Fixed a bug in FCLoopFindIntegralMappings for some rare cases for

integrals with numerators.

Author: vsht

FeynCalc/LoopIntegrals/FCLoopFindIntegralMappings.m

@@ -56,13 +56,22 @@
 fcfpmVerbose::usage = "";
 lhs::usage ="";
 
+(*
+	Here it is crucial to compare not only U and F but also the reordered propagator powers.
+	Otherwise, there might be cases, where the Feynman parameter related to e.g. a scalar product
+	in the numerator cancels out from U and F so that one would match different integrals to each
+	other
+*)
+
 Options[FCLoopFindIntegralMappings] = {
 	CharacteristicPolynomial	-> Function[{U,F}, U+F],
 	FCE 						-> False,
 	FCI 						-> False,
 	FCVerbose 					-> False,
 	FinalSubstitutions			-> {},
-	Function					-> Function[{U, F, charPoly, pows, head, int, sigma}, {head[int, Transpose[pows]], head[ExpandAll[U], ExpandAll[F]]}],
+
+	Function					-> Function[{U, F, charPoly, pows, head, int, sigma},
+										{head[int, Transpose[pows]], head[ExpandAll[U], ExpandAll[F],Transpose[pows][[3]]]}],
 	List						-> False,
 	LightPak					-> False,
 	PreferredIntegrals			-> {}
@@ -124,6 +133,7 @@
 		time=AbsoluteTime[];
 		FCPrint[1, "FCLoopFindIntegralMappings: Extracting the mappings.", FCDoControl -> fcfpmVerbose];
 		(* 2nd element are the grouped mappings *)
+
 		res = Reap[(Sow[Sequence @@ #] & /@ pakFormInts), _][[2]];
 
 		If[	!FreeQ[expr,FCTopology],

Tests/LoopIntegrals/FCLoopFindIntegralMappings.test

@@ -519,5 +519,22 @@ tmp = FCLoopFindIntegralMappings[{GLI[
 	Hold[SPD][nb] -> 0, Hold[SPD][n, nb] -> 2}, {}]}];
 $ParallelizeFeynCalc = False; tmp",
 "{{}, {GLI[topology10, {1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0}],
-GLI[topology10, {1, 1, 1, 1, 1, 0, 0, 2, 0, 0, 0, 0}]}}"}
+GLI[topology10, {1, 1, 1, 1, 1, 0, 0, 2, 0, 0, 0, 0}]}}"},
+
+{"fcstFCLoopFindIntegralMappings-ID15",
+"FCLoopFindIntegralMappings[{GLI[
+fctopology10C, {1, 0, 1, 1, 1, 0, -1}],
+GLI[fctopology10C, {1, 0, 1, 1, 1, 0, 0}]},
+{FCTopology[
+	fctopology10C, {SFAD[{{k1, 0}, {0, 1}, 1}],
+	SFAD[{{k1 + q1, 0}, {0, 1}, 1}], SFAD[{{k2, 0}, {mt^2, 1}, 1}],
+	SFAD[{{k2 + q2, 0}, {mt^2, 1}, 1}],
+	SFAD[{{k1 + k2, 0}, {mt^2, 1}, 1}],
+	SFAD[{{k1 + k2 + q1 + q2, 0}, {mt^2, 1}, 1}],
+	SFAD[{{0, k1 . q2}, {0, 1}, 1}]}, {k1, k2}, {q1,
+	q2}, {Hold[Pair][Momentum[q1, D], Momentum[q1, D]] -> 0,
+	Hold[Pair][Momentum[q2, D], Momentum[q2, D]] -> 0,
+	Hold[Pair][Momentum[q1, D], Momentum[q2, D]] -> s/2}, {}]}]",
+	"{{}, {GLI[fctopology10C, {1, 0, 1, 1, 1, 0, -1}], GLI[fctopology10C, {1, 0, 1, 1, 1, 0, 0}]}}"
+}
 });