  
  [1X6 [33X[0;0YRemarks on technical problems and the implementation[133X[101X
  
  
  [1X6.1 [33X[0;0YMaking the HeLP-package run[133X[101X
  
  [33X[0;0YFor  all  basic  functionalities  of the HeLP-package (using only the solver
  normaliz)  the  standard  GAP-installation should suffice to make everything
  work:     Get     the    most    recent    GAP    from    the    GAP-webpage
  ([7Xhttp://www.gap-system.org/[107X)   by   following   the   instructions   on  the
  Download-page.  Make  sure  to  also run [9XInstPackages.sh[109X as explained there.
  This should install all packages needed to run HeLP. Just start GAP and type
  [9XLoadPackage("HeLP");[109X.  In  GAP 4.8.2 the NormalizInterface has to be updated
  to   version  0.9.6  or  newer  which  can  be  obtained  from  the  website
  ([7Xhttp://gap-packages.github.io/NormalizInterface//[107X)  of the package. For GAP
  4.8.3 or newer this should not be necessary anymore.[133X
  
  [33X[0;0YHere  is  a  checklist  what to do, if the package does not work or you also
  want to use the solver 4ti2:[133X
  
  [30X    [33X[0;6YMake  sure  you  have  sufficiently  new  versions  of  the  following
        software:[133X
  
        [30X    [33X[0;12YGAP ([7Xhttp://www.gap-system.org/[107X) (at least 4.8.2)[133X
  
        [30X    [33X[0;12Ythe                      GAP-package                     CTblLib
              ([7Xhttp://www.math.rwth-aachen.de/~Thomas.Breuer/ctbllib/[107X)     (at
              least 1.2.2)[133X
  
        [30X    [33X[0;12Ythe GAP-package IO ([7Xhttp://gap-packages.github.io/io/[107X) (at least
              4.2;  see  also the next bullet point if this package can not be
              loaded)[133X
  
        [30X    [33X[0;12Ythe                   GAP-package                  4ti2Interface
              (
              http://wwwb.math.rwth-aachen.de/~gutsche/gap_packages/4ti2Interface/
              ) (at least 2015.04.29; this package needs the IO-package)[133X
  
        [30X    [33X[0;12Ythe                 GAP-package                NormalizInterface
              ([7Xhttp://gap-packages.github.io/NormalizInterface//[107X)   (at  least
              0.9.6)[133X
  
              [33X[0;12YUsually  all  these  packages  should  come  with a sufficiently
              recent GAP-installation (4.8.2 or newer) and should be contained
              in  the  pkg-folder  of the GAP-installation. To see if they are
              working you can load them by typing [9XLoadPackage("[name]");[109X after
              starting GAP, where [9X[name][109X is the name of the package.[133X
  
  [30X    [33X[0;6YThe  IO-package  needs  a  C-part  to  be compiled. To see if this has
        already  been  done  on  your system, you can enter [9XLoadPackage("IO");[109X
        after starting GAP. If the result is [9Xfail[109X and the package is contained
        in  the  pkg-folder,  than most likely the C-part is not yet compiled.
        For  information  on  installation and in particular on how to compile
        the            C-part,            see            the            manual
        ([7Xhttp://gap-packages.github.io/io/doc/chap0.html[107X)    (in    particular
        Chapter 2) or the README-file of that package.[133X
  
  [30X    [33X[0;6YThe   installation   of  normaliz  is  possible  via  the  GAP-package
        NormalizInterface  ([7Xhttp://gap-packages.github.io/NormalizInterface//[107X)
        (at  least  0.9.6).  Just  access  the  folder  in  a  terminal and do
        [9X./build-normaliz.sh; ./configure; make[109X.[133X
  
  [30X    [33X[0;6YIf   you   want  to  use  4ti2,  please  make  sure  that  www.4ti2.de
        ([7Xhttp://www.4ti2.de[107X)  (Version  1.6.5 or newer) is properly installed.
        In  case  of an error-message "The executable 'zsolve' provided by the
        software 4ti2 was not found." after typing [9XLoadPackage("HeLP");[109X either
        the  software  is  not  properly installed or installed in a directory
        where  GAP  can  not  find  it,  i.e. a directory not contained in the
        path-variable. The content of this variable can typically be displayed
        by  typing [9Xecho $PATH[109X (Linux, Mac) [9Xecho %PATH%[109X (Windows) in a terminal
        or  a  command  prompt.  The  manual of 4ti2 contains several pages of
        information  on how to install the program. Note that the installation
        of  4ti2  requires  gcc  (g++) and gmp installed (which come with many
        Linux installations or can be installed using a package manager). Make
        sure  to  execute  all  four  commands  indicated  in  the 4ti2 manual
        (possibly without the [9X--prefix=[109X-part):[133X
  
        [33X[0;6Y[9X./configure --prefix=INSTALLATION-DIRECTORY[109X[133X
  
        [33X[0;6Y[9Xmake[109X[133X
  
        [33X[0;6Y[9Xmake check[109X[133X
  
        [33X[0;6Y[9Xmake install-exec[109X[133X
  
        [33X[0;6YDepending  on  the  settings  of  your  system  you  might  need  root
        privileges  (type  [9Xsudo[109X in front of every command) to unpack the files
        and  install  them.  To check whether the installation worked, you can
        enter  [9Xzsolve[109X in a terminal. In case one of the required programs (g++
        or  gmp)  was  not installed when running [9Xmake[109X for the first time, you
        might  need  to run [9Xmake clean[109X and the above commands afterwards again
        (several times) to compile 4ti2 successfully. If you already have 4ti2
        installed  in  a directory not contained in the path-variable and want
        to avoid a re-installation, in many cases the following helps:[133X
  
        [30X    [33X[0;12YStart  a  terminal  and  access  a  path written in your bash or
              system_bash. Typically [9Xusr/local/bin[109X should work.[133X
  
        [30X    [33X[0;12YRun  [9Xln  -s  /[PathToZsolve] zsolve[109X, where [9X[PathToZsolve][109X is the
              path  to the executable zsolve. This sets a symlink to the right
              place.  E.g.  [9Xln  -s /opt/4ti2/bin/zsolve zsolve[109X was used on the
              (Linux) computers in Stuttgart.[133X
  
  [30X    [33X[0;6YIn   case   you   use  4ti2,  we  also  recommend  to  install  lrslib
        ([7Xhttp://cgm.cs.mcgill.ca/~avis/C/lrs.html[107X), at least version 4.3 (note
        that  version 4.2 or older sometimes produces unwanted behavior). This
        software  provides  the 'redund' command, which can be switched on and
        off  within  HeLP,  but  which often leads to better performances (cf.
        [2XHeLP_UseRedund[102X  ([14X3.5-2[114X)). For installation see the User's Guide or the
        Readme-file  on the above mentioned homepage. Usually, after unpacking
        in  a  directory contained in the path-variable it should be enough to
        call[133X
  
        [33X[0;6Y[9Xmake all[109X[133X
  
        [33X[0;6Y(possibly as root) inside the lrslib-directory.[133X
  
  [30X    [33X[0;6YIf  this  does  not  help  to  get HeLP running, please feel more than
        welcome to contact one of the maintainers of the package.[133X
  
  
  [1X6.2 [33X[0;0YHow much 4ti2 and normaliz is really there?[133X[101X
  
  [33X[0;0YThe  reason, why the programs 4ti2 and normaliz are used in this package, is
  basically that they can solve systems of linear inequalities efficiently and
  there  exist good GAP-Interfaces for them. However there is only one line of
  code  where  a  function  is  called  which accesses 4ti2 and a few more for
  normaliz.  Thus  the effort of using another solver of inequalities would be
  not  so  big, if there is a GAP-Interface for it. If you are aware of such a
  solver  and would like to use it in this package, please contact the authors
  of this package. We will be happy to help.[133X
  
