Olds

Version 0.4.2 "Fitzebohnen", released in May 2023, comes with the following new features:

• If the environment variable CM_ECPP_TMPDIR is set, write checkpoint files during the second phase of ECPP while factoring class polynomials. This makes it possible to interrupt and restart the computation.

Version 0.4.1, "Fitzebohnen", released in January 2023, comes with the following new features:

• By choosing ECPP parameters differently, difficult prime numbers should be handled more gracefully. At least a reported difficult step now works reasonably fast. On the downside, certificates become a bit longer (by about 5% in the example), but I think this is set off by the smoother behaviour of the steps.
• The preliminary ECPP step of computing primorials takes a bit less memory in the MPI version.
• When ECPP certificates are output to a file, a second file in Primo format is created automatically.
• ECPP certificate creation uses class field towers unconditionally.
• An optional primality test is carried out before starting ECPP.
• Fix the ECPP code on 32 bit platforms.
• For larger numbers, the BPSW primality test of GMP is replaced by a Miller-Rabin test to base 2.
• If the environment variable CM_ECPP_TMPDIR is set, files that do not change between different invocations of ecpp or ecpp-mpi are stored in and read back from that directory.
• New command line options make it possible to compute only the first or only the second phase.
• Phase 2 results are stored in any order as they come in, which requires the file format to change. Checkpoint files ending in .cert2 from previous releases are not compatible.
• Add an optional dependency on FLINT to speed up root finding in the second ECPP phase.
• Decrease the trial division bound in ecpp-mpi, instead also distribute the numbers to be trial divided.
• Backport an improvement to the half gcd from PARI/GP git, which considerably speeds up the Cornacchia steps.

Version 0.4.0, "Fitzebohnen", released in May 2022, comes with the following new features:

• Increase the minimal version numbers of the dependencies, to MPFRCX 0.6.3 and PARI/GP 2.11.
• Add a decomposition of the class field into a tower of prime degree extensions following an algorithm developed with François Morain.
• Add an implementation of the fastECPP primality proving algorithm, complete with a version running over MPI.

Version 0.3.1 "Wurstebrei", released in September 2020, comes with the following new features:

• Increase the minimal version numbers of the dependencies, to MPFRCX 0.5 and PARI/GP 2.9.
• Bug fixes.
• Lots of internal changes.

Version 0.3, released in March 2016, comes with the following new features:

• Features
  • The baby-step giant-step algorithm of Enge-Hart-Johansson 2018 is used to compute the series of η, leading to a speed-up of up to a factor of 2 for this step of the algorithm.
  • Class polynomial computation for j and γ₂ is sped up by using a 2- or a 6-system, respectively, instead of a 1- or a 3-system. This makes it more likely that during the needed computation of η (τ/2) the conductor is not changed, so that a precomputed η value may be reused.
• Miscellanea
  • The license has been updated to GPLv3+, in line with the license of recent GMP, MPFR and MPC releases.

Version 0.2.1 "Blindhühnchen", released in March 2015, comes with the following new features:

• Features
  • Precisions beyond 300000 bits are now supported by an addition chain of variable length for the η-function.
• Dependencies
  • The minimal version number of MPFR has been increased to 3.0.0, that of MPC to 1.0.0 and that of Pari/GP to 2.7.0.

Version 0.2, released in February 2012, comes with the following new features:

• Features
  • new class invariants: multiple eta quotients with -imultieta
  • double eta quotients with both primes >100
  • new parameter choice for double eta quotients yielding smaller class polynomials
  • slightly lower height bounds for double eta quotients
• Bug fixes
  • printing of field and curve cardinality even without parameter -v
  • Weber polynomials work again (activated by -iweber)
  • class polynomials for D=-4 and D=-16 work (no curve is constructed)
• Dependencies
  • factorisation of class polynomials is done by pari instead of ntl

The initial release of version 0.1 "Apfelkraut" was made in November 2009.