fixes error in last commit

src/analysis.jl

@@ -88,14 +88,14 @@ function get_AttributeRanking(a::approx)::Dict{Float64,Vector{Float64}}
 end
 
 function get_ActiveSet( a::approx, eps::Vector{Float64}, λ::Float64 )::Vector{Vector{Int}}
+    U = a.U[2:end]
     lengths = [ length(u) for u in U ]
     ds = maximum(lengths)
 
     if length(eps) != ds 
         error( "Entries in vector eps have to be ds.")
     end
 
-    U = a.U[2:end]
     gsi = get_GSI(a, λ)
 
     n = 0