Source code for pacman.model.routing_info.base_key_and_mask

# Copyright (c) 2015 The University of Manchester
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.

import numpy
from pacman.exceptions import PacmanConfigurationException

[docs]class BaseKeyAndMask(object): """ A Key and Mask to be used for routing. """ __slots__ = [ # The routing key "_base_key", # The routing mask "_mask" ] def __init__(self, base_key, mask): """ :param int base_key: The routing key :param int mask: The routing mask :raise PacmanConfigurationException: If key & mask != key i.e. the key is not valid for the given mask """ self._base_key = base_key self._mask = mask if base_key & mask != base_key: raise PacmanConfigurationException( f"This routing info is invalid as the mask {hex(mask)} and " f"key {hex(base_key)} together alters the key") @property def key(self): """ The base key. :rtype: int """ return self._base_key @property def key_combo(self): """ The key combined with the mask. :rtype: int """ return self._base_key & self._mask @property def mask(self): """ The mask. :rtype: int """ return self._mask def __eq__(self, key_and_mask): if not isinstance(key_and_mask, BaseKeyAndMask): return False return (self._base_key == key_and_mask.key and self._mask == key_and_mask.mask) def __ne__(self, other): return not self.__eq__(other) def __repr__(self): return f"KeyAndMask:0x{self._base_key:x}:0x{self._mask:x}" def __str__(self): return self.__repr__() def __hash__(self): return self.__repr__().__hash__() @property def n_keys(self): """ The total number of keys that can be generated given the mask. :rtype: int """ # converts mask into array of bit representation unwrapped_mask = numpy.unpackbits( numpy.asarray([self._mask], dtype=">u4").view(dtype="uint8")) # how many zeros are in the bit representation array zeros = numpy.where(unwrapped_mask == 0)[0] # number of keys available from this mask size return 2 ** len(zeros)
[docs] def get_keys(self, key_array=None, offset=0, n_keys=None): """ Get the ordered list of keys that the combination allows. :param ~numpy.ndarray(int) key_array: Optional array into which the returned keys will be placed :param int offset: Optional offset into the array at which to start placing keys :param int n_keys: Optional limit on the number of keys returned. If less than this number of keys are available, only the keys available will be added :return: A tuple of an array of keys and the number of keys added to the array :rtype: tuple(~numpy.ndarray(int), int) """ # Get the position of the zeros in the mask - assume 32-bits unwrapped_mask = numpy.unpackbits( numpy.asarray([self._mask], dtype=">u4").view(dtype="uint8")) zeros = numpy.where(unwrapped_mask == 0)[0] # If there are no zeros, there is only one key in the range, so # return that if len(zeros) == 0: if key_array is None: key_array = numpy.zeros(1, dtype=">u4") key_array[offset] = self._base_key return key_array, 1 # We now know how many values there are - 2^len(zeros) max_n_keys = 2 ** len(zeros) if key_array is not None and len(key_array) < max_n_keys: max_n_keys = len(key_array) if n_keys is None or n_keys > max_n_keys: n_keys = max_n_keys if key_array is None: key_array = numpy.zeros(n_keys, dtype=">u4") # Create a list of 2^len(zeros) keys unwrapped_key = numpy.unpackbits( numpy.asarray([self._base_key], dtype=">u4").view(dtype="uint8")) # for each key, create its key with the idea of a neuron ID being # continuous and live at an offset position from the bottom of # the key for value in range(n_keys): key = numpy.copy(unwrapped_key) unwrapped_value = numpy.unpackbits( numpy.asarray([value], dtype=">u4") .view(dtype="uint8"))[-len(zeros):] key[zeros] = unwrapped_value key_array[value + offset] = \ numpy.packbits(key).view(dtype=">u4")[0].item() return key_array, n_keys