Merge branch 'master' of github.com:Jutho/TensorOperations.jl

Author: Jutho Haegeman

src/functions/ncon.jl

@@ -52,6 +52,7 @@ function ncon(tensors, network,
                 throw(ArgumentError("invalid NCON network: $network -> $output"))
         end
     end
+    (tensors,network) = resolve_traces(tensors,network);
     tree = order === nothing ? ncontree(network) : indexordertree(network, order)
 
     if sym !== nothing

src/implementation/indices.jl

@@ -34,7 +34,7 @@ Returns an array containing only those elements that appear exactly once in itr,
 and without any elements that appear more than once.
 """
 function unique2(itr)
-    out = collect(itr)
+    out = reshape(collect(itr),length(itr))
     i = 1
     while i < length(out)
         inext = _findnext(isequal(out[i]), out, i+1)

src/indexnotation/ncon.jl

@@ -81,3 +81,17 @@ function nconindexcompletion(ex)
         return ex
     end
 end
+
+
+function resolve_traces(tensors,network)
+    transformed = map(zip(tensors,network)) do (A,IA)
+        IC = unique2(IA);
+        if length(IC) == length(IA)
+            (A,IA)
+        else
+            (tensortrace(copy(A),IA,IC),IC)
+        end
+    end
+
+    first.(transformed),last.(transformed)
+end