Currently, vtd can run under

Linux
HP-UX 9, 10 and 11
SunOS

	I. Dependencies.
        ----------------

1) Fortran 90 compiler. 
   Supported compilers: gfortran 4.3.0 or newer and
                        Intel Fortran under Linux compiler 9.1 through 10.1.20
                        HP-UX Fortran compiler 2.4 or newer
                        Sun f90 compiler.

   NB: Intel Fortran under Linux compilers 10.1.21 through 11.1.037 have 
       a critical bug that generates code that produce WRONG RESULTS. 
       According to Intel representatives, this bug was fixed in 11.1.038.
       Although it has not been confirmed that this bug will affect any routine 
       from the VTD library, it is strongly suggested not to use affected 
       version of Fortran for Linux compiler.

2) C compiler;

3) petools. ( http://astrogeo.org/petools/ )

4) BLAS. (Basic Linear Algebra Software). It can be either a vendor supplied 
          library or ATLAS. ( http://math-atlas.sourceforge.net/ )


5) cfitsio (optionally). Refer to 
   http://heasarc.gsfc.nasa.gov/docs/software/fitsio/fitsio.html

6) gmake


	II. Compile and link.
        ---------------------


./configure
gmake
gmake install

  By default binary files are put in $HOME/bin and data files needed for
vtd are put in $HOME/share . Option --prefix= changes it. If configure 
does not find petools library, you need to specify the name of the 
library with full path explicitly using option --with-petools. 
Distribution kit contains also data files needed for computation of
path delay. By default these files are installed in $HOME/share/vtd
You can override these default with option --data.

Example:

./configure --prefix=/opt --with-petools=/opt --data=/data/vtd
            --with-cfitsio=/opt

  Complete list of configure options can be printed by ./configure --help

  The package VTD can be compiled with or without support of cfitsio
library for reading files in FITS-format. If the library VTD is compiled
without cfitsio support, it will not be able to compute and apply 
contribution caused by source structure.



	III. Post installation.
        -----------------------


  If you intend to use vtd you should apply definitions of environment
variables listed in file vtd_vars which was put in ${prefix}/bin 
directory, where ${prefix} is the name of the root directory which you have 
specified with option --with-prefix, or $HOME if you did not use this option.
Under tcsh or csh execute a command:

source ${prefix}/bin/vtd_vars

 It is a good idea to include this line in you shell startup command file.