cygwin: various heegner_index errors involving interval arithmetic on cygwin

[williamstein]

sage -t  "devel/sage/sage/schemes/elliptic_curves/heegner.py"
**********************************************************************
File "/home/wstein/sage-4.4.3/devel/sage/sage/schemes/elliptic_curves/heegner.py", line 6380:
    sage: E.heegner_index(-7)
Expected:
    1.00000?
Got:
    1
**********************************************************************
File "/home/wstein/sage-4.4.3/devel/sage/sage/schemes/elliptic_curves/heegner.py", line 6410:
    sage: I = E.heegner_index(-8); I
Expected:
    1.50000?
Got:
    1
**********************************************************************
File "/home/wstein/sage-4.4.3/devel/sage/sage/schemes/elliptic_curves/heegner.py", line 6412:
    sage: 2*I
Expected:
    3.0000?
Got:
    2
**********************************************************************
File "/home/wstein/sage-4.4.3/devel/sage/sage/schemes/elliptic_curves/heegner.py", line 6546:
    sage: E.heegner_index_bound()
Expected:
    ([2], -7)
Got:
    ([], -7)
**********************************************************************
2 items had failures:
   3 of  15 in __main__.example_229
   1 of   4 in __main__.example_231
***Test Failed*** 4 failures.
For whitespace errors, see the file /home/wstein/.sage//tmp/.doctest_heegner.py

CC: @kcrisman @dimpase

Component: porting: Cygwin

Reviewer: Jean-Pierre Flori, Dmitrii Pasechnik, Karl-Dieter Crisman

Issue created by migration from https://trac.sagemath.org/ticket/9176

[kcrisman]

comment:1

This file passed doctests in a build of mine on XP.

[kcrisman]

comment:2

But trying the first example by hand leads to a segfault (presumably related to the segfault currently bedeveling Cygwin startup, see #11551).

That is weird. Is it possible that a silent segfault makes a doctest think it passed?

[jpflori]

comment:3

Got lots of failures, apparently because of forking issues, I'll try a rebase.

[jpflori]

comment:4

Also lots of MemoryError for PARI trying to allocate memory.

[kcrisman]

comment:5

Got lots of failures, apparently because of forking issues, I'll try a rebase.

Glad at least one of the forking issues I had cropped up for you :-) Even if it does work on a rebase, don't forget to try by hand as well.

[jpflori]

comment:6

And indeed inside "./sage -gp" I cannot allocatemem(512000000), but only 256000000, not sure why though.

[jpflori]

comment:7

I think I only have one forking issue (among 202 failing tests) caused by ecl which I rebuilt in the end (and potentially did not rebase after that).

[jpflori]

comment:8

And I guess it is http://cygwin.com/cygwin-ug-net/setup-maxmem.html so was expected.

So I'm left with the one forking issue :)

[jpflori]

comment:9

Ok I still get the forking issue after rebasing :( the only solution might be to get a clean install at once (I rebuilt ECL p1 spkg and dependencies after having installed all Sage with the p0).

Not sure how to let Cygwin increase the mx mem used, using peflags on python tells me it could not open the file...

[jpflori]

comment:10

The max mem I can allocate is 502333407 and all the hacks I tried in the registry seem to have no (good or bad) effect.

[jpflori]

comment:11

Ok, I manage to use peflags to modify --cygwin-heap but if I set it to 1024MB then I get forking errors...