallel.client.view.DirectView(client=None, socket=None, targets=None)

Bases: IPython.parallel.client.view.View

Direct Multiplexer View of one or more engines.

These are created via indexed access to a client:

>>> dv_1 = client[1]
>>> dv_all = client[:]
>>> dv_even = client[::2]
>>> dv_some = client[1:3]

This object provides dictionary access to engine namespaces:

# push a=5: >>> dv[‘a’] = 5 # pull ‘foo’: >>> db[‘foo’]

__init__(client=None, socket=None, targets=None)

abort(jobs=None, targets=None, block=None)

Abort jobs on my engines.

Parameters :

jobs : None, str, list of strs, optional

if None: abort all jobs. else: abort specific msg_id(s).

activate()

Make this View active for parallel magic commands.

IPython has a magic command syntax to work with MultiEngineClient objects. In a given IPython session there is a single active one. While there can be many Views created and used by the user, there is only one active one. The active View is used whenever the magic commands %px and %autopx are used.

The activate() method is called on a given View to make it active. Once this has been done, the magic commands can be used.

apply(f, *args, **kwargs)

calls f(*args, **kwargs) on remote engines, returning the result.

This method sets all apply flags via this View’s attributes.

if self.block is False:

returns AsyncResult

else:

returns actual result of f(*args, **kwargs)

apply_async(f, *args, **kwargs)

calls f(*args, **kwargs) on remote engines in a nonblocking manner.

returns AsyncResult

apply_sync(f, *args, **kwargs)

calls f(*args, **kwargs) on remote engines in a blocking manner, returning the result.

returns: actual result of f(*args, **kwargs)

block

A boolean (True, False) trait.

classmethod class_trait_names(**metadata)

Get a list of all the names of this classes traits.

This method is just like the trait_names() method, but is unbound.

classmethod class_traits(**metadata)

Get a list of all the traits of this class.

This method is just like the traits() method, but is unbound.

The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

clear(targets=None, block=False)

Clear the remote namespaces on my engines.

client

A trait whose value must be an instance of a specified class.

The value can also be an instance of a subclass of the specified class.

execute(code, targets=None, block=None)

Executes code on targets in blocking or nonblocking manner.

execute is always bound (affects engine namespace)

Parameters :

code : str

the code string to be executed

block : bool

whether or not to wait until done to return default: self.block

gather(key, dist='b', targets=None, block=None)

Gather a partitioned sequence on a set of engines as a single local seq.

get(key_s)

get object(s) by key_s from remote namespace

see pull for details.

get_result(indices_or_msg_ids=None)

return one or more results, specified by history index or msg_id.

See client.get_result for details.

history

An instance of a Python list.

imap(f, *sequences, **kwargs)

Parallel version of itertools.imap.

See self.map for details.

importer

sync_imports(local=True) as a property.

See sync_imports for details.

kill(targets=None, block=True)

Kill my engines.

map(f, *sequences, **kwargs)

view.map(f, *sequences, block=self.block) => list|AsyncMapResult

Parallel version of builtin map, using this View’s targets.

There will be one task per target, so work will be chunked if the sequences are longer than targets.

Results can be iterated as they are ready, but will become available in chunks.

Parameters :

f : callable

function to be mapped

*sequences: one or more sequences of matching length :

the sequences to be distributed and passed to f

block : bool

whether to wait for the result or not [default self.block]

Returns :

if block=False: :

AsyncMapResult

An object like AsyncResult, but which reassembles the sequence of results into a single list. AsyncMapResults can be iterated through before all results are complete.

else: :

list

the result of map(f,*sequences)

map_async(f, *sequences, **kwargs)

Parallel version of builtin map, using this view’s engines.

This is equivalent to map(...block=False)

See self.map for details.

map_sync(f, *sequences, **kwargs)

Parallel version of builtin map, using this view’s engines.

This is equivalent to map(...block=True)

See self.map for details.

on_trait_change(handler, name=None, remove=False)

Setup a handler to be called when a trait changes.

This is used to setup dynamic notifications of trait changes.

Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

Parameters :

handler : callable

A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

name : list, str, None

If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

remove : bool

If False (the default), then install the handler. If True then unintall it.

outstanding

An instance of a Python set.

parallel(dist='b', block=None, **flags)

Decorator for making a ParallelFunction

pull(names, targets=None, block=None)

get object(s) by name from remote namespace

will return one object if it is a key. can also take a list of keys, in which case it will return a list of objects.

purge_results(jobs=[], targets=[])

Instruct the controller to forget specific results.

push(ns, targets=None, block=None, track=None)

update remote namespace with dict ns

Parameters :

ns : dict

dict of keys with which to update engine namespace(s)

block : bool [default

whether to wait to be notified of engine receipt

queue_status(targets=None, verbose=False)

Fetch the Queue status of my engines

remote(block=True, **flags)

Decorator for making a RemoteFunction

results

An instance of a Python dict.

run(filename, targets=None, block=None)

Execute contents of filename on my engine(s).

This simply reads the contents of the file and calls execute.

Parameters :

filename : str

The path to the file

targets : int/str/list of ints/strs

the engines on which to execute default : all

block : bool

whether or not to wait until done default: self.block

scatter(key, seq, dist='b', flatten=False, targets=None, block=None, track=None)

Partition a Python sequence and send the partitions to a set of engines.

set_flags(**kwargs)

set my attribute flags by keyword.

Views determine behavior with a few attributes (block, track, etc.). These attributes can be set all at once by name with this method.

Parameters :

block : bool

whether to wait for results

track : bool

whether to create a MessageTracker to allow the user to safely edit after arrays and buffers during non-copying sends.

shutdown(targets=None, restart=False, hub=False, block=None)

Terminates one or more engine processes, optionally including the hub.

skip_doctest = True

spin()

spin the client, and sync

sync_imports(*args, **kwds)

Context Manager for performing simultaneous local and remote imports.

‘import x as y’ will not work. The ‘as y’ part will simply be ignored.

>>> with view.sync_imports():
...    from numpy import recarray
importing recarray from numpy on engine(s)

targets

temp_flags(*args, **kwds)

temporarily set flags, for use in with statements.

See set_flags for permanent setting of flags

Examples

>>> view.track=False
...
>>> with view.temp_flags(track=True):
...    ar = view.apply(dostuff, my_big_array)
...    ar.tracker.wait() # wait for send to finish
>>> view.track
False

track

A boolean (True, False) trait.

trait_metadata(traitname, key)

Get metadata values for trait by key.

trait_names(**metadata)

Get a list of all the names of this classes traits.

traits(**metadata)

Get a list of all the traits of this class.

The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

update(ns)

update remote namespace with dict ns

See push for details.

wait(jobs=None, timeout=-1)

waits on one or more jobs, for up to timeout seconds.

Parameters :

jobs : int, str, or list of ints and/or strs, or one or more AsyncResult objects

ints are indices to self.history strs are msg_ids default: wait on all outstanding messages

timeout : float

a time in seconds, after which to give up. default is -1, which means no timeout

Returns :

True : when all msg_ids are done

False : timeout reached, some msg_ids still outstanding

LoadBalancedView

class IPython.parallel.client.view.LoadBalancedView(client=None, socket=None, **flags)

Bases: IPython.parallel.client.view.View

An load-balancing View that only executes via the Task scheduler.

Load-balanced views can be created with the client’s view method:

>>> v = client.load_balanced_view()

or targets can be specified, to restrict the potential destinations:

>>> v = client.client.load_balanced_view(([1,3])

which would restrict loadbalancing to between engines 1 and 3.

__init__(client=None, socket=None, **flags)

abort(jobs=None, targets=None, block=None)

Abort jobs on my engines.

Parameters :

jobs : None, str, list of strs, optional

if None: abort all jobs. else: abort specific msg_id(s).

after

apply(f, *args, **kwargs)

calls f(*args, **kwargs) on remote engines, returning the result.

This method sets all apply flags via this View’s attributes.

if self.block is False:

returns AsyncResult

else:

returns actual result of f(*args, **kwargs)

apply_async(f, *args, **kwargs)

calls f(*args, **kwargs) on remote engines in a nonblocking manner.

returns AsyncResult

apply_sync(f, *args, **kwargs)

calls f(*args, **kwargs) on remote engines in a blocking manner, returning the result.

returns: actual result of f(*args, **kwargs)

block

A boolean (True, False) trait.

classmethod class_trait_names(**metadata)

Get a list of all the names of this classes traits.

This method is just like the trait_names() method, but is unbound.

classmethod class_traits(**metadata)

Get a list of all the traits of this class.

This method is just like the traits() method, but is unbound.

The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

client

A trait whose value must be an instance of a specified class.

The value can also be an instance of a subclass of the specified class.

follow

get_result(indices_or_msg_ids=None)

return one or more results, specified by history index or msg_id.

See client.get_result for details.

history

An instance of a Python list.

imap(f, *sequences, **kwargs)

Parallel version of itertools.imap.

See self.map for details.

map(f, *sequences, **kwargs)

view.map(f, *sequences, block=self.block, chunksize=1) => list|AsyncMapResult

Parallel version of builtin map, load-balanced by this View.

block, and chunksize can be specified by keyword only.

Each chunksize elements will be a separate task, and will be load-balanced. This lets individual elements be available for iteration as soon as they arrive.

Parameters :

f : callable

function to be mapped

*sequences: one or more sequences of matching length :

the sequences to be distributed and passed to f

block : bool

whether to wait for the result or not [default self.block]

track : bool

whether to create a MessageTracker to allow the user to safely edit after arrays and buffers during non-copying sends.

chunksize : int

how many elements should be in each task [default 1]

Returns :

if block=False: :

AsyncMapResult

An object like AsyncResult, but which reassembles the sequence of results into a single list. AsyncMapResults can be iterated through before all results are complete.

else:

the result of map(f,*sequences)

map_async(f, *sequences, **kwargs)

Parallel version of builtin map, using this view’s engines.

This is equivalent to map(...block=False)

See self.map for details.

map_sync(f, *sequences, **kwargs)

Parallel version of builtin map, using this view’s engines.

This is equivalent to map(...block=True)

See self.map for details.

on_trait_change(handler, name=None, remove=False)

Setup a handler to be called when a trait changes.

This is used to setup dynamic notifications of trait changes.

Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

Parameters :

handler : callable

A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

name : list, str, None

If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

remove : bool

If False (the default), then install the handler. If True then unintall it.

outstanding

An instance of a Python set.

parallel(dist='b', block=None, **flags)

Decorator for making a ParallelFunction

purge_results(jobs=[], targets=[])

Instruct the controller to forget specific results.

queue_status(targets=None, verbose=False)

Fetch the Queue status of my engines

remote(block=True, **flags)

Decorator for making a RemoteFunction

results

An instance of a Python dict.

retries

A casting version of the int trait.

set_flags(**kwargs)

set my attribute flags by keyword.

A View is a wrapper for the Client’s apply method, but with attributes that specify keyword arguments, those attributes can be set by keyword argument with this method.

Parameters :

block : bool

whether to wait for results

track : bool

whether to create a MessageTracker to allow the user to safely edit after arrays and buffers during non-copying sends.

after : Dependency or collection of msg_ids

Only for load-balanced execution (targets=None) Specify a list of msg_ids as a time-based dependency. This job will only be run after the dependencies have been met.

follow : Dependency or collection of msg_ids

Only for load-balanced execution (targets=None) Specify a list of msg_ids as a location-based dependency. This job will only be run on an engine where this dependency is met.

timeout : float/int or None

Only for load-balanced execution (targets=None) Specify an amount of time (in seconds) for the scheduler to wait for dependencies to be met before failing with a DependencyTimeout.

retries : int

Number of times a task will be retried on failure.

shutdown(targets=None, restart=False, hub=False, block=None)

Terminates one or more engine processes, optionally including the hub.

skip_doctest = True

spin()

spin the client, and sync

targets

temp_flags(*args, **kwds)

temporarily set flags, for use in with statements.

See set_flags for permanent setting of flags

Examples

>>> view.track=False
...
>>> with view.temp_flags(track=True):
...    ar = view.apply(dostuff, my_big_array)
...    ar.tracker.wait() # wait for send to finish
>>> view.track
False

timeout

A casting version of the float trait.

track

A boolean (True, False) trait.

trait_metadata(traitname, key)

Get metadata values for trait by key.

trait_names(**metadata)

Get a list of all the names of this classes traits.

traits(**metadata)

Get a list of all the traits of this class.

The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

wait(jobs=None, timeout=-1)

waits on one or more jobs, for up to timeout seconds.

Parameters :

jobs : int, str, or list of ints and/or strs, or one or more AsyncResult objects

ints are indices to self.history strs are msg_ids default: wait on all outstanding messages

timeout : float

a time in seconds, after which to give up. default is -1, which means no timeout

Returns :

True : when all msg_ids are done

False : timeout reached, some msg_ids still outstanding

View

class IPython.parallel.client.view.View(client=None, socket=None, **flags)

Bases: IPython.utils.traitlets.HasTraits

Base View class for more convenint apply(f,*args,**kwargs) syntax via attributes.

Don’t use this class, use subclasses.

Methods :

spin :

flushes incoming results and registration state changes control methods spin, and requesting ids also ensures up to date

wait :

wait on one or more msg_ids

execution methods :

apply legacy: execute, run

data movement :

push, pull, scatter, gather

query methods :

get_result, queue_status, purge_results, result_status

control methods :

abort, shutdown

__init__(client=None, socket=None, **flags)

abort(jobs=None, targets=None, block=None)

Abort jobs on my engines.

Parameters :

jobs : None, str, list of strs, optional

if None: abort all jobs. else: abort specific msg_id(s).

apply(f, *args, **kwargs)

calls f(*args, **kwargs) on remote engines, returning the result.

This method sets all apply flags via this View’s attributes.

if self.block is False:

returns AsyncResult

else:

returns actual result of f(*args, **kwargs)

apply_async(f, *args, **kwargs)

calls f(*args, **kwargs) on remote engines in a nonblocking manner.

returns AsyncResult

apply_sync(f, *args, **kwargs)

calls f(*args, **kwargs) on remote engines in a blocking manner, returning the result.

returns: actual result of f(*args, **kwargs)

block

A boolean (True, False) trait.

classmethod class_trait_names(**metadata)

Get a list of all the names of this classes traits.

This method is just like the trait_names() method, but is unbound.

classmethod class_traits(**metadata)

Get a list of all the traits of this class.

This method is just like the traits() method, but is unbound.

The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

client

A trait whose value must be an instance of a specified class.

The value can also be an instance of a subclass of the specified class.

get_result(indices_or_msg_ids=None)

return one or more results, specified by history index or msg_id.

See client.get_result for details.

history

An instance of a Python list.

imap(f, *sequences, **kwargs)

Parallel version of itertools.imap.

See self.map for details.

map(f, *sequences, **kwargs)

override in subclasses

map_async(f, *sequences, **kwargs)

Parallel version of builtin map, using this view’s engines.

This is equivalent to map(...block=False)

See self.map for details.

map_sync(f, *sequences, **kwargs)

Parallel version of builtin map, using this view’s engines.

This is equivalent to map(...block=True)

See self.map for details.

on_trait_change(handler, name=None, remove=False)

Setup a handler to be called when a trait changes.

This is used to setup dynamic notifications of trait changes.

Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

Parameters :

handler : callable

A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

name : list, str, None

If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

remove : bool

If False (the default), then install the handler. If True then unintall it.

outstanding

An instance of a Python set.

parallel(dist='b', block=None, **flags)

Decorator for making a ParallelFunction

purge_results(jobs=[], targets=[])

Instruct the controller to forget specific results.

queue_status(targets=None, verbose=False)

Fetch the Queue status of my engines

remote(block=True, **flags)

Decorator for making a RemoteFunction

results

An instance of a Python dict.

set_flags(**kwargs)

set my attribute flags by keyword.

Views determine behavior with a few attributes (block, track, etc.). These attributes can be set all at once by name with this method.

Parameters :

block : bool

whether to wait for results

track : bool

whether to create a MessageTracker to allow the user to safely edit after arrays and buffers during non-copying sends.

shutdown(targets=None, restart=False, hub=False, block=None)

Terminates one or more engine processes, optionally including the hub.

skip_doctest = True

spin()

spin the client, and sync

targets

temp_flags(*args, **kwds)

temporarily set flags, for use in with statements.

See set_flags for permanent setting of flags

Examples

>>> view.track=False
...
>>> with view.temp_flags(track=True):
...    ar = view.apply(dostuff, my_big_array)
...    ar.tracker.wait() # wait for send to finish
>>> view.track
False

track

A boolean (True, False) trait.

trait_metadata(traitname, key)

Get metadata values for trait by key.

trait_names(**metadata)

Get a list of all the names of this classes traits.

traits(**metadata)

Get a list of all the traits of this class.

The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

wait(jobs=None, timeout=-1)

waits on one or more jobs, for up to timeout seconds.

Parameters :

jobs : int, str, or list of ints and/or strs, or one or more AsyncResult objects

ints are indices to self.history strs are msg_ids default: wait on all outstanding messages

timeout : float

a time in seconds, after which to give up. default is -1, which means no timeout

Returns :

True : when all msg_ids are done

False : timeout reached, some msg_ids still outstanding

Functions

IPython.parallel.client.view.save_ids(f)

Keep our history and outstanding attributes up to date after a method call.

IPython.parallel.client.view.spin_after(f)

call spin after the method.

IPython.parallel.client.view.sync_results(f)

sync relevant results from self.client to our results attribute.