col_w = 3
row_w = 6
N=1200
numIter = 20
noiseDensity = .058
######################################################################
#
# You probably should not need to change anything below this point.
#
######################################################################
K=N*col_w/row_w
E=(N-K)*row_w
L=CodeMaker.make_H_gallager(N,col_w,row_w)
code = pycodes.pyLDPC.LDPCCode(N,K,E,L)
c = [0]*N
ev = channels.BSCOutput(c,noiseDensity)
code.setevidence(ev,alg='default')
for i in range(numIter):
code.decode()
beliefs = code.getbeliefs()
bitDiffs = reduce(lambda x,y: x+y,map(lambda z: z > 0.5,beliefs))
print `bitDiffs` + ' bits wrong after ' + `numIter` + ' iterations.'
N=[120,1200, 12000, 120000]
col_w = [3]*len(N)
row_w = [6]*len(N)
leftDegrees = {2:0.33241, 3:.24632, 4:.11014, 6:0.31112}
rightDegrees = {6:.76611, 7:.23389}
# the following degree distribution is from Luby, Mitzenmacher et al. ISIT '98
# it doesn't seem to work...
#leftDegrees = {3:.44506, 5:.26704, 9:0.14835, 17:.07854, 33:0.04046,65:0.02055}
#rightDegrees = {7:.35282,8:.29548,19:.10225, 20:0.18321,84:0.04179,85:0.02445}
K=map(lambda n,c,r: n*c/r,N,col_w,row_w)
L_r=map(lambda n,c,r: CodeMaker.make_H_gallager(n,c,r),N,col_w,row_w)
E_r=map(lambda n,k,r: (n-k)*r,N,K,row_w)
L_i=map(lambda n,k: CodeMaker.MakeIrregularLDPCCodeFromLambdaRho
(n,k,leftDegrees,rightDegrees),N,K)
def CountEdges(linkArray):
return reduce(lambda x,y: x+y, map(len,linkArray))
E_i=map(CountEdges,L_i)
numSteps = [10]*len(N)
numToErase = map(lambda n,k,ns:
range(round((n-k)*1.025),round(k*1.175),round(.15*k/ns)),
N,K,numSteps)
numTimes = map(lambda x: [250]*len(x),numToErase)
"""
This module contains various regression tests designed to make sure
channel decoding functions are working correctly.
"""
import pycodes
from pycodes.utils import channels, CodeMaker, testing
from math import exp
(N,K) = (1200,600)
L = CodeMaker.make_H_gallager(N,3,6)
E = (N-K)*6 # number of edges in the code graph
testing.RequireSuccessfulDecoding(
'Small BEC test decoded with SumProductBP',
N,K,E,L,'erasures',0.35,channels.BECOutput,
numTrials=50,maxIter=20,algorithm='SumProductBP',requiredSuccessRate=0.8)
testing.RequireSuccessfulDecoding(
'Small BEC test decoded with LRSumProductBP',
N,K,E,L,'erasures',0.35,
lambda x,y: map(lambda z: exp(min(z,10)),channels.BECOutput(x,y)),
numTrials=50,maxIter=20,algorithm='LRSumProductBP',
requiredSuccessRate=0.8)
import random
from pycodes.utils import CodeMaker
from pycodes.utils.channel_coding_perf import *
from pycodes.utils.channels import BSCOutput
seed = random.getstate()
random.setstate(seed)
print 'using seed', seed
col_w = 3
row_w = 6
N = 1002
K = N * col_w / row_w
E = (N - K) * row_w
L = CodeMaker.make_H_gallager(N, col_w, row_w)
noiseDensity = [0.08, 0.06, 0.04]
numTrials = [250] * len(noiseDensity)
maxIter = 20
tester = Tester([
CodeParams(N,
K,
E,
L,
'small test',
'bit flips',
noiseDensity,
BSCOutput,
numTrials,
maxIter,