Cannot load xAct

[Edu Serna]

Ok, so I recently forgot my password for my linux account on the server I use,

I had the admin remake the account for me and I reinstalled xAct.

 I have checked I have installed the linux version in the right place and mathematica can find the documentation, 

however, when I tried to load xact:

Needs["xAct`xTensor`"]

I get:

Needs::nocont: Context xAct`xTensor` was not created when Needs was evaluated. >>

xTensor/xTensor.m

Any ideas?

Thanks for your help guys!!

[Jose]

Hi Edu,

I need further information to help you. Check that you have downloaded
the unix distribution, and not the one for windows. Then check that
the xAct directory is accessible by Mathematica, and that xAct/
xTensor.m is valid (I mean, edit the file and check that there is no
obvious problem). Try to load the package with the full path to see
whether it is a path configuration issue. When Needs cannot find a
package it gives you the Get::noopen and Needs::nocontent error
messages. Do you also get both or just the last one?

Jose.

[Edu Serna]

Hi Jose,  

Thanks for your help. I will give as much info as possible:

 I have downloaded the xAct_1.0.3.tgz for unix/linux/mac

I have extracted it in 

- single-user installation:

        $HOME/.Mathematica/Applications/

$Path gives 
{"/opt/Wolfram/Mathematica/8.0/SystemFiles/Links", \
"/home/edu/.Mathematica/Kernel", "/home/edu/.Mathematica/Autoload", \
"/home/edu/.Mathematica/Applications", \
"/usr/share/Mathematica/Kernel", "/usr/share/Mathematica/Autoload", \
"/usr/share/Mathematica/Applications", ".", "/home/edu", \
"/opt/Wolfram/Mathematica/8.0/AddOns/Packages", \
"/opt/Wolfram/Mathematica/8.0/AddOns/LegacyPackages", \
"/opt/Wolfram/Mathematica/8.0/SystemFiles/Autoload", \
"/opt/Wolfram/Mathematica/8.0/AddOns/Autoload", \
"/opt/Wolfram/Mathematica/8.0/AddOns/Applications", \
"/opt/Wolfram/Mathematica/8.0/AddOns/ExtraPackages", \
"/opt/Wolfram/Mathematica/8.0/SystemFiles/Kernel/Packages", \
"/opt/Wolfram/Mathematica/8.0/Documentation/English/System"}

I don't get the Get::noopen error message

Loading xTensor by path (I hope this is what I was supposed to do)

<< "/home/edu/.Mathematica/Applications/xAct/xTensor/xTensor.m"

gives

Needs::nocont : "Context \[NoBreak]\!\(\"xAct`xCore`\"\)\[NoBreak] \
was not created when Needs was evaluated. \!\(\*ButtonBox[\"\
\[RightSkeleton]\", ButtonStyle->\"Link\", ButtonFrame->None, \
ButtonData:>\"paclet:ref/message/Needs/nocont\", ButtonNote -> \
\"Needs::nocont\"]\)"
Needs::nocont : "Context \[NoBreak]\!\(\"xAct`xPerm`\"\)\[NoBreak] \
was not created when Needs was evaluated. \!\(\*ButtonBox[\"\
\[RightSkeleton]\", ButtonStyle->\"Link\", ButtonFrame->None, \
ButtonData:>\"paclet:ref/message/Needs/nocont\", ButtonNote -> \
\"Needs::nocont\"]\)"
xAct`xPerm`$Version::shdw : "Symbol \[NoBreak]\!\(\"$Version\"\
\)\[NoBreak] appears in multiple contexts \
\[NoBreak]\!\({\"xAct`xPerm`\", \"xAct`xTensor`\", \"System`\"}\
\)\[NoBreak]; definitions in context \[NoBreak]\!\(\"xAct`xPerm`\"\
\)\[NoBreak] may shadow or be shadowed by other definitions. \
\!\(\*ButtonBox[\"\[RightSkeleton]\", ButtonStyle->\"Link\", \
ButtonFrame->None, ButtonData:>\"paclet:ref/message/General/shdw\", \
ButtonNote -> \"xAct`xPerm`$Version::shdw\"]\)"
Last::normal : "Nonatomic expression expected at position \
\[NoBreak]\!\(1\)\[NoBreak] in \
\[NoBreak]\!\(Last[xAct`xPerm`$Version]\)\[NoBreak]. \!\(\*ButtonBox[\
\"\[RightSkeleton]\", ButtonStyle->\"Link\", ButtonFrame->None, \
ButtonData:>\"paclet:ref/message/General/normal\", ButtonNote -> \
\"Last::normal\"]\)"
General::versions : "-- Message text not found -- \
(\[NoBreak]\!\(\"xPerm\"\)\[NoBreak]) \
(\[NoBreak]\!\(xAct`xPerm`$Version\)\[NoBreak]) \
(\[NoBreak]\!\({\"1.1.1\", \(\({2011, 7, 15}\)\)}\)\[NoBreak])"
Throw::nocatch : "Uncaught \[NoBreak]\!\(Throw[Null]\)\[NoBreak] \
returned to top level. \!\(\*ButtonBox[\"\[RightSkeleton]\", \
ButtonStyle->\"Link\", ButtonFrame->None, \
ButtonData:>\"paclet:ref/message/Throw/nocatch\", ButtonNote -> \
\"Throw::nocatch\"]\)"
Hold[Throw[Null]]

Does this make any sense now? I must mention that other people have been experiencing other problems with the server.

Thanks again

[Jose]

Your command seems to be loading xTensor, but xTensor fails to load
xCore and xPerm. Hence, do one more thing now: load the packages
sequentially, to see which one generates the problem. First xCore,
then xPerm, then xTensor.

Jose.

On Apr 17, 6:48 am, Edu Serna <eduardooftheh...@gmail.com> wrote:
> Hi Jose,
>
> Thanks for your help. I will give as much info as possible:
>

>  I have downloaded the xAct_1.0.3.tgz<http://xact.es/download/xAct_1.0.3.tgz> for

[Edu Serna]

Thanks!!

Okay, so this is what I get

<< xAct`xCore`

xCore/xCore.m

<< xAct`xPerm`

xPerm/xPerm.m

<< xAct`xTensor`

xTensor/xTensor.m

There is no other message printed, I don't think that the packages are loaded as commands such as DefManifold is still blue and doesn't produce the usual verbose printing that comes with definitions associated with a manifold, it just returns the same thing.

Edu

Thanks!!!!

[Jose]

Well, I'm not sure what else to suggest. Mathematica seems to be able
to find the files, but somehow it does not read their contents. Check
that you can read the files with an editor and they don't look
corrupted. Try also for example to load any other package, like the
VectorAnalysis package, to see whether this is a generic problem with
packages or only a problem related to the xAct installation.

You said that there were other problems with that machine. It might be
worth to consult a system manager at this point...

Cheers,
Jose.

[Edu Serna]

Ok thanks very much!!!

I am messing around with the server at this point, I will try these last things you have suggested.

Edu

[Edu Serna]

I have fixed by deleting and reinstalling mathematica and xAct, seems to have worked!!