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# About

## SymPy Development Team

SymPy is a team project and it was developed by a lot of people.

Here is a list of contributors together with what they do, (and in some cases links to their wiki pages), where they describe in more details what they do and what they are interested in (some people didn’t want to be mentioned here, so see our repository history for a full list).

1. Ondřej Čertík: started the project in 2006, on Jan 4, 2011 passed the project leadership to Aaron Meurer
2. Fabian Pedregosa: everything, reviewing patches, releases, general advice (issues and mailinglist), GSoC 2009
3. Jurjen N.E. Bos: pretty printing and other patches
4. Mateusz Paprocki: GSoC 2007, concrete math module, integration module, new core integration, a lot of patches, general advice, new polynomial module, improvements to solvers, simplifications, patch review
5. Marc-Etienne M.Leveille: matrix patch
6. Brian Jorgensen: GSoC 2007, plotting module and related things, patches
7. Jason Gedge: GSoC 2007, geometry module, a lot of patches and fixes, new core integration
8. Robert Schwarz: GSoC 2007, polynomials module, patches
9. Pearu Peterson: new core, sympycore project, general advice (issues and mailinglist)
10. Fredrik Johansson: mpmath project and its integration in SymPy, number theory, combinatorial functions, products & summation, statistics, units, patches, documentation, general advice (issues and mailinglist)
11. Chris Wu: GSoC 2007, linear algebra module
12. Ulrich Hecht: pattern matching and other patches
13. Goutham Lakshminarayan: number theory functions
14. David Lawrence: GHOP, Mathematica parser, square root denesting
15. Jaroslaw Tworek: GHOP, sympify AST implementation, sqrt() refactoring, maxima parser and other patches
16. David Marek: GHOP, derivative evaluation patch, int(NumberSymbol) fix
17. Bernhard R. Link: documentation patch
18. Andrej Tokarčík: GHOP, python printer
19. Or Dvory: GHOP, documentation
20. Saroj Adhikari: bug fixes
21. Pauli Virtanen: bug fix
22. Robert Kern: bug fix, common subexpression elimination
23. James Aspnes: bug fixes
24. Nimish Telang: multivariate lambdas
25. Abderrahim Kitouni: pretty printing + complex expansion bug fixes
26. Pan Peng: ode solvers patch
27. Friedrich Hagedorn: many bug fixes, refactorings and new features added
28. Elrond der Elbenfuerst: pretty printing fix
29. Rizgar Mella: BBP formula for pi calculating algorithm
30. Felix Kaiser: documentation + whitespace testing patches
31. Roberto Nobrega: several pretty printing patches
32. David Roberts: latex printing patches
33. Sebastian Krämer: implemented lambdify/numpy/mpmath cooperation, bug fixes, refactoring, lambdifying of matrices, large printing refactoring and bugfixes
34. Vinzent Steinberg: docstring patches, a lot of bug fixes, nsolve (nonlinear equation systems solver), compiling functions to machine code, patches review
35. Riccardo Gori: improvements and speedups to matrices, many bug fixes
36. Case Van Horsen: implemented optional support for gmpy in mpmath
37. Štěpán Roučka: a lot of bug fixes all over SymPy (matrix, simplification, limits, series, ...)
38. Ali Raza Syed: pretty printing/isympy on windows fix
39. Stefano Maggiolo: many bug fixes, polishings and improvements
40. Robert Cimrman: matrix patches
41. Bastian Weber: latex printing patches
42. Sebastian Krause: match patches
43. Sebastian Kreft: latex printing patches, Dirac delta function, other fixes
44. Dan (coolg49964): documentation fixes
45. Alan Bromborsky: geometric algebra modules
46. Boris Timokhin: matrix fixes
47. Robert (average.programmer): initial piecewise function patch
48. Andy R. Terrel: piecewise function polishing and other patches
49. Hubert Tsang: LaTeX printing fixes
50. Konrad Meyer: policy patch
51. Henrik Johansson: matrix zero finder patch
52. Priit Laes: line integrals, cleanups in ODE, tests added
53. Freddie Witherden: trigonometric simplifications fixes, LaTeX printer improvements
54. Brian E. Granger: second quantization physics module
55. Andrew Straw: lambdify() improvements
56. Kaifeng Zhu: factorint() fix
57. Ted Horst: Basic.__call__() fix, pretty printing fix
58. Andrew Docherty: Fix to series
59. Akshay Srinivasan: printing fix, improvements to integration
60. Aaron Meurer: ODE solvers (GSoC 2009), The Risch Algorithm for integration (GSoC 2010), other fixes, project leader as of Jan 4, 2011
61. Barry Wardell: implement series as function, several tests added
62. Tomasz Buchert: ccode printing fixes, code quality concerning exceptions, documentation
63. Vinay Kumar: polygamma tests
64. Johann Cohen-Tanugi: commutative diff tests
65. Jochen Voss: a test for the @cachit decorator and several other fixes
66. Luke Peterson: improve solve() to handle Derivatives
67. Chris Smith: improvements to solvers, many bug fixes, documentation and test improvements
68. Thomas Sidoti: MathML printer improvements
69. Florian Mickler: reimplementation of convex_hull, several geometry module fixes
70. Nicolas Pourcelot: Infinity comparison fixes, latex fixes
71. Ben Goodrich: Matrix.jacobian() function improvements and fixes
72. Toon Verstraelen: code generation module, latex printing improvements
73. Ronan Lamy: test coverage script; limit, expansion and other fixes and improvements; cleanup
74. James Abbatiello: fixes tests on windows
75. Ryan Krauss: fixes could_extract_minus_sign(), latex fixes and improvements
76. Bill Flynn: substitution fixes
77. Kevin Goodsell: Fix to Integer/Rational
78. Jorn Baayen: improvements to piecewise functions and latex printing, bug fixes
79. Eh Tan: improve trigonometric simplification
80. Renato Coutinho: derivative improvements
81. Oscar Benjamin: latex printer fix, gcd bug fix
82. Øyvind Jensen: implemented coupled cluster expansion and wick theorem, improvements to assumptions, bugfixes
83. Julio Idichekop Filho: indentation fixes, docstring improvements
84. Łukasz Pankowski: fix matrix multiplication with numpy scalars
85. Chu-Ching Huang: fix 3d plotting example
86. Fernando Perez: symarray() implemented
87. Raffaele De Feo: fix non-commutative expansion
88. Christian Muise: fixes to logic module
89. Matt Curry: GSoC 2010 project (symbolic quantum mechanics)
90. Kazuo Thow: cleanup pretty printing tests
91. Christian Schubert: Fix to sympify()
92. Jezreel Ng: fix hyperbolic functions rewrite
93. James Pearson: Py3k related fixes
94. Matthew Brett: fixes to lambdify
95. Addison Cugini: GSoC 2010 project (quantum computing)
96. Nicholas J.S. Kinar: improved documentation about “Immutability of Expressions”
97. Harold Erbin: Geometry related work
98. Thomas Dixon: fix a limit bug
99. Cristóvão Sousa: implements _sage_ method for sign function.
100. Andre de Fortier Smit: doctests in matrices improved
101. Mark Dewing: Fixes to Integral/Sum, MathML work
102. Alexey U. Gudchenko: various work in matrices
103. Gary Kerr: fix examples, docs
104. Sherjil Ozair: fixes to SparseMatrix
105. Oleksandr Gituliar: fixes to Matrix
106. Sean Vig: Quantum improvement
107. Prafullkumar P. Tale: fixed plotting documentation
108. Vladimir Perić: fix some Python 3 issues
109. Tom Bachmann: fixes to Real
110. Yuri Karadzhov: improvements to hyperbolic identities
111. Vladimir Lagunov: improvements to the geometry module
112. Matthew Rocklin: stats, sets, matrix expressions
113. Saptarshi Mandal: Test for an integral
114. Gilbert Gede: Tests for solvers
115. Anatolii Koval: Infinite 1D box example
116. Tomo Lazovich: fixes to quantum operators
117. Pavel Fedotov: fix to is_number
118. Kibeom Kim: fixes to cse function and preorder_traversal
119. Gregory Ksionda: fixes to Integral instantiation
120. Tomáš Bambas: prettier printing of examples
121. Jeremias Yehdegho: fixes to the nthoery module
122. Jack McCaffery: fixes to asin and acos
123. Raymond Wong: Quantum work
124. Luca Weihs: improvements to the geometry module
125. Shai ‘Deshe’ Wyborski: fix to numeric evaluation of hypergeometric sums
126. Thomas Wiecki: Fix Sum.diff
127. Óscar Nájera: better Laguerre polynomial generator
128. Mario Pernici: faster algorithm for computing Groebner bases
129. Benjamin McDonald: Fix bug in geometry
130. Sam Magura: Improvements to Plot.saveimage
131. Stefan Krastanov: Make Pyglet an external dependency
132. Bradley Froehle: Fix shell command to generate modules in setup.py
133. Min Ragan-Kelley: Fix isympy to work with IPython 0.11
134. Nikhil Sarda: Fix to combinatorics/prufer
135. Emma Hogan: Fixes to the documentation
136. Jason Moore: Fixes to the mechanics module
137. Julien Rioux: Fix behavior of some deprecated methods
138. Roberto Colistete, Jr.: Add num_columns option to the pretty printer
139. Raoul Bourquin: Implement Euler numbers
140. Gert-Ludwig Ingold: Correct derivative of coth
141. Srinivas Vasudevan: Implementation of Catalan numbers
142. Miha Marolt: Add numpydoc extension to the Sphinx docs, fix ode_order
143. Tim Lahey: Rotation matrices
144. Luis Garcia: update examples in symarry
145. Matt Rajca: Code quality fixes
146. David Li: Documentation fixes
147. David Ju: Increase test coverage, fixes to KroneckerDelta
148. Alexandr Gudulin: Code quality fixes
149. Bilal Akhtar: isympy man page
150. Grzegorz Świrski: Fix to latex(), MacPorts portfile
151. Matt Habel: SymPy-wide pyflakes editing
152. Nikolay Lazarov: Translation of the tutorial to Bulgarian
153. Nichita Utiu: Add pretty printing to Product()
154. Tristan Hume: Fixes to test_lambdify.py
155. Imran Ahmed Manzoor: Fixes to the test runner
156. Steve Anton: pyflakes cleanup of various modules, documentation fixes for logic
157. Sam Sleight: Fixes to geometry documentation
158. tsmars15: Fixes to code quality
159. Chancellor Arkantos: Fixes to the logo
160. Stepan Simsa: Translation of the tutorial to Czech
161. Tobias Lenz: Unicode pretty printer for Sum
162. Siddhanathan Shanmugam: Documentation fixes for the Physics module
163. Tiffany Zhu: Improved the latex() docstring
164. Alexey Subach: Translation of the tutorial to Russian
165. Joan Creus: Improvements to the test runner
166. Geoffry Song: Improve code coverage
167. Puneeth Chaganti: Fix for the tutorial
168. Marcin Kostrzewa: SymPy Cheatsheet
169. Jim Zhang: Fixes to AUTHORS and .mailmap
170. Natalia Nawara: Fixes to Product()
171. vishal: Update the Czech tutorial translation to use a .po file
172. Shruti Mangipudi: added See Also documentation to Matrices
173. Davy Mao: Documentation
174. Swapnil Agarwal: added See Also documentation to ntheory, functions
175. Kendhia: Add XFAIL tests
176. jerryma1121: See Also documentation for geometry
177. Joachim Durchholz: corrected spacing issues identified by PyDev
178. Martin Povišer: fix problem with rationaltools
179. Siddhant Jain: See Also documentation for functions/special
180. Kevin Hunter: Improvements to the inequality classes
181. Michael Mayorov: Improvement to series
182. Nathan Alison: Additions to the stats module
183. Christian Bühler: remove use of set_main() in GA
184. Carsten Knoll: improvement to preview()
185. M R Bharath: modified use of int_tested, improvement to Permutation
186. Matthias Toews: File permissions
187. Sergiu Ivanov: Fixes to zoo, SymPyDeprecationWarning
188. Jorge E. Cardona: Cleanup in polys
189. Sanket Agarwal: Rewrite coverage_doctest.py script
190. Manoj Babu K.: Improve gamma function
191. Sai Nikhil: Fix to Heavyside with complex arguments
192. Aleksandar Makelov: Fixes regarding the dihedral group generator
193. Raphael Michel: German translation of the tutorial
194. Sachin Irukula: Changes to allow Dict sorting
195. Ashwini Oruganti: Changes to Pow printing
196. Andreas Kloeckner: Fix to cse()
197. Prateek Papriwal: improve summation documentation
198. Arpit Goyal: Improvements to Integral and Sum
199. Angadh Nanjangud: in physics.mechanics, added a function and tests for the parallel axis theorem
200. Comer Duncan: added dual, is_antisymmetric, and det_lu_decomposition to matrices.py
201. Jens H. Nielsen: added sets to modules listing, update IPython printing extension
202. Joseph Dougherty: modified whitespace cleaning to remove multiple newlines at eof
203. marshall2389: Spelling correction
204. Guru Devanla: Implemented quantum density operator
205. George Waksman: Implemented JavaScript code printer and MathML printer
206. Angus Griffith: Fix bug in rsolve
207. Timothy Reluga: Rewrite trigonometric functions as rationals
208. Brian Stephanik: Test for a bug in fcode
209. Ljubiša Moćić: Serbian translation of the tutorial
210. Piotr Korgul: Polish translation of the tutorial
211. Rom le Clair: French translation of the tutorial
212. Alexandr Popov: Fixes to Pauli algebra
213. Saurabh Jha: Work on Kauers algorithm
214. Tarun Gaba: Implemented some trigonometric integrals
215. Takafumi Arakaki: Add info target to the doc Makefile
216. Alexander Eberspächer: correct typo in aboutus.rst
217. Sachin Joglekar: Simplification of logic expressions to SOP and POS forms
218. Tyler Pirtle: Fix improperly formatted error message
219. Vasily Povalyaev: Fix latex(Min)
220. Colleen Lee: replace uses of fnan with S.NaN
221. Niklas Thörne: Fix links in the docs
222. Huijun Mai: Chinese translation of the tutorial
223. Marek Šuppa: Improvements to symbols, tests
224. Prasoon Shukla: Bug fixes
225. Sergey B Kirpichev: Bug fixes
226. Stefen Yin: Fixes to the mechanics module
227. Thomas Hisch: Improvements to the printing module
228. Matthew Hoff: Addition to quantum module
229. Madeleine Ball: Bug fix
230. Mary Clark: Improvements to the group theory module
231. Rishabh Dixit: Bug fixes
232. Manoj Kumar: Bug fix
233. Akshit Agarwal: improvements to range handling in symbols
234. CJ Carey: Fix for limits of factorials
235. Patrick Lacasse: Fix for Piecewise.subs
236. Ananya H: Bug fix
237. Tarang Patel: added test for issue 1640
238. Christopher Dembia: improvements to mecahanics documentation
239. Benjamin Fishbein: added rank method to Matrix
240. Sean Ge: made KroneckerDelta arguments canonically ordered
241. Ankit Agrawal: Statistical moments
242. Amit Jamadagni: qapply Rotation to spin states
243. Björn Dahlgren: Documentation fix
244. Christophe Saint-Jean: fixed and added metrics to galgebra
245. Demian Wassermann: fix to ccode printer for Piecewise
246. Khagesh Patel: Addition to matrix expressions
247. Stephen Loo: Update minimum gmpy2 version
248. Katja Sophie Hotz: use expansion in minpoly
249. Varun Joshi: Addition to functions
250. Chetna Gupta: Improvements to the Risch integration algorithm
251. Thilina Rathnayake: Fix to the matrices
252. Matthew Tadd: fix definition in units module
253. Alexander Hirzel: Updates to ODE docs
254. Randy Heydon: improve collinear point detection
255. Ramana Venkata: improvements to special functions

Up-to-date list in the order of the first contribution is given in the AUTHORS file.

You can find a brief history of SymPy in the README.

## Financial and Infrastructure Support

- Google: SymPy has received generous financial support from Google in various years through the Google Summer of Code program by providing stipends:
  - in 2007 for 5 students (GSoC 2007)
  - in 2008 for 1 student (GSoC 2008)
  - in 2009 for 5 students (GSoC 2009)
  - in 2010 for 5 students (GSoC 2010)
  - in 2011 for 9 students (GSoC 2011)
  - in 2012 for 6 students (GSoC 2012)
- Python Software Foundation (PSF) has hosted various GSoC students over the years:
  - 3 GSoC 2007 students (Brian, Robert and Jason)
  - 1 GSoC 2008 student (Fredrik)
  - 2 GSoC 2009 students (Freddie and Priit)
  - 4 GSoC 2010 students (Aaron, Christian, Matthew and Øyvind)
- Portland State University (PSU) has hosted following GSoC students:
  - 1 student (Chris) in 2007
  - 3 students (Aaron, Dale and Fabian) in 2009
  - 1 student (Addison) in 2010
- The Space Telescope Science Institute: STScI hosted 1 GSoC 2007 student (Mateusz)
- Several 13-17 year old pre-university students contributed as part of Google’s Code-In 2011. (GCI 2011)
- Simula Research Laboratory: supports Pearu Peterson work in SymPy/SymPy Core projects
- GitHub is providing us with development and collaboration tools

## License

Unless stated otherwise, all files in the SymPy project, SymPy’s webpage (and wiki), all images and all documentation including this User’s Guide are licensed using the new BSD license:

    Copyright (c) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 SymPy Development Team

    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:

      a. Redistributions of source code must retain the above copyright notice,
         this list of conditions and the following disclaimer.
      b. Redistributions in binary form must reproduce the above copyright
         notice, this list of conditions and the following disclaimer in the
         documentation and/or other materials provided with the distribution.
      c. Neither the name of SymPy nor the names of its contributors
         may be used to endorse or promote products derived from this software
         without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
    ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
    DAMAGE.

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