From: Christian Bauer
Date: Fri, 11 May 2001 18:04:35 +0000 (+0000)
Subject: dirac_trace() now takes three arguments
X-Git-Tag: release_0-8-3~5
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=commitdiff_plain;h=ca09ead7889a10d651d0042cb4cf44ab4e8a177a;hp=8b3f3cb2d72aa91b9a635f63d5a4c9a24afa5b00
dirac_trace() now takes three arguments
---
diff --git a/doc/tutorial/ginac.texi b/doc/tutorial/ginac.texi
index 5117d4ae..3cb6607c 100644
--- a/doc/tutorial/ginac.texi
+++ b/doc/tutorial/ginac.texi
@@ -2053,16 +2053,18 @@ To calculate the trace of an expression containing strings of Dirac gammas
you use the function
@example
-ex dirac_trace(const ex & e, unsigned char rl = 0);
+ex dirac_trace(const ex & e, unsigned char rl = 0, const ex & trONE = 4);
@end example
This function takes the trace of all gammas with the specified representation
-label; gammas with other labels are left standing. The @code{dirac_trace()}
-function is a linear functional that is equal to the usual trace only in
-@math{D = 4} dimensions. In particular, the functional is not cyclic in
-@math{D != 4} dimensions when acting on expressions containing @samp{gamma5},
-so it's not a proper trace. This @samp{gamma5} scheme is described in greater
-detail in @cite{The Role of gamma5 in Dimensional Regularization}.
+label; gammas with other labels are left standing. The last argument to
+@code{dirac_trace()} is the value to be returned for the trace of the unity
+element, which defaults to 4. The @code{dirac_trace()} function is a linear
+functional that is equal to the usual trace only in @math{D = 4} dimensions.
+In particular, the functional is not cyclic in @math{D != 4} dimensions when
+acting on expressions containing @samp{gamma5}, so it's not a proper trace.
+This @samp{gamma5} scheme is described in greater detail in
+@cite{The Role of gamma5 in Dimensional Regularization}.
The value of the trace itself is also usually different in 4 and in
@math{D != 4} dimensions: