Name: Vladyslav Shtabovenko (email_not_shown)
Date: 07/15/15-12:38:16 PM Z


Hi,

the reason for this behavior is that FeynCalc versions
4.x - 8.x were doing many "weird" things with Contexts.

When FeynCalc 4 got splitted into many separate files (before it was
just one big .m file), we (unfortunately) chose not the best way how
to load the context of those files. Essentially, each function was a
separate file and each file was a separate package. This way, when the
user was issuing

<<HighEnergyPhysics`FeynCalc`,System`

he was actually loading hundreds of the packages into MMA's ContextPath.
This loading system was also very error-prone because a missing
MakeContext in a "package"-file could easily break the whole code
inside. This is why in FeynCalc 9 (following Rolf's idea) all this
context stuff was kicked out in favor of one package with one context
splitted into many files, where the files are loaded in the same way as
in the JLink package.

If you really want to stick to FeynCalc 8.2, I guess there is no other
way as to address the functions you need directly with the full context,
e.g.

HighEnergyPhysics`FeynCalc`GA`GA

instead of just GA. Have a look at the FaRe package that also uses "old"
FeynCalc. This is how they do it there:

https://github.com/mrf1g12/FaRe/blob/master/FaRe.m

Cheers,
Vladyslav

The point was

Am 15.07.2015 um 02:32 schrieb zhang:
> Hi, everyone,
>
> I use FeynCalc8.2.0 in mathematica 8.
>
> I want to define some functions in the context test`.
> In the definitions of those functions, I want to
> use some functions in FeynCalc. Besides, functions
> in test` and functions in FeynCalc` can be used together.
>
> However, BeginPackage["test`", "HighEnergyPhysics`FeynCalc`"]
> leads to $ContextPath {test`,HighEnergyPhysics`FeynCalc`,System`},
> functions such as GA, SP etc are undefined in this $ContextPath.
>
> If we load FeynCalc in test`Private`,i.e.,
> BeginPackage["test`"]
> ...
> Begin["`Private`"]
> Needs["HighEnergyPhysics`FeynCalc`"]
> ...
> ...
> EndPackage[]
> Then in the context text`, GA etc can be used.
> But how should we load FeynCalc outside test`?
> Needs["HighEnergyPhysics`FeynCalc`"] only
> add "HighEnergyPhysics`FeynCalc`" to $ContextPath!
>
> Thanks
>
> zhang
>



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