def _active_locations(self, address):
"""
Return a list containing the indices of the activated locations.
:param address: array of bits in {0, 1}
:type address: numpy.array
:rtype: numpy.array
"""
return (numpy.inner(self.hard_addresses,
helper.convert(address)) >=
self.activation_threshold)
def store(self, words):
"""
Store a stack of words in the memory.
Importat: Everytime this method is called it clears the content of
the memory and add the new content based on the words parameter.
:param words: a matrix in which each line is a word in {0, 1}
:type words: numpy.array
"""
data = helper.convert(words)
size, word_length = words.shape
self.content = ((1 / word_length) * numpy.dot(data.T, data) -
(size / word_length) * numpy.identity(word_length))
def store(self, address, word):
"""
Store a word in a given address in the memory.
:param address: array of bits in {0, 1}
:param word: array of bits in {0, 1}
:type address: numpy.array
:type word: numpy.array
"""
active = self._active_locations(address)
self.content[active] = numpy.clip(
self.content[active] + helper.convert(word),
-self.counter_range,
self.counter_range)
def retrieve(self, probe):
"""
Retrieve a word stored in the memory given a probe vector.
:param probe: array of bits in {0, 1}
:type probe: numpy.array
:rtype: numpy.array
"""
assert len(probe) == len(self.content)
word = numpy.array(helper.convert(probe))
word_length = len(word)
for i in numpy.random.permutation(xrange(word_length)):
temp = 0
while temp - word[i] != 0:
temp = word[i]
word[i] = numpy.sign(numpy.dot(self.content[i], word))
return helper.bitify(word)
def __init__(self, memory_size, address_length, word_length,
activation_radius):
"""
:param memory_size: number of hard locations
:param address_length: size of each address
:param word_length: size of the bit word
:param activation_radius: radius of activatio
:type memory_size: int
:type address_length: int
:type word_length: int
:type activation_radius: int
"""
self.hard_addresses = helper.convert(
numpy.random.randint(0, 2, (memory_size, address_length)))
self.activation_threshold = address_length - 2 * activation_radius
self.counter_range = numpy.ones(word_length) * 15
self.content = numpy.zeros((memory_size, word_length),
dtype=numpy.int8)
