Hi,
Various Sage users have reported on that parallelization of tensor field
computations does not work on macOS. The latest report, yesterday on
sagemanifolds.list:
https://sympa.obspm.fr/wws/arc/sagemanifolds.list/2018-08/msg00003.html
says that this example notebook
http://nbviewer.jupyter.org/github/sagemanifolds/SageManifolds/blob/master/Worksheets/v1.3/SM_Kerr.ipynb
fails with TypeError: Aborted (cf. the attached log), as soon as nproc is
set to something different than 1 in cell no. 4:
Parallelism().set(nproc=8)
Parallelization of computations on manifolds is implemented via the
multiprocessing module (using the @parallel decorator).
It works well on Linux and provides important speed-up.
On macOS, while it fails in interactive sessions, it seems to work within the
doctest framework (parallelization is doctested
in various files in src/sage/manifolds and src/sage/tensor/modules).
Apart from the manifold framework, does parallelization via the multiprocessing
module has been already shown to work on macOS?
Any hint on this issue would be appreciated (we don't have any macOS computer
in our group...)
Eric.
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sage-devel+unsubscr...@googlegroups.com.
To post to this group, send email to sage-devel@googlegroups.com.
Visit this group at https://groups.google.com/group/sage-devel.
For more options, visit https://groups.google.com/d/optout.
TypeError Traceback (most recent call last)
<ipython-input-34-b27f950e3fce> in <module>()
----> 1 nabla = g.connection() ; print(nabla)
/Applications/SageMath-8.3.app/Contents/Resources/sage/local/lib/python2.7/
site-packages/sage/manifolds/differentiable/metric.pyc in connection(self,
name, latex_name, init_coef)
771 self._connection = LeviCivitaConnection(self, name,
772
latex_name=latex_name,
--> 773
init_coef=init_coef)
774 return self._connection
775
/Applications/SageMath-8.3.app/Contents/Resources/sage/local/lib/python2.7/
site-packages/sage/manifolds/differentiable/levi_civita_connection.pyc in
__init__(self, metric, name, latex_name, init_coef)
229 # the domain (i.e. disregarding the subcharts)
230 for chart in self._domain.top_charts():
--> 231 self.coef(chart._frame)
232
233 def _repr_(self):
/Applications/SageMath-8.3.app/Contents/Resources/sage/local/lib/python2.7/
site-packages/sage/manifolds/differentiable/levi_civita_connection.pyc in
coef(self, frame)
525
526 # Computation and Assignation of values
--> 527 for ii, val in make_Connect(listParalInput):
528 for jj in val:
529 gam[jj[0],jj[1],jj[2],ii[0][1]] =
jj[3]
/Applications/SageMath-8.3.app/Contents/Resources/sage/local/lib/python2.7/
site-packages/sage/parallel/multiprocessing_sage.pyc in
parallel_iter(processes, f, inputs)
75 result = p.imap_unordered(call_pickled_function,
76 [(fp, t) for t in inputs])
---> 77 for res in result:
78 yield res
79 p.close()
/Applications/SageMath-8.3.app/Contents/Resources/sage/local/lib/python2.7/
multiprocessing/pool.pyc in next(self, timeout)
671 if success:
672 return value
--> 673 raise value
674
675 __next__ = next # XXX
TypeError: Aborted
