#4115: [with patch, needs review] Double coset problems
--------------------------+-------------------------------------------------
 Reporter:  rlm           |        Owner:  rlm       
     Type:  defect        |       Status:  new       
 Priority:  major         |    Milestone:  sage-3.1.3
Component:  group_theory  |   Resolution:            
 Keywords:                |  
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Comment (by wdj):

 A couple of cool examples:-)

 {{{
 sage: P.<x> = PolynomialRing(GF(2),"x")
 sage: g = x^3+x+1
 sage: C1 = CyclicCodeFromGeneratingPolynomial(7,g); C1
 Linear code of length 7, dimension 4 over Finite Field of size 2
 sage: CW1 = matrix(GF(2),C1.list())
 sage: C2 = HammingCode(3,GF(2)); C2
 Linear code of length 7, dimension 4 over Finite Field of size 2
 sage: CW2 = matrix(GF(2),C2.list())
 sage: B = NonlinearBinaryCodeStruct(CW1)
 sage: C = NonlinearBinaryCodeStruct(CW2)
 sage: B.is_isomorphic(C)
 [0, 1, 2, 6, 5, 3, 4]
 }}}

 {{{
 sage: C1 = ExtendedQuadraticResidueCode(23,GF(2)); C1
 Linear code of length 24, dimension 12 over Finite Field of size 2
 sage: C2 = ExtendedBinaryGolayCode(); C2
 Linear code of length 24, dimension 12 over Finite Field of size 2
 sage: C1 == C2
 False
 sage: time CW1 = matrix(GF(2),C1.list())
 CPU times: user 32.98 s, sys: 0.03 s, total: 33.01 s
 Wall time: 33.12 s
 sage: time CW2 = matrix(GF(2),C2.list())
 CPU times: user 31.93 s, sys: 0.03 s, total: 31.95 s
 Wall time: 32.05 s
 sage: time B = NonlinearBinaryCodeStruct(CW1)
 CPU times: user 0.19 s, sys: 0.00 s, total: 0.19 s
 Wall time: 0.19 s
 sage: time C = NonlinearBinaryCodeStruct(CW2)
 CPU times: user 0.21 s, sys: 0.00 s, total: 0.21 s
 Wall time: 0.21 s
 sage: time B.is_isomorphic(C)
 CPU times: user 0.22 s, sys: 0.00 s, total: 0.22 s
 Wall time: 0.22 s

 [0,
  1,
  2,
  3,
  4,
  5,
  14,
  19,
  23,
  21,
  16,
  15,
  18,
  17,
  22,
  7,
  11,
  12,
  8,
  6,
  10,
  13,
  9,
  20]
 sage:
 }}}
 This is a 24x4096 matrix!

 So far so good. I'm going to try to find some more complicated examples:-)

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/4115#comment:11>
SAGE <http://sagemath.org/>
Sage - Open Source Mathematical Software: Building the Car Instead of 
Reinventing the Wheel
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