Monday, March 31, 2008

Sage 2.11 is out!

Sage 2.11 has been released. In total 31 people did contribute patches for this release. Due to spring break and the easter holidays things moved a little slower than I had anticipated. But in the end it looks like we put together a pretty decent release. Binaries are available by now.

The high level changes in detail are:

  • ATLAS: Michael Abshoff and Burcin Erocal upgraded ATLAS to the 3.8.1 release. In addition tuning info for 32 bit Prescott CPUs as well as Powerbook G4s under Linux was added.
  • zn_poly: David Harvey's zn_poly library is now a standard package for Sage. zn_poly is a new C library for polynomial arithmetic in (Z/nZ)[x] where 3≤n≤ULONG_MAX (i.e. any machine-word-sized modulus). The main benefit is speed. The library is used so far only to compute the zeta function for hyperelliptic curves.
  • Small roots method for polynomials mod N (N composite): Martin Albrecht implemented Coppersmith's method for finding small roots of univariate polynomials modulo N where N is composite.
  • Generic Multivariate Polynomial Arithmetic: Joel Mohler improved the efficiency of the generic multivariate polynomial arithmetic in Sage by roughly a factor of ten.
  • k-Schur Functions and Non-symmetric Macdonald Polynomials: Mike Hansen: k-Schur functions s^(k)_\lambda are a relatively new family of symmetric functions which play a role in Z[h1,...,hk] as the Schur functions s_\lambda do in \Lambda. The k-Schur functions, amongst other things, provide a natural basis for the quantum cohomology of the Grassmannian. The k-Schur functions can be used like any other symmetric functions and are created with kSchurFunctions. Non-symmetric Macdonald polynomials in type A can now be accessed in Sage. The polynomials are computed from the main theorem in "A Combinatorial Formula for the Non-symmetric Macdonald Polynomials" by Haglun, Haiman, and Loehr.
  • Marshall Hampton did upgrade gfan as well as the optional phcpack spkgs and their interfaces. He also increased doctest coverage to 100% for both interfaces.
  • Improved capabilities for solving matrix equations: William Stein implemented code so that one can now solve matrix equations AX=B and XA=B whenever a solution exists. In particular, solving linear equations now works even if A is singular or nonsquare.
  • Generators for congruence subgroups: Robert Miller implemented an algorithm for very quickly computing generators for congruence subgroups \Gamma_0(N), \Gamma_1(N), and \Gamma_H(N).
  • Various other people fixed a number of bugs and did improve other bits of Sage.
Next up is the 3.0 release. We are shooting for a two week release cycle, but we will see how things go :)



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