Closed NefedovM closed 1 year ago
Hi Maxim,
thanks a lot for this bug report. The output here is clearly incorrect, but it is also rather easy to fix, given
that now the source code of SUNSimplify
/ SUNTrace
is very clean and readable.
Please try reinstalling the dev version, the bugfix should be already there.
Cheers, Vladyslav
Hi Vladyslav, yes, after reinstalling the dev. version the
SUNTrace[SUNT[a].SUNT[b].SUNT[c] - SUNT[c].SUNT[b].SUNT[a]] SUNSimplify[%] // InputForm
produces
(I/2)*SUNF[SUNIndex[a], SUNIndex[b], SUNIndex[c]]
thank you.
All the best, Maxim
Thanks for the confirmation!
$Version ="12.0.0 for Linux x86 (64-bit) (April 7, 2019)"
$FeynCalcVersion = "10.0.0"
development version
Check the output of Import[FileNameJoin[{$UserBaseDirectory, "Kernel", "init.m"}], "String"]
Hi. I have found that evaluating SUNTrace[SUNT[a].SUNT[b].SUNT[c] - SUNT[c].SUNT[b].SUNT[a]] SUNSimplify[%] // InputForm
produces: (I/2)*SUNF[SUNIndex[FCGV["sun6891"]], SUNIndex[FCGV["sun6892"]], SUNIndex[FCGV["sun6893"]]]
while SUNTrace[SUNT[a].SUNT[b].SUNT[c]] - SUNTrace[SUNT[c].SUNT[b].SUNT[a]] SUNSimplify[%] // InputForm
produces the expected result: (I/2)*SUNF[SUNIndex[a], SUNIndex[b], SUNIndex[c]]
It seems that in the first example, the SUNSimplify have counted variables a,b,c inside SUNTrace twice, decided that these are dummy indices and have renamed them. Of course it is possible to avoid this problem by not putting more than one term into SUNTrace. But I think that linearity of the trace is a reasonable property to expect. This behavior have lead to error messages with some of my older code, which did not pop-up with FC v.9x but started to appear in v. 10.