ii-vision/scheduler.py
kris 6e2c83c1e5 Introduction more general notion of update priority used to increase
weight of diffs that persist across multiple frames.

For each frame, zero out update priority of bytes that no longer have
a pending diff, and add the edit distance of the remaining diffs.

Zero these out as opcodes are retired.

Replace hamming distance with Damerau-Levenshtein distance of the
encoded pixel colours in the byte, e.g. 0x2A --> GGG0 (taking into
account the half-pixel)

This has a couple of benefits over hamming distance of the bit patterns:
- transposed pixels are weighted less (edit distance 1, not 2+ for
  Hamming)
- coloured pixels are weighted equally as white pixels (not half as
  much)
- weighting changes in palette bit that flip multiple pixel colours

While I'm here, the RLE opcode should emit run_length - 1 so that we
can encode runs of 256 bytes.
2019-03-04 23:09:00 +00:00

251 lines
9.2 KiB
Python

"""Opcode schedulers."""
import collections
from typing import Iterator
import opcodes
import random
class OpcodeScheduler:
def schedule(self, changes) -> Iterator[opcodes.Opcode]:
raise NotImplementedError
def nonce():
return random.randint(0, 255)
class HeuristicPageFirstScheduler(OpcodeScheduler):
"""Group by page first then content byte.
Grouping by page (rather than content) means that we'll reduce the window
of time during which we have violated a colour invariant due to bits
hanging across byte boundaries.
"""
# Median similarity: 0.862798 @ 15 fps, 10M output
def schedule(self, changes):
data = {}
page_weights = collections.defaultdict(int)
page_content_weights = {}
for ch in changes:
update_priority, page, offset, content, run_length = ch
data.setdefault((page, content), list()).append(
(update_priority, run_length, offset))
page_weights[page] += update_priority
page_content_weights.setdefault(page, collections.defaultdict(
int))[content] += update_priority
# Weight each page and content within page by total xor weight and
# traverse in this order, with a random nonce so that we don't
# consistently prefer higher-valued pages etc.
pages = sorted(
list(page_weights.keys()),
key=lambda p: (page_weights[p], nonce()), reverse=True)
for page in pages:
yield opcodes.SetPage(page)
content_weights = page_content_weights[page]
contents = sorted(
list(content_weights.keys()),
key=lambda c: (content_weights[c], nonce()),
reverse=True)
for content in contents:
yield opcodes.SetContent(content)
offsets = sorted(
data[(page, content)],
key=lambda x: (x[0], nonce()),
reverse=True)
# print("page %d content %d offsets %s" % (page, content,
# offsets))
for (_, run_length, offset) in offsets:
if run_length > 1:
# print("Offset %d run length %d" % (
# offset, run_length))
yield opcodes.RLE(offset, run_length)
else:
yield opcodes.Store(offset)
class HeuristicContentFirstScheduler(OpcodeScheduler):
"""Group by content first then page.
This has a fair bit of colour fringing because we aren't guaranteed to
get back to fixing up hanging bits within our frame window. In practise
this also does not deal well with fine detail at higher frame rates.
"""
def schedule(self, changes):
data = {}
content_weights = collections.defaultdict(int)
content_page_weights = {}
for ch in changes:
update_priority, page, offset, content, run_length = ch
data.setdefault((page, content), list()).append(
(update_priority, run_length, offset))
content_weights[content] += update_priority
content_page_weights.setdefault(content, collections.defaultdict(
int))[page] += update_priority
# Weight each page and content within page by total xor weight and
# traverse in this order
contents = sorted(
list(content_weights.keys()),
key=lambda p: content_weights[p], reverse=True)
for content in contents:
yield opcodes.SetContent(content)
page_weights = content_page_weights[content]
pages = sorted(
list(page_weights.keys()),
key=lambda c: page_weights[c],
reverse=True)
for page in pages:
yield opcodes.SetPage(page)
offsets = sorted(data[(page, content)], key=lambda x: x[0],
reverse=True)
# print("page %d content %d offsets %s" % (page, content,
# offsets))
for (_, run_length, offset) in offsets:
if run_length > 1:
# print("Offset %d run length %d" % (
# offset, run_length))
yield opcodes.RLE(offset, run_length)
else:
yield opcodes.Store(offset)
class OldHeuristicPageFirstScheduler(OpcodeScheduler):
"""Group by page first then content byte.
This uses a deterministic order of pages and content bytes, and ignores
update_priority altogether
"""
# Median similarity: 0.854613 ( @ 15 fps, 10M output)
# is almost as good as HeuristicPageFirstScheduler -- despite the fact
# that we consistently fail to update some pages. That means we should
# be measuring some notion of error persistence rather than just
# similarity
def schedule(self, changes):
data = {}
for ch in changes:
update_priority, page, offset, content, run_length = ch
data.setdefault(page, {}).setdefault(content, set()).add(
(run_length, offset))
for page, content_offsets in data.items():
yield opcodes.SetPage(page)
for content, offsets in content_offsets.items():
yield opcodes.SetContent(content)
# print("page %d content %d offsets %s" % (page, content,
# offsets))
for (run_length, offset) in sorted(offsets, reverse=True):
if run_length > 1:
# print("Offset %d run length %d" % (
# offset, run_length))
yield opcodes.RLE(offset, run_length)
else:
yield opcodes.Store(offset)
#
# def _tsp_opcode_scheduler(self, changes):
# # Build distance matrix for pairs of changes based on number of
# # opcodes it would cost for opcodes to emit target change given source
#
# dist = np.zeros(shape=(len(changes), len(changes)), dtype=np.int)
# for i1, ch1 in enumerate(changes):
# _, page1, _, content1 = ch1
# for i2, ch2 in enumerate(changes):
# if ch1 == ch2:
# continue
# _, page2, _, content2 = ch2
#
# cost = self.CYCLES[0] # Emit the target content byte
# if page1 != page2:
# cost += self.CYCLES[OpcodeCommand.SET_PAGE]
# if content1 != content2:
# cost += self.CYCLES[OpcodeCommand.SET_CONTENT]
#
# dist[i1][i2] = cost
# dist[i2][i1] = cost
#
# def create_distance_callback(dist_matrix):
# # Create a callback to calculate distances between cities.
#
# def distance_callback(from_node, to_node):
# return int(dist_matrix[from_node][to_node])
#
# return distance_callback
#
# routing = pywrapcp.RoutingModel(len(changes), 1, 0)
# search_parameters = pywrapcp.RoutingModel.DefaultSearchParameters()
# # Create the distance callback.
# dist_callback = create_distance_callback(dist)
# routing.SetArcCostEvaluatorOfAllVehicles(dist_callback)
#
# assignment = routing.SolveWithParameters(search_parameters)
# if assignment:
# # Solution distance.
# print("Total cycle_counter: " + str(assignment.ObjectiveValue()))
# # Display the solution.
# # Only one route here; otherwise iterate from 0 to
# # routing.vehicles() - 1
# route_number = 0
# index = routing.Start(
# route_number) # Index of the variable for the starting node.
# page = 0x20
# content = 0x7f
# # TODO: I think this will end by visiting the origin node which
# # is not what we want
# while not routing.IsEnd(index):
# _, new_page, offset, new_content = changes[index]
#
# if new_page != page:
# page = new_page
# yield self._emit(OpcodeCommand.SET_PAGE)
# yield page
#
# if new_content != content:
# content = new_content
# yield self._emit(OpcodeCommand.SET_CONTENT)
# yield content
#
# self._write(page << 8 | offset, content)
# yield self._emit(offset)
#
# index = assignment.Value(routing.NextVar(index))
# else:
# raise ValueError('No solution found.')
#
# def _heuristic_opcode_scheduler(self, changes):
# # Heuristic: group by content byte first then page
# data = {}
# for ch in changes:
# update_priority, page, offset, content = ch
# data.setdefault(content, {}).setdefault(page, set()).add(offset)
#
# for content, page_offsets in data.items():
# yield self._emit(OpcodeCommand.SET_CONTENT)
# yield content
# for page, offsets in page_offsets.items():
# yield self._emit(OpcodeCommand.SET_PAGE)
# yield page
#
# for offset in offsets:
# self._write(page << 8 | offset, content)
# yield self._emit(offset)
#