[GAP Forum] bug in LLLReducedGramMat?

[Benjamin Sambale]

Dear GAP people,

the command LLLReducedGramMat is supposed to perform the LLL reduction 
algorithm for symmetric square matrices. Most of the time I'm satisfied 
with the output, but now I ran into the following:

M:=
[ [  4,  1,  1,  1,  8 ],
   [  1,  2,  2,  2,  2 ],
   [  1,  2,  2,  2,  2 ],
   [  1,  2,  2,  2,  2 ],
   [  8,  2,  2,  2,  4 ] ];
LLLReducedGramMat(M);
Error, List Element: <list>[2] must have an assigned value

The matrix M is symmetric, but not invertible. However, this is 
certainly not the problem here, since even a zero matrix gives no error. 
It seems to me that there is a very subtle detail strongly related to 
this matrix which goes wrong. Btw, I'm using GAP 4.7.8 under linux.

Best wishes,
Benjamin