From 7deccf59f23c4cb0a3422b29a93d81bf4e2f1ed1 Mon Sep 17 00:00:00 2001
From: Vladyslav Shtabovenko <v.shtabovenko@tum.de>
Date: Wed, 6 Jan 2016 03:05:59 +0100
Subject: [PATCH] Improved Uncontract to work with tensors (using DataType
 FCTensor) that are not defined in the Global` context.

---
 FeynCalc/Lorentz/TensorFunction.m | 2 ++
 FeynCalc/Lorentz/Uncontract.m     | 4 ++--
 FeynCalc/Shared/DataType.m        | 3 +++
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/FeynCalc/Lorentz/TensorFunction.m b/FeynCalc/Lorentz/TensorFunction.m
index 9f1ed9d32..a196bec08 100755
--- a/FeynCalc/Lorentz/TensorFunction.m
+++ b/FeynCalc/Lorentz/TensorFunction.m
@@ -40,6 +40,8 @@
 			at = Last[ef],
 			f = ef
 		];
+		DataType[ef,FCTensor]=True;
+
 		With[ {tf = f},
 			If [at=!="",
 				Which[
diff --git a/FeynCalc/Lorentz/Uncontract.m b/FeynCalc/Lorentz/Uncontract.m
index edd741449..5801325b3 100755
--- a/FeynCalc/Lorentz/Uncontract.m
+++ b/FeynCalc/Lorentz/Uncontract.m
@@ -122,8 +122,8 @@
 						Pair[Momentum[c,dimSelect[d]], li] Pair[Momentum[pe,dimSelect[d]],lidr[li]])/;MemberQ[par,pe]} /. times -> Times;
 
 				(* Uncontract tensor functions *)
-				If[ !FreeQ[nex, (tf_/;Context[tf]==="Global`")[___,Momentum[(q | Polarization[q,__]),___],___]],
-					nex = nex //. { (tf_/;Context[tf]==="Global`")[a___,Momentum[(c: q | Polarization[q,__]),d_:4],b___] :>
+				If[ !FreeQ[nex, (tf_/;DataType[tf,FCTensor])[___,Momentum[(q | Polarization[q,__]),___],___]],
+					nex = nex //. { (tf_/;DataType[tf,FCTensor])[a___,Momentum[(c: q | Polarization[q,__]),d_:4],b___] :>
 						(li = LorentzIndex[a$AL[inc = inc+1],dimSelect[d]];
 						tf[a, li, b] Pair[Momentum[c,dimSelect[d]],lidr[li]])}
 				];
diff --git a/FeynCalc/Shared/DataType.m b/FeynCalc/Shared/DataType.m
index 9c0175226..2b3f03b7a 100644
--- a/FeynCalc/Shared/DataType.m
+++ b/FeynCalc/Shared/DataType.m
@@ -25,6 +25,9 @@
 PositiveNumber::usage =  "PositiveNumber is a data type. E.g. \
 DataType[Epsilon, PositiveNumber] = True (by default). ";
 
+FCTensor::usage =  "FCTensor is a data type. E.g. \
+DataType[R, FCTensor] = True. ";
+
 DataType::usage =
 "DataType[exp, type] = True   defines the object exp to have datatype type. \
 DataType[exp1, exp2, ..., type] defines the objects exp1, exp2, ... to \