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#!/usr/bin/env python
#
# Copyright 2015 Free Software Foundation, Inc.
#
# GNU Radio is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
#
# GNU Radio is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GNU Radio; see the file COPYING. If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
#
import numpy as np
from channel_construction_bec import get_bec_frozen_indices
def is_power_of_two(num):
if type(num) != int:
return False # make sure we only compute integers.
return num != 0 and ((num & (num - 1)) == 0)
def bit_reverse(value, n):
# is this really missing in NumPy???
seq = np.int(value)
rev = np.int(0)
rmask = np.int(1)
lmask = np.int(2 ** (n - 1))
for i in range(n // 2):
shiftval = n - 1 - (i * 2)
rshift = np.left_shift(np.bitwise_and(seq, rmask), shiftval)
lshift = np.right_shift(np.bitwise_and(seq, lmask), shiftval)
rev = np.bitwise_or(rev, rshift)
rev = np.bitwise_or(rev, lshift)
rmask = np.left_shift(rmask, 1)
lmask = np.right_shift(lmask, 1)
if not n % 2 == 0:
rev = np.bitwise_or(rev, np.bitwise_and(seq, rmask))
return rev
def bit_reverse_vector(vec, n):
return np.array([bit_reverse(e, n) for e in vec], dtype=vec.dtype)
def unpack_byte(byte, nactive):
if np.amin(byte) < 0 or np.amax(byte) > 255:
return None
if not byte.dtype == np.uint8:
byte = byte.astype(np.uint8)
if nactive == 0:
return np.array([], dtype=np.uint8)
return np.unpackbits(byte)[-nactive:]
def pack_byte(bits):
if len(bits) == 0:
return 0
if np.amin(bits) < 0 or np.amax(bits) > 1: # only '1' and '0' in bits array allowed!
return None
bits = np.concatenate((np.zeros(8 - len(bits), dtype=np.uint8), bits))
res = np.packbits(bits)[0]
return res
def get_frozen_bit_positions(directory, n, k, p):
import glob, os
if not os.getcwd().endswith(directory):
os.chdir(directory)
prefix = 'frozen_bit_positions_'
prefix_len = len(prefix)
for file in glob.glob("*.npy"):
if file.find(prefix) < 0:
continue
filename = file
file = file[file.find(prefix) + prefix_len:]
file = file[:-4]
file = file.split('_')
nstr = [x for x in file if x.startswith('n')]
kstr = [x for x in file if x.startswith('k')]
pstr = [x for x in file if x.startswith('p')]
nstr = int(nstr[0][1:])
kstr = int(kstr[0][1:])
pstr = float(pstr[0][1:])
if n == nstr and k == kstr:
return np.load(filename)
return get_bec_frozen_indices(n, k, p)
def main():
print 'helper functions'
for i in range(8):
print(i, 'is power of 2: ', is_power_of_two(i))
n = 2 ** 6
k = n // 2
eta = 0.3
# frozen_bit_positions = get_frozen_bit_positions('.', 256, 128, 0.11)
# print(frozen_bit_positions)
print(np.arange(16))
print bit_reverse_vector(np.arange(16), 4)
if __name__ == '__main__':
main()
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