I have made up a distribution file for the modular symbol programs for
you.  You can find the file g0n.tar.gz in directory pub/cremona/progs
from the anonymous ftp server euclid.ex.ac.uk (144.173.8.2).  This
should be unzipped and untarred in a new directory.  There are about
144 files, arranged in three groups, and this certainly includes quite
a few which are not needed but it was quicker not to eliminate them.

The first group (procs) contains general-purpose arithmetic and linear
algebra, which make to a library file libprocs.a (all in the one
directory for simplicity).  The second group (curves) contain all the
elliptic curve programs (expect those relating to 2-descent, my mwrank
program), and make to a library libcurves.a.  I have included a few
useable programs here which should be made with "make curve_progs":
tate		 Tate's algorithm, reduction data
torsion		 Torsion subgroup
conductor	 Conductor (cut down version of tate)
twist		 Twists of a given curve (interactive)
allisog		 Isogenies of a given curve
findinf		 Search for rational points

Of these, allisog is not very robust without multiprecision floating
point arithmetic (see below).

Finally comes the group g0n (Gamma-zero-N) which makes the library
libg0n.a and the following programs:
tmanin	 Finds newforms at a given level N (you must have previously
run it at all levels M dividing N with 10 < M < N) and Hecke
eigenvalues.  Creates data files eigs/xnnn and newforms/ennn which are
neede by later stages.

h1first Use this after tmanin on any level to compute the
	corresponding modular elliptic curves.
h1bsd	Gives some data relating to BSD conjectures
h1curve Tabulates curves in a range, AFTER tmanin/h1first have been
	run on that range.
h1clist Ditto, different format
h1degphi Ditto, for tabulating degrees of modular parametrizations
hpcurve	 Alternative way of getting the curves after a tmanin run
	without running h1first (which takes longer) but gives less info.
h1bsdc  Gives fuller BSD data (after tmanin/h1first) including order
	of Sha in most cases.

I am not sure how much of this will interest you.  No doubt you will
have many questions...and if so, please be patient.

The tar file contains empty directories called eigs, newforms, intdata
which ARE needed.  After unpacking you should be able to just type
      make curve_progs
and/or
      make g0n_progs

and then run the programs.  If your gcc installation is much different
from mine (gcc version 2.7.2.3) you may have to tweak the makefile.  I
know there are some problems with gcc 2.8 but I have not installed it
yet.

If you examine the source you will find mentions to LIDIA which is a
large C++ library for computational number theory.  The code is
designed to work without this, and so you should not need it.  The
only program mentioned above which really needs it is allisog since
standard C double precision is not sufficient there.  Otherwise, you
will be using the libg++ package for multiprecision Integer arithmetic
and no multiprecision floating point.  The compatibility between the
two systems is handled in the file interface.h.