Writing Code for Sage

If there is something you would like to implement and make available in Sage, you have a wide range of options:

1. Implement it as Sage scripts.
2. Implement it as Python scripts that use the Sage library.
3. Implement it in C/C++ and make the result accessible to Sage using Cython.
4. Implement it using Cython.
5. Implement it using one or more of the following: Flint, FpLLL, GAP, GSL, IML, LinBox, M4RI, Matplotlib, Maxima, MWRank, ECLib, NetworkX, NTL, Numpy, PARI/GP, PolyBoRi, R, Scipy, Singular, Sympy or any of the other libraries included with Sage [1].
6. Or any combination of the above.

If you have Magma, Maple or Mathematica and do not mind restricting who can use your code, you could also implement parts of your program in one of these systems and make it available in Sage.

Flint, FpLLL, GAP, GSL, IML, LinBox, M4RI, Matplotlib, Maxima, MWRank, ECLib, NetworkX, NTL, Numpy, PARI/GP, PolyBoRi, R, Scipy, Singular, Sympy are all included with all distributions of Sage. GAP, Singular, and PARI are very mature, and each implements a great amount of functionality, though in different domains. GAP addresses group theory well, Singular attacks polynomial computation, and PARI contains sophisticated, optimized number theory algorithms. Notably absent from this triad is a good system for exact linear algebra (something Magma does extremely well), but this gap is being filled by code written for Sage or covered by specialized C/C++ libraries like LinBox, IML and M4RI.

Sage is not just about gathering together functionality. It is about providing a clear, systematic and consistent way to access a large number of algorithms, in a coherent framework that makes sense mathematically. In the design of Sage, the semantics of objects, the definitions, etc., are informed by how the corresponding objects are used in everyday mathematics.

This document was authored by William Stein, David Joyner, John Palmieri and others with the editorial help of Iftikhar Burhanuddin and Martin Albrecht.

[1]	See http://www.sagemath.org/links-components.html for a full list of packages shipped with every copy of Sage

Contents:

• Conventions for Coding in Sage
  • Python coding conventions
  • File and directory names
  • An example is worth a thousand words
  • Headings of Sage library code files
  • Documentation strings
    • Docstring markup with ReST and Sphinx
    • Automatic testing
    • Further conventions for automated testing of examples
  • Automated testing
    • Testing .py, .pyx and .sage files
    • Testing ReST documentation
  • Randomized testing
• Coding in Python for Sage
  • Design
  • Special Sage functions
    • LaTeX representation
    • Print representation
    • Matrix or vector from object
  • Sage preparsing
  • The Sage coercion model
  • Mutability
  • The __hash__ special method
  • Exceptions
  • Importing
  • Editing existing files
  • Creating a new directory
  • Using optional packages
• Coding in Other Languages
  • Cython
    • Special pragmas
    • Attaching or loading .spyx
  • Other languages
  • The PARI C library interface
  • GAP
  • Singular
  • Singular: Another approach
  • Creating a new pseudo-tty interface
• Parallel Testing the Sage Library
  • Testing a module
  • Troubleshooting
  • Parallel testing many modules
  • Parallel testing the whole Sage library
  • Beyond the Sage library
• The Sage Manuals
  • Editing the manuals
  • Setting hyperlink to modules, classes, methods, etc.
  • Adding a new file
  • Building the manuals
    • Document names
    • Output formats