diff --git a/src/GroupRings.jl b/src/GroupRings.jl
index 50f96e6..6fb6f32 100644
--- a/src/GroupRings.jl
+++ b/src/GroupRings.jl
@@ -1,3 +1,4 @@
+__precompile__()
 module GroupRings
 
 using Nemo
@@ -345,8 +346,8 @@ doc"""
                  X::AbstractVector,
                  Y::AbstractVector,
                 pm::Array{Int,2})
-> The most specialised multiplication for `X` and `Y` (`coeffs` of
-> `GroupRingElems`) using multiplication table `pm`.
+> The most specialised multiplication for `X` and `Y` (intended for `coeffs` of
+> `GroupRingElems`), using multiplication table `pm`.
 > Notes:
 > * this method will silently produce false results if `X[k]` is non-zero for
 > `k > size(pm,1)`.
@@ -383,7 +384,7 @@ doc"""
 > In-place multiplication for `GroupRingElem`s `X` and `Y`.
 > `mul!` will make use the initialised entries of `pm` attribute of
 > `parent(X)::GroupRing` (if available), and will compute and store in `pm` the
-> remaining products.
+> remaining products necessary to perform the multiplication.
 > The method will fail with `KeyError` if product `X*Y` is not supported on
 > `parent(X).basis`.
 """
@@ -418,9 +419,9 @@ function mul!{T}(result::GroupRingElem{T}, X::GroupRingElem, Y::GroupRingElem)
          end
       end
    else
-      for j::Int in 1:lY
+      for j in 1:lY
          if Y.coeffs[j] != z
-            for i::Int in 1:lX
+            for i in 1:lX
                if X.coeffs[i] != z
                   result[RG.basis[i]*RG.basis[j]] += X[i]*Y[j]
                end