throw if dividing by a non-unit

2017-07-11 22:37:53 +02:00 · 2017-07-11 22:37:53 +02:00 · 4e213c691d
parent 7ce52c6997
commit 4e213c691d
1 changed files with 2 additions and 0 deletions
--- a/src/GroupRings.jl
+++ b/src/GroupRings.jl
@ -387,10 +387,12 @@ function divexact{T}(X::GroupRingElem{T}, Y::GroupRingElem{T})
   else
      idx = findfirst(Y)
      c = Y[idx]
+      c == 0 || throw("Can not invert")
      g = parent(Y).basis[idx]
      return X*1//c*parent(Y)(inv(g))
   end
 end
+
 ###############################################################################
 #
 #   *-involution