Sage: Open Source Mathematical Software

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

Copyright (C) 2005-2020 The Sage Development Team

https://www.sagemath.org

The Sage Library is GPLv2+, and included packages have compatible OSS licenses. Over 400 people have contributed code to Sage. In many cases, documentation for modules and functions list the authors.

Getting Started

If you downloaded a binary (i.e. a version of SageMath prepared for a specific operating system), Sage is ready to start -- just open a terminal in the directory where you extracted the binary archive and type:

./sage

(Note that the first run will take more time, as Sage needs to get itself ready.)

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 or ask on ask.sagemath.org.

Supported Platforms

Sage fully supports all major Linux distributions, recent versions of macOS, and Windows (using Cygwin, Windows Subsystem for Linux, or using virtualization).

We highly appreciate contributions to Sage that fix portability bugs and help port Sage to new platforms; let us know at the sage-devel mailing list.

Docker Images

You can also have a look at our Docker images to run Sage. To use these images install Docker and follow the instructions on our Docker Hub page.

[Windows] Preparing the Platform

The 64-bit version of Cygwin, also known as Cygwin64, is the current target for Sage support on Windows.

Download cygwin64 (do not get the 32-bit version; it is not supported by Sage).
Run the setup-x86_64.exe graphical installer. Pick the default options in most cases. At the package selection screen, use the search bar to find and select at least the following packages: bzip2, coreutils, curl, gawk, gzip, tar, wget, git.
Start the Cygwin terminal and ensure you get a working bash prompt.
Make sure the path of your Cygwin home directory does not contain space characters.

By default, your username in Cygwin is the same as your username in Windows. This might contain spaces and other traditionally non-UNIX-friendly characters, e.g., if it is your full name. You can check this as follows:
```
 $ whoami
 Erik M. Bray
```
This means your default home directory on Cygwin contains this username verbatim; in the above example, /home/Erik M. Bray. It will save some potential trouble if you change your Cygwin home directory to something not containing any non-alphanumeric characters, for example, /home/embray. The easiest way to do this is to first create the home directory you want to use instead, then create an /etc/passwd file specifying that directory as your home, as follows:
```
 $ whocanibe=embray
 $ mkdir /home/$whocanibe
 $ mkpasswd.exe -l -u "$(whoami)" | sed -r 's,/home/[^:]+,/home/'$whocanibe, > /etc/passwd
```
After this, close all Cygwin terminals (ensure nothing in C:\cygwin64 is running), then start a new Cygwin terminal and your home directory should have moved.

There are other ways to do this, but the above seems to be the simplest that's still supported.

Install the package manager apt-cyg:

 $ curl -OL https://rawgit.com/transcode-open/apt-cyg/master/apt-cyg
 $ install apt-cyg /usr/local/bin
 $ rm -f apt-cyg

An alternative to Cygwin is to use Windows Subsystem for Linux, which allows you to install a standard Linux distribution such as Ubuntu within your Windows. Then all instructions for installation in Linux apply.

As another alternative, you can also run Linux on Windows using Docker (see above) or other virtualization solutions such as the Sage virtual appliance.

[macOS] Preparing the Platform

Make sure you have installed the most current version of Xcode supported on your version of macOS. If you don't, go to https://developer.apple.com/, sign up, and download the free Xcode package.

You also need to install the "command line tools": After installing Xcode, run xcode-select --install from a terminal window; then click "Install" in the pop-up window. (When using Mountain Lion or earlier, you need to install the command line tools from Xcode: run Xcode; then from the File menu, choose "Preferences", then the "Downloads" tab, and then "Install" the Command Line Tools.)

Optionally, you can consider installing Homebrew ("the missing package manager for macOS") from https://brew.sh/, which can provide libraries such gfortran, gmp, etc.

Instructions to Build from Source

Like many other software packages, Sage is built from source using ./configure, followed by make. However, we strongly recommend to read the following step-by-step instructions for building Sage.

The instructions cover all of Linux, macOS, and Cygwin.

More detailed instructions are contained in the Installation Guide.

Decide on the source/build directory (SAGE_ROOT):
- For example, you could use SAGE_ROOT=~/sage/sage-x.y, which we will use as the running example below, where x.y is the current Sage version.
- You need at least 6 GB of free disk space.
- The path name must contain no spaces.
- After starting the build, you cannot move the source/build directory without breaking things.
- [Cygwin] Avoid building in home directories of Windows domain users or in paths with capital letters.
Download/unpack the sources.
- After downloading the source tarball sage-x.y.tar.gz into ~/sage/:
```
  $ cd ~/sage/
  $ tar zxvf sage-x.y.tar.gz
```
  This will create the subdirectory sage-x.y.
- [Git] Alternatively, clone the Sage git repository:
```
  $ git clone --branch master git://trac.sagemath.org/sage.git
```
  This will create the subdirectory sage.
- [Windows] The Sage source tree contains symbolic links, and the build will not work if Windows line endings rather than UNIX line endings are used.
  
  Therefore it is crucial that you unpack the source tree from the Cygwin (or WSL) bash using the Cygwin (or WSL) tar utility and not using other Windows tools (including mingw). Likewise, when using git, it is crucial that you use the Cygwin (or WSL) version of git, and that you configure it as follows first:
```
  $ git config --global core.autocrlf false
  $ git config --global core.symlinks true
```
cd into the source/build directory:
```
 $ cd sage*/
```
Optionally, decide on the installation prefix (SAGE_LOCAL):
- Traditionally, and by default, Sage is installed into the subdirectory hierarchy rooted at SAGE_ROOT/local.
- This can be changed using ./configure --prefix=SAGE_LOCAL, where SAGE_LOCAL is the desired installation prefix, which must be writable by the user. (See the installation manual for options if you want to install into shared locations such as /usr/local/. Do not attempt to build Sage as root.)
[Git] If you cloned the Sage repository using git, bootstrap the source tree using:
```
 $ make configure
```
[Linux, Cygwin] Install the required minimal build prerequisites.
- Compilers: gcc, gfortran, g++ (a matching set of these three will avoid the compilation of Sage-specific compilers - unless they are too old). See the Installation Manual for a discussion of suitable compilers.
- Build tools: GNU make, GNU m4, perl (including ExtUtils::MakeMaker), ranlib, git, tar, bc
- Any version of python (full installation including urllib), but ideally version 3.7.x, which will avoid having to build Sage's own copy of Python 3.
We have collected lists of system packages that provide these build prerequisites. See build/pkgs/arch.txt, cygwin.txt, debian.txt (also for Ubuntu, Linux Mint, etc.), fedora.txt (also for Red Hat, CentOS), and slackware.txt.
Optional, but highly recommended: Make sure your system has an SSL library and its development files installed.

Like Python, on which it is based, Sage uses the OpenSSL library for added performance if made available by the operating system. It has been shown that Sage can be successfully built against other SSL libraries, with some of its features disabled.
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.
Optionally, review the configuration options, which includes many optional packages:
```
 ./configure --help
```
Optional, but highly recommended: Set some environment variables to customize the build.

For example, the MAKE environment variable controls whether to run several jobs in parallel. On a machine with 4 processors, say, typing export MAKE="make -j4" will configure the build script to perform a parallel compilation of Sage using 4 jobs. On some powerful machines, you might even consider -j16, as building with more jobs than CPU cores can speed things up further.

If you want to run the test suite for each individual Sage package as it gets installed, type export SAGE_CHECK="yes". This will run each test suite, raising an error if any failure occurs. If set to warn, then only a warning is printed in this case.

To reduce the terminal output during the build, type export V=0. (V stands for "verbosity".)

For an in-depth discussion of more environment variables for building Sage, see the installation guide.

Type ./configure, followed by any options that you wish to use. For example, to build a Python2-based Sage (which was the default before Sage 9.0), use ./configure --with-python=2.

At the end of a successful ./configure run, you may see messages recommending to install extra system packages using your package manager.

For a large list of Sage packages, Sage is able to detect whether an installed system package is suitable for use with Sage; in that case, Sage will not build another copy from source.

Sometimes, the messages will recommend to install packages that are already installed on your system. See the earlier configure messages or the file config.log for explanation. Also, the messages may recommend to install packages that are actually not available; only the most recent releases of your distribution will have all of these recommended packages.

Optional: If you choose to install the additional system packages, a re-run of ./configure will test whether the versions installed are usable for Sage; if they are, this will reduce the compilation time and disk space needed by Sage. The usage of packages may be adjusted by ./configure parameters (check again the output of ./configure --help).
Type make. That's it! Everything is automatic and non-interactive; but it will take a few hours (on a recent computer).

The build should work fine on all fully supported platforms. If it does not, we want to know!

Type ./sage to try it out.
Optional: Type make ptestlong to test all examples in the documentation (over 200,000 lines of input!) -- this takes from 10 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 logs/ptestlong.log that contains errors to the sage-support mailing list. If there are numerous failures, there was a serious problem with your build.
The HTML version of the documentation is built during the compilation process of Sage and resides in the directory local/share/doc/sage/html/.
Optional: If you want to build the PDF version of the documentation, run make doc-pdf (this requires LaTeX to be installed).
Optional: You might install optional packages of interest to you: type ./sage --optional to get a list.

Troubleshooting

If you have problems building Sage, check the Sage Installation Guide, as well as the version-specific Sage Installation FAQ in the Sage Release Tour corresponding to the version that you are installing.

Please do not hesitate to ask for help in the SageMath forum or the sage-support mailing list. The Troubleshooting section in the Sage Installation Guide provides instructions on what information to provide so that we can provide help more effectively.

Contributing to Sage

If you'd like to contribute to Sage, we strongly recommend that you read the Developer's Guide.

Sage has significant components written in the following languages: C/C++, Python, Cython, Common Lisp, Fortran, and a bit of Perl.

Directory Layout

Simplified directory layout (only essential files/directories):

SAGE_ROOT                 Root directory (sage-x.y.z in Sage tarball)
├── build
│   └── pkgs              Every package is a subdirectory here
│       ├── atlas
│       …
│       └── zn_poly
├── COPYING.txt           Copyright information
├── local                 Compiled packages are installed here
│   ├── bin               Executables
│   ├── include           C/C++ headers
│   ├── lib               Shared libraries
│   ├── share             Databases, architecture-independent data, docs
│       └── doc           Viewable docs of Sage and of some components
│   └── var
│       ├── sage          List of installed packages
│       └── tmp           Temporary files when building Sage
├── logs
│   ├── dochtml.log       Log of the documentation build
│   ├── install.log       Full install log
│   └── pkgs              Build logs of individual packages
│       ├── atlas-3.10.1.p7.log
│       …
│       └── zn_poly-0.9.p11.log
├── m4                    M4 macros for configure
│   └── *.m4
├── Makefile              Running "make" uses this file
├── README.md             This file
├── sage                  Script to start Sage
├── src                   All of Sage source (not third-party packages)
│   ├── bin               Scripts that Sage uses internally
│   ├── doc               Sage documentation sources
│   └── sage              The Sage library source code
├── upstream              Source tarballs of packages
│   ├── atlas-3.10.1.tar.bz2
│   …
│   └── zn_poly-0.9.tar.bz2
└── VERSION.txt

For more details see our Developer's Guide.

Build System

This is a brief summary of the Sage software distribution's build system. There are two components to the full Sage system--the Sage Python library and its associated user interfaces, and the larger software distribution of Sage's main dependencies (for those dependencies not supplied by the user's system).

Sage's Python library is built and installed using a setup.py script as is standard for Python packages (Sage's setup.py is non-trivial, but not unusual).

Most of the rest of the build system is concerned with building all of Sage's dependencies in the correct order in relation to each other. The dependencies included by Sage are referred to as SPKGs (i.e. "Sage Packages") and are listed under build/pkgs.

The main entrypoint to Sage's build system is the top-level Makefile at the root of the source tree. Unlike most normal projects that use autoconf (Sage does as well, as described below), this Makefile is not generated. Instead, it contains a few high-level targets and targets related to bootstrapping the system. Nonetheless, we still run make <target> from the root of the source tree--targets not explicitly defined in the top-level Makefile are passed through to another Makefile under build/make/Makefile.

The latter build/make/Makefile is generated by an autoconf-generated configure script, using the template in build/make/Makefile.in. This includes rules for building the Sage library itself (make sagelib), and for building and installing each of Sage's dependencies (e.g. make python2).

The configure script itself, if it is not already built, can be generated by running the bootstrap script (the latter requires GNU autotools being installed). The top-level Makefile also takes care of this automatically.

To summarize, running a command like make python3 at the top-level of the source tree goes something like this:

make python3
run ./bootstrap if configure needs updating
run ./configure with any previously configured options if build/make/Makefile needs updating
cd into build/make and run the install script--this is little more than a front-end to running make -f build/make/Makefile python3, which sets some necessary environment variables and logs some information
build/make/Makefile contains the actual rule for building python3; this includes building all of python3's dependencies first (and their dependencies, recursively); the actual package installation is performed with the sage-spkg program

Relocation

It is not supported to move the SAGE_ROOT or SAGE_LOCAL directory after starting the build. If you do move the directories, you will have to rebuilt Sage again from scratch.

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 important that the path to Sage does not have any spaces and non-ASCII characters in it.

For a system-wide installation, you have to build Sage as a "normal" user and then as root you can change permissions. 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.

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.

To make a binary distribution with your currently installed packages, visit sagemath/binary-pkg.
(Obsolete, probably broken) To make your own source tarball of Sage, type:
```
sage --sdist
```
The result is placed in the directory 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 COPYING.txt for more details.

Sources are in unmodified (as far as possible) tarballs in the upstream/ directory. The remaining description, version information, patches, and build scripts are in the accompanying build/pkgs/<packagename> directory. This directory is part of the Sage git repository.

GloriaYY/sage