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Merge pull request #1063 from ioam/callable_cache

Add memoization to dynamic Callable class
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jlstevens committed Jan 16, 2017
2 parents 84d4724 + 8a701c8 commit 4deedc8bda1e992a2cf7139b3a500f2819bfaa32
Showing with 48 additions and 35 deletions.
  1. +22 −4 holoviews/core/
  2. +0 −26 holoviews/core/
  3. +2 −5 holoviews/plotting/
  4. +24 −0 tests/
@@ -404,7 +404,10 @@ class Callable(param.Parameterized):
allowing their inputs (and in future outputs) to be defined.
This makes it possible to wrap DynamicMaps with streams and
makes it possible to traverse the graph of operations applied
to a DynamicMap.
to a DynamicMap. Additionally a Callable will memoize the last
returned value based on the arguments to the function and the
state of all streams on its inputs, to avoid calling the function

callable_function = param.Callable(default=lambda x: x, doc="""
@@ -413,8 +416,22 @@ class Callable(param.Parameterized):
inputs = param.List(default=[], doc="""
The list of inputs the callable function is wrapping.""")

def __init__(self, **params):
super(Callable, self).__init__(**params)
self._memoized = {}

def __call__(self, *args, **kwargs):
return self.callable_function(*args, **kwargs)
inputs = [i for i in self.inputs if isinstance(i, DynamicMap)]
streams = [s for i in inputs for s in get_nested_streams(i)]
values = tuple(tuple(sorted(s.contents.items())) for s in streams)
key = args + tuple(sorted(kwargs.items())) + values

if key in self._memoized:
return self._memoized[key]
ret = self.callable_function(*args, **kwargs)
self._memoized = {key : ret}
return ret

def get_nested_streams(dmap):
@@ -500,6 +517,8 @@ class DynamicMap(HoloMap):

def __init__(self, callback, initial_items=None, **params):
if not isinstance(callback, (Callable, types.GeneratorType)):
callback = Callable(callable_function=callback)
super(DynamicMap, self).__init__(initial_items, callback=callback, **params)

# Set source to self if not already specified
@@ -514,7 +533,6 @@ def __init__(self, callback, initial_items=None, **params):

self.call_mode = self._validate_mode()
self.mode = 'bounded' if self.call_mode == 'key' else 'open'
self._dimensionless_cache = False

def _initial_key(self):
@@ -762,7 +780,7 @@ def __getitem__(self, key):
dimensionless = util.dimensionless_contents(get_nested_streams(self),
self.kdims, no_duplicates=False)
if (dimensionless and not self._dimensionless_cache):
if dimensionless:
raise KeyError('Using dimensionless streams disables DynamicMap cache')
cache = super(DynamicMap,self).__getitem__(key)
# Return selected cache items in a new DynamicMap
@@ -128,29 +128,3 @@ def hierarchical(keys):
hierarchies.append(store2 if hierarchy else {})
return hierarchies

class dimensionless_cache(object):
Context manager which temporarily enables lookup of frame in the
cache on a DynamicMap with dimensionless streams. Allows passing
any Dimensioned object which might contain a DynamicMap and
whether to enable the cache. This allows looking up an item
without triggering the callback. Useful when the object is looked
up multiple times as part of some processing pipeline.

def __init__(self, obj, allow_cache_lookup=True):
self.obj = obj
self._allow_cache_lookup = allow_cache_lookup

def __enter__(self):

def __exit__(self, exc_type, exc_val, exc_tb):

def set_cache_flag(self, value):
self.obj.traverse(lambda x: setattr(x, '_dimensionless_cache', value),

@@ -18,7 +18,6 @@
from ..core.options import Store, Compositor, SkipRendering
from ..core.overlay import NdOverlay
from ..core.spaces import HoloMap, DynamicMap
from ..core.traversal import dimensionless_cache
from ..core.util import stream_parameters
from ..element import Table
from .util import (get_dynamic_mode, initialize_sampled, dim_axis_label,
@@ -625,8 +624,7 @@ def _get_frame(self, key):
self.current_key = key
return self.current_frame
elif self.dynamic:
with dimensionless_cache(self.hmap, not self._force or not self.drawn):
key, frame = util.get_dynamic_item(self.hmap, self.dimensions, key)
key, frame = util.get_dynamic_item(self.hmap, self.dimensions, key)
traverse_setter(self, '_force', False)
if not isinstance(key, tuple): key = (key,)
key_map = dict(zip([ for d in self.hmap.kdims], key))
@@ -977,8 +975,7 @@ def _get_frame(self, key):
if d in item.dimensions('key')], key)
self.current_key = tuple(k[1] for k in dim_keys)
elif item.traverse(lambda x: x, [DynamicMap]):
with dimensionless_cache(item, not self._force or not self.drawn):
key, frame = util.get_dynamic_item(item, self.dimensions, key)
key, frame = util.get_dynamic_item(item, self.dimensions, key)
layout_frame[path] = frame
elif self.uniform:
@@ -1,5 +1,6 @@
import numpy as np
from holoviews import Dimension, DynamicMap, Image, HoloMap, Scatter, Curve
from holoviews.streams import PositionXY
from holoviews.util import Dynamic
from holoviews.element.comparison import ComparisonTestCase

@@ -202,3 +203,26 @@ def test_dynamic_holomap_overlay(self):
dynamic_overlay = dmap * hmap
overlaid = Image(sine_array(0,5)) * Image(sine_array(0,10))
self.assertEqual(dynamic_overlay[5], overlaid)

def test_dynamic_overlay_memoization(self):
"""Tests that Callable memoizes unchanged callbacks"""
def fn(x, y):
return Scatter([(x, y)])
dmap = DynamicMap(fn, kdims=[], streams=[PositionXY()])

counter = [0]
def fn2(x, y):
counter[0] += 1
return Image(np.random.rand(10, 10))
dmap2 = DynamicMap(fn2, kdims=[], streams=[PositionXY()])

overlaid = dmap * dmap2
overlay = overlaid[()]
self.assertEqual(overlay.Scatter.I, fn(0, 0))

dmap.event(x=1, y=2)
overlay = overlaid[()]
# Ensure dmap return value was updated
self.assertEqual(overlay.Scatter.I, fn(1, 2))
# Ensure dmap2 callback was called only once
self.assertEqual(counter[0], 1)

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