[geos-devel] 3.9.0beta2

[Regina Obe]

+1 for releasing.  As long as it can compile and still works we can sort out
the details in next release.

> -----Original Message-----
> From: geos-devel [mailto:geos-devel-bounces at lists.osgeo.org] On Behalf Of
> Paul Ramsey
> Sent: Friday, December 4, 2020 4:11 PM
> To: GEOS Development List <geos-devel at lists.osgeo.org>
> Subject: Re: [geos-devel] 3.9.0beta2
> 
> 
> > On Dec 3, 2020, at 10:18 PM, Sebastiaan Couwenberg <sebastic at xs4all.nl>
> wrote:
> >
> > On 12/3/20 12:17 AM, Paul Ramsey wrote:
> >> without any further ado, here's a beta2 release for your testing
pleasure
> >
> > testrunner fails on arm64, ppc64el, powerpc, ppc64, riscv64:
> 
> Have we ever passed? Perhaps I made a big mistake removing ttmath.
> 
> Anyways, here's what I've learned today, testing on an AWS ARM64 server.
> 
> * Still no obvious reason why these platforms shouldn't just work, if they
> implement IEEE conforming operations on double.
> * There's something called FLT_EVAL_METHOD in <cfloat> which might
> indicate non-IEEE handling of double, but... my test server insists it is
> FLT_EVAL_METHOD == 0 "evaluate just to the range and precision of the
> type".
> 
> Wondering if there was a brutal hack-around, and noting that "long double"
> is increasingly a "thing", I took our DD class, and hacked out all the
smarts and
> substituted long double implementations.
> 
> https://github.com/pramsey/geos/tree/dd-arm
> 
> Interestingly, this implementation passes all the geos::math::DD tests!
The
> ARM64 long double appears to have a full 128bit implementation. Running
> the same thing on Intel x64 fails a number of tests. This is probably
because
> the long double implementation on x64 has only 80 bits (according to the
> internet).
> 
> Does all this test passing mean that a direct use of long double will work
on
> platforms that support it? Apparently not. The ARM build still fails on
quite a
> few tests of varying sorts, just not on the DD tests.
> 
> 	 90 - unit-capi-GEOSVoronoiDiagram (Failed)
> 	140 - unit-linearref-LengthIndexedLine (Failed)
> 	208 - general-TestCentroid (Failed)
> 	260 - issue-issue-geos-275 (Failed)
> 	267 - issue-issue-geos-398 (Failed)
> 	349 - robust-TestOverlay-pg-list (Failed)
> 
> Where does this leave us? With a long research project on ARM64 to track
> down why these tests fail and/or why the DD implementation fails.
> 
> Should we still release? I think so. While ARM and other niche platforms
are
> coming down the pike, it doesn't make sense to delay. GEOS isn't "broken"
> on those platforms so much as "not perfect".
> 
> P.
> 
> 
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