Crash on specific matrix input

Hi!

Entering the following matrix

 1 0 2 3
 0 1 0 2
 2 0 1 0
 3 2 0 1

yields an Address Boundary Error.
Running ddd on that seems to indicate that the error comes from

(anonymous namespace)::InitMinTable::fillReflectionRow (this=0x7ffff7f46650, G=..., r=5, s=2 '\002') at minroots.cpp:837

I've looked at the code at this place but couldn't easily find the source of the bug.
I'll try to look into it more carefully.

EDIT: (the matrix was input interactively)

EDIT2: After further investigation, it seems that at this line

coxeter/minroots.cpp

Line 835 in 7b5a1f0

y = min(y,s);

, the value for y is undef_minnbr, which I think shouldn't happen since we're then using it as an index.