markcbell / flipper Goto Github PK

I tried installing flipper in the docker image sagemath/sagemath-dev:8.7 via

$ sage -pip install flipper

It proceeds fine together with its dependencies (pandas, cypari). Though when importing I obtain

$ sage -python
Python 2.7.15 (default, Mar 24 2019, 03:41:40) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import flipper
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/sage/sage/local/lib/python2.7/site-packages/flipper/__init__.py", line 31, in <module>
    from flipper.census import census  # noqa: F401
  File "/home/sage/sage/local/lib/python2.7/site-packages/flipper/census.py", line 9, in <module>
    DATABASES = set(os.path.splitext(os.path.basename(path))[0] for path in os.listdir(DATABASE_DIRECTORY) if os.path.splitext(path)[1] == '.csv')
OSError: [Errno 2] No such file or directory: '/home/sage/sage/local/lib/python2.7/site-packages/flipper/censuses'

Currently, setup.py does not make it specific which versions of its requirements are needed. It would be great if we could be more specific there. In particular, this makes it easier to package flipper for distributions such as conda-forge.

Or maybe, any version that installs is actually good enough. Then it would be nice to mention it in setup.py.

The fact that pip install flipper triggers a cypari compilation is extremly annoying. cypari is very costly to install (time and space) and requires Cython as well as a C compiler. It is superseeded by cypari2 and moreover many distributions (Debian/Ubuntu, archlinux, Gentoo, conda, ...) does package cypari2 (which happens to also be a SageMath dependency).

See also sagemath/cypari2#19

With Python3 and the current version from PyPI

>>> import flipper
>>> S = flipper.load('S_2_1')
>>> h = S.mapping_class('acBD')
>>> h.flat_structure()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/sage/sage-py3-gcc/local/lib/python3.7/site-packages/flipper/kernel/encoding.py", line 792, in flat_structure
    edge_vectors[edges[0]] = flipper.kernel.Vector2(+stable_lamination(edges[0]), +unstable_lamination(edges[0]))
TypeError: bad operand type for unary +: 'RealAlgebraic'

Is there an easy way to convert between triangulations in Regina and triangulations in flipper? Both support importing and exporting isomorphism signatures but they don't seem immediately compatible. For example, regina.Triangulation3.fromIsoSig(flipper.load('S_1_2').triangulation.iso_sig())
results in
InvalidArgument: fromIsoSig(): incomplete signature
and
flipper.triangulation_from_iso_sig(regina.Triangulation3.fromIsoSig('cPcbbbiht').isoSig())
results in
ValueError: Signature must specify permutations for each triangle.