Wed 22 Mar 2023 : removed testnine.m, testnine.adb, testfivehom1.adb,
  and obsolete ts_rdisol.adb.

Fri 11 Jun 2021 : defined solver.gpr to build the test procedures.

Fri 4 Dec 2020 : moved mainwit into the new package main_intersection.
  Added the verbose level to the procedures in main_intersection.

Wed 2 Dec 2020 : renamed drivers_to_eqn_by_eqn_solvers into main_eqn_by_eqn_
  solvers and moved mainsolve into main_eqn_by_eqn_solvers as its main
  procedure.  Updated bablsolve.adb and removed the procedure mainsolve.
  Update ts_solver.adb for the renaming of the package.

Sun 22 Nov 2020 : moved mainhyp, mainhyp2, mainhyp4 into a new package
  main_hypersurface_witsets.

Sun 8 Nov 2020 : updated drivers_to_eqn_by_eqn_solvers.adb for the renaming
  of drivers_for_poly_continuation into main_poly_continuation.

Sat 14 Sep 2019 : added file_type and boolean as arguments to bablsolve.

Fri 6 Sep 2019 : added a file name as argument to bablsolve.

Thu 5 Sep 2019 : added verbose level to bablsolve.

Fri 30 Mar 2018 : equation_by_equation_solvers.adb changed because of
  improved interface in standard_solution_filters.

Mon 31 Jul 2017 : added the type conversions to the Silent_Root_Finder
  procedures in the *hypersurface_witdrivers.adb packages.
  Bug fix in *hypersurface_witdrivers.adb, swapped cases in conversions.

Sun 30 Jul 2017 : added calls to convertor functions in mainhyp.adb,
  mainhyp2.adb, and mainhyp4.adb so basic versions of phc -l, phc -l2,
  and phc -l4 work.  Adjusted declarations in *hypersurface_witdrivers*
  to make room for Laurent polynomials.  Added stub procedures to
  *hypersurface_witdrivers* to compute witness sets for Laurent polynomials.

Thu 27 Jul 2017 : made similar changes to mainhyp2.adb as done to mainhyp.adb;
  and did the similar changes also to mainhyp4.adb, to prepare to compute
  witness sets for hypersurfaces defined by Laurent polynomials, in double
  double and quad double precision.

Wed 26 Jul 2017 : started making of the witness set procedure in mainhyp.adb,
  for Laurent polynomials.

Tue 25 Jul 2017 : extended mainhyp, mainhyp2, mainhyp4, so phc -l, phc -l2,
  and phc -l4 accept Laurent polynomials on input.

Sat 22 Jul 2017 : updated equation_by_equation_solvers.adb for the splitting
  of the code in the package diagonal_homotopy_continuation.

Sun 15 Nov 2015 : updates in hypersurfaces_and_filters for double double and
  quad double arithmetic, new mainhyp2 and mainhyp4 for phc -l2 and -l4.

Wed 11 Nov 2015 : refactored code from standard_hypersurface_witsets_io into
  the new package standard_hypersurface_witdrivers, tested by ts_hypwit.
  This changed hypersurfaces_and_filters.adb.  Made dobldobl and quaddobl
  versions of the *hypersurface_witsets*, io and drivers, and extended
  the tests in ts_hypwit.adb.

Tue 10 Nov 2015 : renamed hypersurface_witness_sets and its _io into
  standard_hypersurface_witsets and its _io.

Thu 27 Jun 2013 : worked on the rest of the directory so all ts_ programs
  compile with the new 32-bit data types.

Wed 26 Jun 2013 : updated mainwit.adb for natural32.

Wed 20 Feb 2013 : added silent root finder to hypersurface_witness_sets_io
  tested by ts_hypwit.adb.

Thu 3 Aug 2011 : from equation_by_equation_solver.adb and
  hypersurfaces_and_filters.adb removed messages.

Wed 22 Jun 2001 : changed flow_tables.adb for a warning, updated
  hypersurfaces_and_filters.adb, equation_by_equation_solvers.adb, and
  drivers_to_eqn_by_eqn_solvers.adb.

Sun 12 Jun 2011 : added put_lines in equation_by_equation_solvers.adb to
  trace a bug.  Modified mainsolve.adb for the banner.

Thu 2 Jun 2011 : ts_solver.adb and ts_rdisol.adb needed string_splitters.
  Modified hypersurface_witness_sets_io.adb for warnings.

Sun 29 May 2011 : changed hypersurfaces_and_filters.adb and
  drivers_to_eqn_by_eqn_solvers.adb for warnings.

Fri 24 Sep 2010 : updated mainhyp.adb, mainwit.adb, bablsolve.adb, and
  mainsolve.adb because of the new string_splitters.

Thu 11 Oct 2007 : adjusted driver in hypersurface_witness_sets_io.adb
  and tester ts_hypwit.adb.

Wed 10 Oct 2007 : used code from ts_hypwit.adb to create the driver
  package hypersurface_witness_sets_io.

Wed 3 Oct 2007 : extended ts_hypwit.adb with output.

Wed 26 Sep 2007 : new ts_rdisol.adb to test new recursive solver.

Thu 14 Dec 2006 : because witness_points* became *sets*, mainwit.adb changed.
  Also drivers_to_eqn_by_eqn_solvers.adb changed.

Thu 24 Mar 2005 : fixed handling of output file in mainsolve, bug in 
  equation_by_equation_solver: after new random (b,v), update line!

Mon 21 Mar 2005 : the new standard_solution_splitters caused a change in
  the equation_by_equation_solvers.adb.

Sat 19 Mar 2005 : changing intrinsic_diagonal_homotopies into
  diagonal_homotopy_continuation changed equation_by_equation_solvers.adb.

Tue 8 Feb 2005 : new random b and v in equation_by_equation_solvers.adb.

Sun 16 Jan 2005 : changed drivers_to_eqn_by_eqn_solvers and
  equation_by_equation_solvers to allow for tuning and output options;
  also changed mainwit.adb to remain silent during tracking.

Mon 20 Dec 2004 : added mainhyp as driver to create a witness set for
  a hypersurface, given as argument to phc -l.

Sun 19 Dec 2004 : moved intrinsic_witness_sets_io to Samplers

Sat 18 Dec 2004 : added mainwit as driver to intersect witness sets.

Sun 21 Nov 2004 : made output of flow tables cleaner.

Thu 14 Oct 2004 : completed witness stones, also for G_solvers,
  after changing intrinsic_witness_sets_io, equation_by_equation_solvers,
  drivers_to_eqn_by_eqn_solvers.adb, and testnine.adb.

Wed 13 Oct 2004 : changed equation_by_equation_solvers.adb and
  drivers_to_eqn_by_eqn_solvers.adb for witness stones in G_solvers.

Tue 12 Oct 2004 : able to restart with witness stones in P_solvers,
  modified, intrinsic_witness_sets_io, equation_by_equations_solvers,
  drivers_to_eqn_by_eqn_solvers.adb, and testnine.adb.

Sun 10 Oct 2004 : invented "witness stone", new intrinsic_witness_sets_io
  and equation_by_equation_solvers, also drivers_to_eqn_by_eqn_solvers.

Thu 7 Oct 2004 : changed equation_by_equation_solvers, ts_solver,
  and intrinsic_witness_sets_io.adb to prepare for stepping stones.

Thu 22 Jul 2004 : created drivers_to_eqn_by_eqn_solvers for mainsolve
  and bablphc to be called by dispatch and mainphc respectively.

Tue 20 Jul 2004 : created intrinsic_witness_sets_io to write output of
  the solver to separate files.

Sat 17 Jul 2004 : added generic version to equation_by_equation_solvers,
  tested with ts_solver.adb and instantiated in testnine.adb,
  ready to move over to the public distribution PHCv2_3p.
