Sage: Open Source Mathematical Software

       "Creating a Viable Open Source Alternative to
          Magma, Maple, Mathematica, and MATLAB"

    Copyright (C) 2005-2012 William Stein and the Sage Development Team

        http://www.sagemath.org

    Over 200 people have contributed code to Sage. Please see the
    following web page for a list:

        http://www.sagemath.org/development-map.html

    In many cases, documentation for modules and functions list the
    authors.


GETTING STARTED
---------------

This README.txt contains build instructions for Sage. If you downloaded
a binary, you do not need to do anything; just execute:

    ./sage

from the command line. If you downloaded the sources, please read below
on how to build Sage and work around common issues.

If you have questions or encounter problems, please do not hesitate
to email the sage-support mailing list:

    http://groups.google.com/group/sage-support


SUPPORTED PLATFORMS
-------------------

Sage fully supports several Linux distributions, recent versions of
Mac OS X, as well as a number of Solaris and OpenSolaris releases.

There should be no serious bugs in an officially released version of
Sage on any of the fully supported platforms, but any major issues with
a particular release will be documented on an errata page:

    http://wiki.sagemath.org/errata

Ports are in progress to some other, less common platforms. The list of
supported platforms and their current statuses are given at the
following web page:

    http://wiki.sagemath.org/SupportedPlatforms

If you are interested in helping port Sage to a new platform, please let
us know at the sage-devel mailing list:

    http://groups.google.com/group/sage-devel


QUICK INSTRUCTIONS TO BUILD FROM SOURCE
---------------------------------------

The following steps briefly outline the process of building Sage from
source. More detailed instructions, including how to build faster on
multicore machines are contained later in this README and in the
Installation Guide:

    http://www.sagemath.org/doc/installation

1. Make sure you have the dependencies and 3 GB of free disk space.

   Linux: gcc, make, m4, perl, ranlib, and tar.
   (install these using your package manager)
   On recent Debian or Ubuntu systems (in particular Ubuntu 12.04
   "Precise"), you need the dpkg-dev package.

   OS X: Xcode. Make sure you have installed the most recent version
   of Xcode. For pre-Lion versions of OS X, you can download Xcode
   from http://developer.apple.com/downloads/. For OS X Lion, you can
   install it using the App Store. With Xcode 4.3 or later, you need
   to install the "Command Line Tools": from the File menu, choose
   "Preferences", then the "Downloads" tab, and then "Install" the
   Command Line Tools.

   Other platforms: See detailed instructions below.

2. Extract the tarball:

       tar xvf sage-*.tar

3. cd into the Sage directory and type make:

       cd sage-*/
       make

   That's it! Everything is automatic and non-interactive. The build
   should work fine on all fully supported platforms. If it does not, we
   want to know!


ENVIRONMENT VARIABLES
---------------------

There are a lot of environment variables which control the install
process of Sage, see:

    http://sagemath.org/doc/installation/source.html#environment-variables


SELINUX
--------

On Linux, if you get this error message:

    Error: cannot restore segment prot after reloc: Permission denied

the problem is probably related to SELinux. See the following URL for
further information:

    http://www.exelisvis.com/Support/HelpArticleDetail/ArticleId/3092.aspx


IMPLEMENTATION
--------------

Sage has significant components written in the following languages:
C/C++, Python, Cython, Lisp, and Fortran. Lisp (ECL), Python, and Cython
are built as part of Sage and a GNU Fortran (gfortran) binary is
included (OS X only), so you do not need them in order to build Sage.


MORE DETAILED INSTRUCTIONS TO BUILD FROM SOURCE
-----------------------------------------------

1. Make sure you have about 3 GB of free disk space.

2. Install build dependencies.

   Linux: See quick instructions above.

   OS X: Make sure you have XCode version >= 2.4, i.e. "gcc -v" should
   output build >= 5363. If you don't, go to:

       http://developer.apple.com/

   sign up, and download the free XCode package. Only OS X >= 10.4 is
   supported.

   Solaris and OpenSolaris: Building Sage on these platforms is more
   tricky than on Linux or OS X. For details on how to build Sage on
   these platforms, see:

       http://wiki.sagemath.org/solaris

   Windows: Not supported. A solution is to download and install
   VirtualBox, install Linux into it, etc.

   NOTE: On some operating systems, it might be necessary to install
   gas/as, gld/ld, gnm/nm. On most platforms, these are automatically
   installed when you install the programs listed above.

3. Extract the Sage source tarball and cd into a directory with no
   spaces in it. If you have a machine with 4 processors, say, type
   the following to configure the build script to perform a parallel
   compilation of Sage using 4 jobs:

       export MAKE="make -j4"

   (With 4 processors, you might also consider "-j5" or "-j6" --
   building with more jobs than CPU cores can speed things up.)
   You might in addition pass a "-l" flag to "make": this
   sets a load limit, so for example if you execute

       export MAKE="make -j4 -l5.5"

   then "make" won't start more than one job at a time if the system
   load average is above 5.5.  See
   http://www.gnu.org/software/make/manual/make.html#Options-Summary
   and http://www.gnu.org/software/make/manual/make.html#Parallel.

   If you want to run the test suite for each individual spkg as it is
   installed, type:

       export SAGE_CHECK="yes"

   before starting the Sage build. This will run each test suite and
   will raise an error if any failures occur. Python's test suite has
   been disabled by default, because it causes failures on most
   systems. To renable the Python testsuite, set the environment
   variable SAGE_CHECK_PACKAGES to "python".

   To start the build, type:

       make

4. Wait about 1 hour to 14 days, depending on your computer (it took
   about 2 weeks to build Sage on the T-Mobile G1 Android cell phone).

5. Type "./sage" to try it out.

6. OPTIONAL: Start Sage and run the command

       install_scripts("/usr/local/bin/")   # change /usr/local/bin/

   Type "install_scripts?" in Sage for more details about what this
   command does.

7. OPTIONAL: Type "make test" to test all examples in the documentation
   (over 93,000 lines of input!) -- this takes from 30 minutes to
   several hours. Don't get too disturbed if there are 2 to 3 failures,
   but always feel free to email the section of test.log that contains
   errors to the sage-support mailing list. If there are numerous
   failures, there was a serious problem with your build.

8. OPTIONAL: If you want to (try to) build the documentation, run:

       sage --docbuild --help

   for instructions. The HTML version of the documentation is built
   during the compilation process of Sage and resides in the directory:

       $SAGE_ROOT/devel/sage/doc/output/html/

   LaTeX is required to build the PDF version of the documentation.

9. OPTIONAL: It is highly recommended that you install the optional GAP
   database by typing:

       ./sage --optional

   then installing (with "./sage -i") the package whose name begins with
   database_gap. This will download the package from
   sage.math.washington.edu and install it. While you're at it, you
   might install other databases of interest to you.

10. OPTIONAL: It is recommended that you have both LaTeX and the
    ImageMagick tools (e.g. the "convert" command) installed since some
    plotting functionality benefits from it.


PROBLEMS
--------

If you have problems building Sage, check the Sage Installation Guide,
and also note the following.  Each separate component of Sage is
contained in an spkg; these are stored in spkg/standard/.  As each one
is built, a build log is stored in spkg/logs/, so you can browse these
to find error messages.  If an spkg fails to build, the whole build
process will stop soon after, so check the most recent log files
first, or run

   grep -li "^Error" spkg/logs/*

from the top-level Sage directory to find log files with error
messages in them.  Send (a small part of) the relevant log file to the
sage-devel mailing list, making sure to include at least some of the
error messages; probably someone there will have some helpful
suggestions.


SUPPORTED COMPILERS
-------------------

Sage includes a GCC (GNU Compiler Collection) package. In order to
build Sage, you need a C compiler which can build GCC and its
prerequisites. gcc version 4.0.1 or later should probably work. On
Solaris or OpenSolaris, building with the Sun compiler should also work.

The GCC package in Sage is not always installed. It is determined
automatically whether it needs to be installed. You can override this
by setting the environment variable SAGE_INSTALL_GCC=yes (to force
installation of GCC) or SAGE_INSTALL_GCC=no (to disable installation of
GCC). If you don't want to install GCC, you need to have recent
versions of gcc, g++ and gfortran; moreover, the versions must be equal.

There are some known problems with old assemblers, in particular when
building the ECM package. You should ensure that your assembler
understands all instructions for your processor. On Linux, this means
you need a recent version of binutils; on OS X you need a recent version
of XCode.


RELOCATION
----------

You *should* be able to move the sage-x.y.z/ directory anywhere you
want. If you copy the sage script or make a symbolic link to it, you
should modify the script to reflect this (as instructed at the top of
the script). It is best if the path to Sage does not have any spaces in
it.

For a system-wide installation, as root you can move the sage-x.y.z/
directory to a system-wide directory. Afterwards, you need to start up
Sage as root at least once prior to using the system-wide Sage as a
normal user. See the Installation Guide for further information on
performing a system-wide installation:

    http://www.sagemath.org/doc/installation/source.html#installation-in-a-multiuser-environment

If you find anything that doesn't work correctly after you moved the
directory, please email the sage-support mailing list.


REDISTRIBUTION
--------------

Your local Sage install is almost exactly the same as any "developer"
install. You can make changes to documentation, source, etc., and very
easily package the complete results up for redistribution just like we
do.

1. To make your own source tarball (sage-x.y.z.tar) of Sage, type:

       sage --sdist x.y.z

   where the version is whatever you want.

2. To make a binary distribution with your currently installed packages,
   type:

       sage --bdist x.y.z

3. To make a binary that will run on the widest range of target
   machines, set the SAGE_FAT_BINARY environment variable to "yes"
   before building Sage:

       export SAGE_FAT_BINARY="yes"
       make
       ./sage --bdist x.y.z-fat

In all cases, the result is placed in the directory "$SAGE_ROOT/dist/".


CHANGES TO INCLUDED SOFTWARE
----------------------------

All software included with Sage is copyrighted by the respective authors
and released under an open source license that is "GPL version 3 or
later" compatible. See the file COPYING.txt for more details.

Almost every spkg in $SAGE_ROOT/spkg/standard/ is a bzip2-compressed
tarball (currently, the only exception is the bzip2 spkg itself, which
is gzip-compressed). You can extract it with:

    tar xvf name-*.spkg

Inside the spkg, there is a file SPKG.txt that details all changes made
to the given package for inclusion with Sage. The inclusion of such a
file detailing changes is specifically required by some of the packages
included with Sage (e.g. for GAP).