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*                                            *
*  INSTALLATION NOTES FOR THE xTras PACKAGE  *
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The directory structure of xTras is

/
  INSTALL				(this file)
  LICENSE
  xAct/
    xTras/				(copy this subdirectory into your xAct directory)
      Kernel/
        init.m
      Documentation/	(built-in documentation that integrates with Mathematica's Documentation Center)
        English/
          ...
      Interface.m		(package files)
      PacletInfo.m
      xCore.m
      xTensor.m
      xPert.m
      Invar.m
      xCoba.m
      Algebra.m
      Combinatorics.m
      xTras.history		(changelog)

The "xTras" subdirectory must be copied in its entirety into the directory where you've installed 
the main xAct bundle (which can be downloaded from www.xact.es).
The xAct directory is most likely the following on the respective operating systems:

Linux:
  - system-wide installation (requires root privileges):
      /usr/share/Mathematica/Applications/xAct/
  - single-user installation:
      $HOME/.Mathematica/Applications/xAct/

Mac OS:
  - system-wide installation (requires root privileges):
      /Library/Mathematica/Applications/xAct/
  - single-user installation:
      /Users/<user>/Library/Mathematica/Applications/xAct/

MSWindows:
  - system-wide installation:
      C:\Documents and settings\All Users\Application data\Mathematica\Applications\xAct\
  - single-user installation:
      C:\Documents and settings\<user>\Application Data\Mathematica\Applications\xAct\

Beware that in Windows these directories might be hidden!
After installation, the package can be loaded with

   <<xAct`xTras`

Note that some functionality of xTras requires the presence of the Invar database.
This database can be downloaded from www.xact.es/Invar, and its installation 
instructions can be found at http://xact.es/Invar/Invar.Readme