class GD_PQ_Bucketing(object):
def __init__(self, bucket_bounds, name = None):
if name:
self.name = name
else:
self.name = self.__class__.__name__
self.bucket_bounds = bucket_bounds
self.bucket_costs = [float(a + b)/2 for a,b in zip([0] + bucket_bounds[:-1], bucket_bounds)]
self.bucket_frac = [(0,0) for _ in bucket_bounds]
self.bucket_evictions = [0 for _ in self.bucket_bounds]
self.bucket_misses = [0 for _ in self.bucket_bounds]
self.nodes = SortedCollection(key=attrgetter("priority"))
self.H = 0
self.time = 0
self.error_numer = 0
self.error_denom = 1
def update_bucket(self, bucket_ix, new_cost):
# average of current contents
bucket_frac = self.bucket_frac[bucket_ix]
new_frac = (bucket_frac[0] + new_cost, bucket_frac[1] + 1)
self.bucket_frac[bucket_ix] = new_frac
self.bucket_costs[bucket_ix] = float(new_frac[0])/new_frac[1]
return self.bucket_costs[bucket_ix]
def touch(self, node):
self.nodes.remove(node)
b_cost = self.bucket_costs[node.bucket]
node.cost = b_cost
node.priority = (self.H + b_cost, self.time)
self.time += 1
self.error_numer += abs(b_cost - node.real_c)
self.error_denom += 1
self.nodes.insert(node)
def add_node(self, value, cost):
bucket_ix = bisect_left(self.bucket_bounds, cost)
b_cost = self.update_bucket(bucket_ix, cost)
new_node = PQNode(value, b_cost)
new_node.priority = (self.H + b_cost, self.time)
new_node.real_c = cost
new_node.bucket = bucket_ix
self.bucket_misses[bucket_ix] += cost
self.time += 1
self.nodes.insert(new_node)
self.error_numer += abs(b_cost - cost)
self.error_denom += 1
return new_node
def evict_node(self):
to_evict = self.nodes[0]
del self.nodes[0]
self.H = to_evict.cost
# update the bucket average
bucket_ix = to_evict.bucket
bucket_frac = self.bucket_frac[bucket_ix]
new_frac = (bucket_frac[0] - to_evict.real_c, bucket_frac[1] - 1)
self.bucket_frac[bucket_ix] = new_frac
if(new_frac[1] == 0):
self.bucket_costs[bucket_ix] = 0
else:
self.bucket_costs[bucket_ix] = float(new_frac[0])/new_frac[1]
self.bucket_evictions[to_evict.bucket] += to_evict.real_c
return to_evict
class GD_PQ_Bucketing_Old(object):
def __init__(self, bucket_bounds, name = None, **kwargs):
if name:
self.name = name
else:
self.name = self.__class__.__name__
self.bucket_bounds = bucket_bounds
self.bucket_costs = [float(a + b)/2 for a,b in zip([0] + bucket_bounds[:-1], bucket_bounds)]
self.bucket_frac = [(0,0) for _ in bucket_bounds]
self.nodes = SortedCollection(key=self.objective_f)
self.H = 0
self.time = 0
def objective_f(self, node):
node_L, bucket_ix = node.cost
return (self.bucket_costs[bucket_ix] + node_L, node.priority) # such an absurd objf.
def update_ordering(self):
# self.nodes.key = self.objective_f # will resort the collection.
pass
def update_bucket(self, bucket_ix, new_cost):
# default:: just set bucket to newest.
# self.bucket_costs[bucket_ix] = float(new_cost)
# do a moving window?
bucket_frac = self.bucket_frac[bucket_ix]
new_frac = (bucket_frac[0] + new_cost, bucket_frac[1] + 1)
self.bucket_frac[bucket_ix] = new_frac
self.bucket_costs[bucket_ix] = float(new_frac[0])/new_frac[1]
return self.bucket_costs[bucket_ix]
def touch(self, node):
self.nodes.remove(node)
node.cost = (self.H, node.cost[1])
node.priority = self.time
self.time += 1
self.nodes.insert(node)
def add_node(self, value, cost):
bucket_ix = bisect_left(self.bucket_bounds, cost)
self.update_bucket(bucket_ix, cost)
self.update_ordering()
new_node = PQNode(value, (self.H, bucket_ix))
new_node.priority = self.time
new_node.real_c = cost
self.time += 1
self.nodes.insert(new_node)
return new_node
def evict_node(self):
to_evict = self.nodes[0]
del self.nodes[0]
self.H = self.objective_f(to_evict)[0]
# update the bucket average
bucket_ix = to_evict.cost[1]
bucket_frac = self.bucket_frac[bucket_ix]
new_frac = (bucket_frac[0] - to_evict.real_c, bucket_frac[1] - 1)
self.bucket_frac[bucket_ix] = new_frac
if(new_frac[1] == 0):
self.bucket_costs[bucket_ix] = 0
else:
self.bucket_costs[bucket_ix] = float(new_frac[0])/new_frac[1]
self.update_ordering()
return to_evict