Opened 9 years ago

Closed 8 years ago

# The Equivalence of Linear Codes

Reported by: Owned by: okazymyrov wdj minor sage-duplicate/invalid/wontfix coding theory is_permutation_equivalent Frédéric Chapoton N/A

### Description

The are exist bug in is_permutation_equivalent for LinearCode?. If dimension of code not equals to rank of a generating matrix over GF(2), then

```Traceback (most recent call last):
File "./Main.py", line 26, in <module>
cr_is_CCZ_equivalent(F='(a^5 + a^4 + a^3 + a^2)*y^32 + a^4*y^16 + (a^3 + 1)*y^8 + (a^5 + a^4 + a^2 + a)*y^4 + (a^5 + a^4 + a^3 + 1)*y^2 + (a^3 + a^2)*y',G='a^4*y^32 + (a^5 + a^4 + a^3 + a^2)*y^16 + (a^5 + a^4 + a^3 + 1)*y^8 + (a^3 + a^2 + 1)*y^4 + (a^4 + a^3 + a)*y^2 + (a^5 + a^3 + a^2 + a + 1)*y')
File "./Main.py", line 19, in cr_is_CCZ_equivalent
return CF.is_permutation_equivalent(CG)
File "/home/hamsin/bin/sage/local/lib/python2.7/site-packages/sage/misc/decorators.py", line 687, in wrapper
return func(*args, **kwds)
File "/home/hamsin/bin/sage/local/lib/python2.7/site-packages/sage/coding/linear_code.py", line 1575, in is_permutation_equivalent
CW1 = MS(self.list())
File "/home/hamsin/bin/sage/local/lib/python2.7/site-packages/sage/matrix/matrix_space.py", line 543, in __call__
return self.matrix(entries, copy=copy, coerce=coerce, rows=rows)
File "/home/hamsin/bin/sage/local/lib/python2.7/site-packages/sage/matrix/matrix_space.py", line 1372, in matrix
return self.__matrix_class(self, entries=x, copy=copy, coerce=coerce)
File "matrix_mod2_dense.pyx", line 257, in sage.matrix.matrix_mod2_dense.Matrix_mod2_dense.__init__ (sage/matrix/matrix_mod2_dense.c:3141)
IndexError: The vector of entries has the wrong length.
```

The example in the attachments.

### comment:1 Changed 8 years ago by okazymyrov

• Status changed from new to needs_review

Looks like a bug has been resolved. The previous code works fine on Mac OS X 10.8.4 with Sage 5.10.

### comment:2 Changed 8 years ago by chapoton

• Milestone changed from sage-5.11 to sage-duplicate/invalid/wontfix

### comment:3 Changed 8 years ago by chapoton

• Status changed from needs_review to positive_review

### comment:4 Changed 8 years ago by jdemeyer

• Resolution set to worksforme
• Reviewers set to Frédéric Chapoton
• Status changed from positive_review to closed
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