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From Wyatt Barnett <wyatt.barn...@gmail.com>
Subject Re: lucenenet git commit: use proper float comparison
Date Thu, 18 Jun 2015 11:01:35 GMT
Nice work Laimonas -- looks like we've got the 3 tests we were focusing on
passing. W00t!

I guess I should get to packaging :)

On Wed, Jun 17, 2015 at 9:59 PM Laimonas Simutis <laimis@gmail.com> wrote:

> After a few different tries, here is the approach that I can get to produce
> consistent and passing results:
>
> https://github.com/apache/lucenenet/pull/150
>
> Let's see what TC shows after it runs that branch... Open for suggestions /
> comments.
>
> On Sat, Jun 6, 2015 at 11:48 AM, Laimonas Simutis <laimis@gmail.com>
> wrote:
>
> > I just tried using the casts and the tests still fail. The rounding
> > differences occur much less frequently but never less they still occur.
> It
> > seems like casting still does not guarantee consistent results.
> >
> > Spent some time researching this issue and found some good links about
> it,
> > for those that are interested:
> >
> >
> >
> http://blogs.msdn.com/b/shawnhar/archive/2009/03/25/is-floating-point-math-deterministic.aspx
> >
> >
> http://stackoverflow.com/questions/6683059/are-floating-point-numbers-consistent-in-c-can-they-be
> > https://randomascii.wordpress.com/2013/07/16/floating-point-determinism/
> >
> >
> >
> > On Mon, Jun 1, 2015 at 3:49 PM, Laimonas Simutis <laimis@gmail.com>
> wrote:
> >
> >> Christopher,
> >>
> >> That looks good to me. Would you be interested in opening up a PR with
> >> the fix for at least the test you were looking at? Do you have ICLA
> signed
> >> and submitted (
> >>
> https://cwiki.apache.org/confluence/display/LUCENENET/Individual+Contributor+License
> >> )?
> >>
> >>
> >> Laimis
> >>
> >>
> >> On Mon, Jun 1, 2015 at 12:34 AM, Christopher Currens <
> >> currens.chris@gmail.com> wrote:
> >>
> >>> We can also do this, with better names:
> >>>
> >>> static class FPUtil
> >>> {
> >>>     [MethodImpl(MethodImplOptions.AggressiveInlining)]
> >>>     [System.Diagnostics.DebuggerStepThrough]
> >>>     public static float AsFloat(float f)
> >>>     {
> >>>         return (float)f;
> >>>     }
> >>> }
> >>>
> >>> The method can have the documentation of the reason why this method is
> >>> necessary and we can get most, if not all, method invocations inlined
> by
> >>> using AggressiveInlining. It's not a guarantee, but I think because the
> >>> method is so small, it will probably be inlined close to 100% of the
> >>> time.
> >>>
> >>> -Christopher
> >>>
> >>> On Sun, May 31, 2015 at 7:36 PM, Laimonas Simutis <laimis@gmail.com>
> >>> wrote:
> >>>
> >>> > Oh my, what a find!! That's amazing, thank you for going through this
> >>> in
> >>> > such detail. I just confirmed that doing the cast for TestFuzzyQuery
> >>> > related failure makes the code work properly on both 32 and 64 bit
> >>> > platforms.
> >>> >
> >>> > I like your approach better because as you discovered, the attribute
> >>> does
> >>> > not always apply.  Is that the conclusion then, we will go with cast
> to
> >>> > float to fix these failures? We can add additional comments in the
> >>> code why
> >>> > the cast exists so that it is clear in the future if someone decides
> to
> >>> > remove it. Unit tests will guard against this as well. Itamar, any
> >>> > objections?
> >>> >
> >>> >
> >>> >
> >>> > On Sun, May 31, 2015 at 10:27 PM, Christopher Currens <
> >>> > currens.chris@gmail.com> wrote:
> >>> >
> >>> > > When I think about it, I think the [NoOptimizations] might just be
> >>> > forcing
> >>> > > some values to be saved to the stack as single-precision floats. I
> >>> think
> >>> > it
> >>> > > may work only for certain methods. The casting issue isn't fixed
> >>> using
> >>> > > NoOptimizations, in either my test program (which is just simple
> >>> floating
> >>> > > point math) or if I add it to several methods using in
> >>> > > TestSimpleExplanations.TestDMQ8 (DisjunctionMaxScorer.Score,
> >>> > > QueryUtils.CollectorAnonymousInnerClassHelper.Collect, and others).
> >>> > >
> >>> > > I actually liked the NoOptimizations thing better, because it was
> >>> more
> >>> > > explicit than casting. At least when I see NoOptimizations in
> >>> source, I
> >>> > > usually assume I'm looking at a workaround for some jit issue.
> Plus,
> >>> > > performance impact could be lessened if the methods where these
> >>> issues
> >>> > > happen are made small enough that NoOptimizations doesn't make much
> >>> of a
> >>> > > difference.
> >>> > >
> >>> > > -Christopher
> >>> > >
> >>> > > On Sun, May 31, 2015 at 7:08 PM, Christopher Currens <
> >>> > > currens.chris@gmail.com> wrote:
> >>> > >
> >>> > > > As I finished writing this, I noticed your reponses above. I
> think
> >>> the
> >>> > > > NoOptimization is probably forcing float truncation which can be
> a
> >>> good
> >>> > > > thing. I wonder if it adversely affects performance.
> >>> > > >
> >>> > > > Anyway, more information on exactly what's happening.
> >>> > > >
> >>> > > > =======================
> >>> > > >
> >>> > > > One last thing. I was able to reproduce this issue in a test
> >>> project,
> >>> > and
> >>> > > > after stepping through the native code, I can confirm that the
> >>> issue is
> >>> > > > limited to 32-bit processes and is a result of the use of the x87
> >>> > > > floating point coprocessor. It is *not* an issue with float to
> >>> double
> >>> > > > conversion, but is caused by the way the jitter might generate
> the
> >>> > code.
> >>> > > > In short, it's not a bug, it's just some unfortunate behavior. I
> >>> can
> >>> > put
> >>> > > > the code in a gist if you want to see it.
> >>> > > >
> >>> > > > Anyway, the issue is that the returned value from Score() is
> >>> stored in
> >>> > > > the FPU register at 80-bit double-extended precision, thanks to
> >>> the x87
> >>> > > > coprocessor. The first call scorer_.Score() which is stored in
> >>> > > skipToScore
> >>> > > > is saved onto the stack using `fstp dword ptr [addr]`. The dword
> >>> ptr
> >>> > > forces
> >>> > > > `fstp` to store it as a single precision. Then, the inline call
> to
> >>> > > > scorer_.Score() inside of the Assert.AreEqual statement is not
> >>> actually
> >>> > > > converted to a single before converted to a double. Instead, the
> >>> return
> >>> > > > value from Score() is stored using `fstp qword ptr [addr]`.
> Because
> >>> > it's
> >>> > > > stored with a qword ptr, `fstp` treats it as a double precision,
> >>> which
> >>> > > > produces a much different value.
> >>> > > >
> >>> > > > When I ran through debugging this, here are the values I saw.
> >>> After
> >>> > > > calculating the first Score():
> >>> > > >
> >>> > > > st0=1.60327445312500e+005
> >>> > > >
> >>> > > > Storing this value into skipToScore uses instructions that stores
> >>> it on
> >>> > > > the stack here with this value:
> >>> > > >
> >>> > > > 160327.44
> >>> > > >
> >>> > > > When calling Assert.Equals, it is pulled back into the st0
> >>> register as:
> >>> > > >
> >>> > > > st0=1.603274375000000000e+0005
> >>> > > >
> >>> > > > with the expected loss of precision. It is compared against the
> >>> > original
> >>> > > > value (since the second call to Store() produces that) and we get
> >>> the
> >>> > > > failure.
> >>> > > >
> >>> > > > I did figure out a way to fix it, although I'm not sure any of it
> >>> is
> >>> > > > ideal. If we explicitly cast to a float, it will truncate the
> value
> >>> > > before
> >>> > > > returning it. Casting in the Score() method is easy, since we can
> >>> wrap
> >>> > > > the statement in parenthesis and prepend it with a cast.
> >>> Alternatively,
> >>> > > > casting can be done on in QueryUtils.cs and you can cast the
> >>> values in
> >>> > > > Assert.AreEquals to float. The downside is resharper complains
> >>> that the
> >>> > > > casts aren't necessary, when they actually do make a difference
> in
> >>> the
> >>> > > > outcome.
> >>> > > >
> >>> > > > -Christopher
> >>> > > >
> >>> > > > On Sun, May 31, 2015 at 6:32 PM, Laimonas Simutis <
> >>> laimis@gmail.com>
> >>> > > > wrote:
> >>> > > >
> >>> > > >> Just tried something with TestFuzzyQuery.TestTieBreaker failure
> >>> that I
> >>> > > >> described in the previous email. Took it out of nunit and built
> a
> >>> > > console
> >>> > > >> app that does what the test is doing. Ran it compiled in Release
> >>> mode
> >>> > on
> >>> > > >> 32
> >>> > > >> bit machine, total hits was 2 (incorrect). Ran it on 64 bit
> >>> machine,
> >>> > > total
> >>> > > >> hits was 5 (correct). Then took the method that is giving issues
> >>> with
> >>> > > >> rounding (CalculateMaxBoost) and marked it with
> >>> > > >> [MethodImpl(MethodImplOptions.NoOptimization)] attribute and now
> >>> the
> >>> > > code
> >>> > > >> returns correct results on both platforms.
> >>> > > >>
> >>> > > >>
> >>> > > >> On Sun, May 31, 2015 at 8:36 PM, Laimonas Simutis <
> >>> laimis@gmail.com>
> >>> > > >> wrote:
> >>> > > >>
> >>> > > >> > Christopher,
> >>> > > >> >
> >>> > > >> > Thanks for confirming that you are seeing the same thing and
> >>> for the
> >>> > > >> > background info as to what potentially is going on. Really
> >>> helpful
> >>> > > >> > information.
> >>> > > >> >
> >>> > > >> > This test can pass at times because of random selection of
> >>> values.
> >>> > The
> >>> > > >> > better test that always fails and contains no randomness
> >>> component
> >>> > to
> >>> > > >> it is
> >>> > > >> > this one:
> >>> > > >> >
> >>> > > >>
> >>> > >
> >>> >
> >>>
> http://teamcity.codebetter.com/viewLog.html?tab=buildLog&logTab=tree&filter=debug&expand=all&buildId=192345#_focus=5721
> >>> > > >> >
> >>> > > >> > In the test, this line in particular is the issue:
> >>> > > >> >
> >>> > > >> >
> >>> > > >> >
> >>> > > >>
> >>> > >
> >>> >
> >>>
> https://github.com/apache/lucenenet/blob/master/src/Lucene.Net.Core/Search/FuzzyTermsEnum.cs#L243
> >>> > > >> >
> >>> > > >> > There is a code path where MaxEdits > 0 is true, termAfter is
> >>> false
> >>> > > and
> >>> > > >> > "Bottom > CalculateMaxBoost(MaxEdits)" gets evaluated as true
> >>> even
> >>> > > >> though
> >>> > > >> > the values should evaluate as equal. I confirm this with the
> >>> same
> >>> > > >> technique
> >>> > > >> > by printing the numbers inside the loop.
> >>> > > >> >
> >>> > > >> > There is no conversion to double going on and I can get the
> >>> test to
> >>> > > fail
> >>> > > >> > less frequently by precalculating max boost outside of the
> >>> "while"
> >>> > > >> > condition but even that just reduces the frequency of failures
> >>> but
> >>> > > does
> >>> > > >> not
> >>> > > >> > totally eliminate it.
> >>> > > >> >
> >>> > > >> > Will continue to investigate / look for solutions on this. In
> >>> the
> >>> > > >> meantime
> >>> > > >> > I am open to any suggestions :)
> >>> > > >> >
> >>> > > >> > On Sun, May 31, 2015 at 2:33 AM, Christopher Currens <
> >>> > > >> > currens.chris@gmail.com> wrote:
> >>> > > >> >
> >>> > > >> >> I was able to confirm that the 32-bit and 64-bit JVMs both
> emit
> >>> > code
> >>> > > >> using
> >>> > > >> >> SSE. So maybe there is something there, or maybe not.
> >>> > > >> >>
> >>> > > >> >> It's weird though, because if I run the test over and over
> >>> (using
> >>> > the
> >>> > > >> >> NUnit
> >>> > > >> >> adapter in visual studio, so x86) it sometimes passes, and
> I'm
> >>> not
> >>> > > sure
> >>> > > >> >> why. You are right, though, it is something related to the
> >>> > conversion
> >>> > > >> >> between float and double. Every time it fails, I output the
> >>> > roundtrip
> >>> > > >> >> string for both skipToScore and scorer_.Score() as floats and
> >>> then
> >>> > > >> casted
> >>> > > >> >> as double. Every single time when it fails, the float values
> >>> are
> >>> > > >> exactly
> >>> > > >> >> the same and those same float values casted to doubles
> produce
> >>> > > >> different
> >>> > > >> >> numbers. I mean, this is what you saw yourself in the tests,
> >>> I'm
> >>> > just
> >>> > > >> here
> >>> > > >> >> to confirm I'm seeing the same thing (and it's puzzling).
> >>> > > >> >>
> >>> > > >> >> I feel like this one is out of our control (maybe a .NET
> bug?)
> >>> and
> >>> > > >> maybe
> >>> > > >> >> the best fix is to to do what you've already done and avoid
> the
> >>> > > >> conversion
> >>> > > >> >> to double altogether via Assert.IsTrue.
> >>> > > >> >>
> >>> > > >> >> -Christopher
> >>> > > >> >>
> >>> > > >> >>
> >>> > > >> >> On Sat, May 30, 2015 at 9:03 PM, Christopher Currens <
> >>> > > >> >> currens.chris@gmail.com> wrote:
> >>> > > >> >>
> >>> > > >> >> > The .NET jitter emits different code to handle floating
> point
> >>> > > >> >> instructions
> >>> > > >> >> > in x86 vs x64. At least on my machine, I noticed that the
> >>> native
> >>> > > >> >> assembly
> >>> > > >> >> > code generated by the jitter when running in x86 uses the
> x87
> >>> > > >> extensions
> >>> > > >> >> > for floating point and in x64 it uses SSE. I believe that
> >>> this is
> >>> > > >> only
> >>> > > >> >> an
> >>> > > >> >> > issue when dealing with single-precision floating point
> >>> numbers,
> >>> > > >> which
> >>> > > >> >> are
> >>> > > >> >> > used pretty much everywhere in search. The reason is
> because
> >>> the
> >>> > > x87
> >>> > > >> >> > extensions, by default, use 80-bit double-extended
> precision
> >>> > > >> internally
> >>> > > >> >> > (thanks, Wikipedia!) whereas x64 uses single-precision
> >>> > instructions
> >>> > > >> (and
> >>> > > >> >> > thus the mantissa is truncated) which means we'll get
> >>> different
> >>> > > >> results
> >>> > > >> >> > between the two architectures.
> >>> > > >> >> >
> >>> > > >> >> > Resharper defaults to x64. If I use the NUnit Test Adapter
> >>> and
> >>> > run
> >>> > > >> the
> >>> > > >> >> > unit tests using visual studio directly, which runs in
> 32-bit
> >>> > > mode, I
> >>> > > >> >> can
> >>> > > >> >> > get the tests to fail almost all the time.
> >>> > > >> >> >
> >>> > > >> >> > This is a good catch. I'm not sure if we should change
> nunit
> >>> to
> >>> > be
> >>> > > >> x64
> >>> > > >> >> > necessarily. It's possible that this is exposing a real
> code
> >>> > issue
> >>> > > >> >> > somewhere, or at least an inconsistency in behavior between
> >>> .NET
> >>> > > and
> >>> > > >> >> Java.
> >>> > > >> >> > I think I might pull down the java code and see if there's
> a
> >>> > > >> difference
> >>> > > >> >> in
> >>> > > >> >> > this test between a 32-bit and 64-bit JVM. I don't know
> what
> >>> kind
> >>> > > of
> >>> > > >> >> > assembly instructions that are emitted by Java's jitter.
> >>> > > >> >> >
> >>> > > >> >> > -Christopher
> >>> > > >> >> >
> >>> > > >> >> > On Sat, May 30, 2015 at 6:47 PM, Laimonas Simutis <
> >>> > > laimis@gmail.com>
> >>> > > >> >> > wrote:
> >>> > > >> >> >
> >>> > > >> >> >> FINALLY I am able to reproduce it locally. Looking through
> >>> TC
> >>> > > build
> >>> > > >> I
> >>> > > >> >> >> noticed this:
> >>> > > >> >> >>
> >>> > > >> >> >> Running NUnit-2.6.3 tests under .NET Framework v4.0 x86
> >>> > > >> >> >>
> >>> > > >> >> >> Note x86... So instead of running test via Resharper and
> >>> built
> >>> > in
> >>> > > >> >> NUnit, I
> >>> > > >> >> >> ran it  with nunit 2.6.3 via command line. Tests fail with
> >>> the
> >>> > odd
> >>> > > >> >> float
> >>> > > >> >> >> issues if I run it with nunit-x86, and pass if I run it
> with
> >>> > > >> nunit.exe
> >>> > > >> >> >> (both version 2.6.3). I am on a 64 bit machine, and so are
> >>> the
> >>> > TC
> >>> > > >> build
> >>> > > >> >> >> agents it seems.
> >>> > > >> >> >>
> >>> > > >> >> >> I am still not sure why this causes the failures to occur,
> >>> but
> >>> > do
> >>> > > we
> >>> > > >> >> need
> >>> > > >> >> >> to adjust what nunit build we use to run the tests?
> >>> > > >> >> >>
> >>> > > >> >> >> On Sat, May 30, 2015 at 4:28 PM, Laimonas Simutis <
> >>> > > laimis@gmail.com
> >>> > > >> >
> >>> > > >> >> >> wrote:
> >>> > > >> >> >>
> >>> > > >> >> >> >
> >>> > > >> >> >> >
> >>> > > >> >> >> > On Sat, May 30, 2015 at 4:01 PM, Itamar Syn-Hershko <
> >>> > > >> >> itamar@code972.com
> >>> > > >> >> >> >
> >>> > > >> >> >> > wrote:
> >>> > > >> >> >> >
> >>> > > >> >> >> >> And when you refactor _scorer.Score() to be in a
> >>> different
> >>> > line
> >>> > > >> it
> >>> > > >> >> >> passes
> >>> > > >> >> >> >> 100% of the time on all platforms? that doesn't sound
> >>> right.
> >>> > > >> >> >> >>
> >>> > > >> >> >> >
> >>> > > >> >> >> > It continues to pass on mine (I can never get those to
> >>> fail
> >>> > > >> locally),
> >>> > > >> >> >> and
> >>> > > >> >> >> > ran the test several times on TC and it passed. I know,
> it
> >>> > > sounds
> >>> > > >> >> odd,
> >>> > > >> >> >> I am
> >>> > > >> >> >> > at a loss to explain it.
> >>> > > >> >> >> >
> >>> > > >> >> >> >
> >>> > > >> >> >> >>
> >>> > > >> >> >> >> Also, not in front of VS now, but AreEquals should
> >>> already be
> >>> > > >> doing
> >>> > > >> >> >> this
> >>> > > >> >> >> >> epsilon thing no?
> >>> > > >> >> >> >>
> >>> > > >> >> >> >
> >>> > > >> >> >> > That's what I thought too. The only odd thing there is
> no
> >>> > > "float"
> >>> > > >> >> >> overload
> >>> > > >> >> >> > and only "double" so not sure if conversion from float
> to
> >>> > double
> >>> > > >> >> might
> >>> > > >> >> >> be
> >>> > > >> >> >> > introducing rounding issues here too. That's why I
> >>> replaced it
> >>> > > >> with
> >>> > > >> >> >> epsilon
> >>> > > >> >> >> > just to see what would happen and it still failed so
> then
> >>> I
> >>> > went
> >>> > > >> with
> >>> > > >> >> >> > precalculating scorer_.Score() before comparison just to
> >>> see
> >>> > > what
> >>> > > >> >> would
> >>> > > >> >> >> > happen.
> >>> > > >> >> >> >
> >>> > > >> >> >> > And check this out. I put the comparison back like it
> >>> used to
> >>> > be
> >>> > > >> >> >> > (Assert.AreEquals) and wrapped in catch to output to
> >>> console
> >>> > the
> >>> > > >> >> values:
> >>> > > >> >> >> >
> >>> > > >> >> >> > float skipToScore = scorer_.Score();
> >>> > > >> >> >> > try
> >>> > > >> >> >> > {
> >>> > > >> >> >> >     Assert.AreEqual(skipToScore, scorer_.Score(),
> MaxDiff,
> >>> > > >> "unstable
> >>> > > >> >> >> > skipTo(" + i + ") score!");
> >>> > > >> >> >> > }
> >>> > > >> >> >> > catch (AssertionException ex)
> >>> > > >> >> >> > {
> >>> > > >> >> >> >     Console.WriteLine("Failed, these two were deemed not
> >>> > > equal:");
> >>> > > >> >> >> >     Console.WriteLine(skipToScore.ToString("R"));
> >>> > > >> >> >> >     Console.WriteLine(scorer_.Score().ToString("R"));
> >>> > > >> >> >> >     throw;
> >>> > > >> >> >> > }
> >>> > > >> >> >> >
> >>> > > >> >> >> > Look at the output on TC:
> >>> > > >> >> >> >
> >>> > > >> >> >> > Test(s) failed.   unstable skipTo(3) score!
> >>> > > >> >> >> >   Expected: 115019.984375d +/- 0.0010000000474974513d
> >>> > > >> >> >> >   But was:  115019.98828125d
> >>> > > >> >> >> >
> >>> > > >> >> >> > ------- Stderr: -------
> >>> > > >> >> >> > Failed, these two were deemed not equal:
> >>> > > >> >> >> > 115019.984
> >>> > > >> >> >> > 115019.984
> >>> > > >> >> >> >
> >>> > > >> >> >> > You can see how the floats were converted to doubles and
> >>> > > >> furthermore
> >>> > > >> >> how
> >>> > > >> >> >> > when I call Score() in catch section, it returns
> >>> 115019.984
> >>> > yet
> >>> > > >> when
> >>> > > >> >> it
> >>> > > >> >> >> was
> >>> > > >> >> >> > called in Assert it is outputting 115019.98828125d. and
> >>> 0.988
> >>> > > and
> >>> > > >> is
> >>> > > >> >> off
> >>> > > >> >> >> > from 0.984 by more than 0.001 (which is the value of
> >>> MaxDiff).
> >>> > > >> >> >> >
> >>> > > >> >> >> >
> >>> > > >> >> >> >
> >>> > > >> >> >> >
> >>> > > >> >> >> >>
> >>> > > >> >> >> >> --
> >>> > > >> >> >> >>
> >>> > > >> >> >> >> Itamar Syn-Hershko
> >>> > > >> >> >> >> http://code972.com | @synhershko <
> >>> > > https://twitter.com/synhershko
> >>> > > >> >
> >>> > > >> >> >> >> Freelance Developer & Consultant
> >>> > > >> >> >> >> Lucene.NET committer and PMC member
> >>> > > >> >> >> >>
> >>> > > >> >> >> >> On Sat, May 30, 2015 at 10:46 PM, Laimonas Simutis <
> >>> > > >> >> laimis@gmail.com>
> >>> > > >> >> >> >> wrote:
> >>> > > >> >> >> >>
> >>> > > >> >> >> >> > Itamar,
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > These float comparison are killing me :) I am pretty
> >>> sure
> >>> > all
> >>> > > >> the
> >>> > > >> >> >> >> remaining
> >>> > > >> >> >> >> > failures in core tests are related to float issues.
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > I am trying to use epsilon here by changing
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > AreEqual(skipToScore, scorer_.Score(), MaxDiff) to
> >>> > > >> >> >> >> > IsTrue(Math.Abs(skipToScore - scorer_.Score()) <
> >>> MaxDiff).
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > It is similar to the link you provided except I am
> not
> >>> > > >> >> >> >> > handling infinite and values close to 0, which are
> not
> >>> > > expected
> >>> > > >> >> and
> >>> > > >> >> >> do
> >>> > > >> >> >> >> not
> >>> > > >> >> >> >> > occur in this test.
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > I can get this test to pass by taking out
> >>> scorer_.Score()
> >>> > > >> >> calculation
> >>> > > >> >> >> >> and
> >>> > > >> >> >> >> > calculating it separately and then comparing, like
> >>> this:
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > var secondScore = scorer_.Score();
> >>> > > >> >> >> >> > IsTrue(Math.Abs(skipToScore - secondScore) <
> MaxDiff).
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > In this case, the scorer_.Score() is doing a bunch of
> >>> float
> >>> > > >> adds
> >>> > > >> >> /
> >>> > > >> >> >> >> > multiplies (
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >>
> >>> > > >> >> >>
> >>> > > >> >>
> >>> > > >>
> >>> > >
> >>> >
> >>>
> https://github.com/apache/lucenenet/blob/master/src/Lucene.Net.Core/Search/DisjunctionMaxScorer.cs#L58
> >>> > > >> >> >> >> > )
> >>> > > >> >> >> >> > so I can see where rounding error could come in but
> >>> still
> >>> > > >> cannot
> >>> > > >> >> >> explain
> >>> > > >> >> >> >> > how it consistently fails on some env and not the
> >>> others.
> >>> > > Also
> >>> > > >> >> have
> >>> > > >> >> >> no
> >>> > > >> >> >> >> idea
> >>> > > >> >> >> >> > how to proceed with this issue besides changing the
> >>> order
> >>> > of
> >>> > > >> >> >> >> calculations,
> >>> > > >> >> >> >> > like I did with the above to get it to pass. Just
> don't
> >>> > feel
> >>> > > >> >> >> confident
> >>> > > >> >> >> >> that
> >>> > > >> >> >> >> > there is no bigger issue somewhere else.
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > Laimis
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > On Sat, May 30, 2015 at 2:56 PM, Itamar Syn-Hershko <
> >>> > > >> >> >> itamar@code972.com
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > wrote:
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >> > > Float comparison is not as trivial - you should
> >>> probably
> >>> > > use
> >>> > > >> >> >> epsilon
> >>> > > >> >> >> >> --
> >>> > > >> >> >> >> > see
> >>> > > >> >> >> >> > > http://stackoverflow.com/a/3875619/135701 for
> >>> example
> >>> > > >> >> >> >> > >
> >>> > > >> >> >> >> > > --
> >>> > > >> >> >> >> > >
> >>> > > >> >> >> >> > > Itamar Syn-Hershko
> >>> > > >> >> >> >> > > http://code972.com | @synhershko <
> >>> > > >> >> https://twitter.com/synhershko>
> >>> > > >> >> >> >> > > Freelance Developer & Consultant
> >>> > > >> >> >> >> > > Lucene.NET committer and PMC member
> >>> > > >> >> >> >> > >
> >>> > > >> >> >> >> > > On Sat, May 30, 2015 at 9:50 PM, <
> laimis@apache.org>
> >>> > > wrote:
> >>> > > >> >> >> >> > >
> >>> > > >> >> >> >> > > > Repository: lucenenet
> >>> > > >> >> >> >> > > > Updated Branches:
> >>> > > >> >> >> >> > > >   refs/heads/failingtests bdf2899a0 -> 6a81f8606
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > > use proper float comparison
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > > Project:
> >>> > > >> >> http://git-wip-us.apache.org/repos/asf/lucenenet/repo
> >>> > > >> >> >> >> > > > Commit:
> >>> > > >> >> >> >> >
> >>> > > >>
> http://git-wip-us.apache.org/repos/asf/lucenenet/commit/6a81f860
> >>> > > >> >> >> >> > > > Tree:
> >>> > > >> >> >> >>
> >>> > http://git-wip-us.apache.org/repos/asf/lucenenet/tree/6a81f860
> >>> > > >> >> >> >> > > > Diff:
> >>> > > >> >> >> >>
> >>> > http://git-wip-us.apache.org/repos/asf/lucenenet/diff/6a81f860
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > > Branch: refs/heads/failingtests
> >>> > > >> >> >> >> > > > Commit: 6a81f860671ab98fb7cd595af317b3d8521acc21
> >>> > > >> >> >> >> > > > Parents: bdf2899
> >>> > > >> >> >> >> > > > Author: Laimonas Simutis <laimis@gmail.com>
> >>> > > >> >> >> >> > > > Authored: Sat May 30 14:49:35 2015 -0400
> >>> > > >> >> >> >> > > > Committer: Laimonas Simutis <laimis@gmail.com>
> >>> > > >> >> >> >> > > > Committed: Sat May 30 14:49:35 2015 -0400
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >>
> >>> > > >> >>
> >>> > >
> >>> ----------------------------------------------------------------------
> >>> > > >> >> >> >> > > >
> src/Lucene.Net.TestFramework/Search/QueryUtils.cs
> >>> | 4
> >>> > > ++--
> >>> > > >> >> >> >> > > >  1 file changed, 2 insertions(+), 2 deletions(-)
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >>
> >>> > > >> >>
> >>> > >
> >>> ----------------------------------------------------------------------
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > >
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >>
> >>> > > >> >> >>
> >>> > > >> >>
> >>> > > >>
> >>> > >
> >>> >
> >>>
> http://git-wip-us.apache.org/repos/asf/lucenenet/blob/6a81f860/src/Lucene.Net.TestFramework/Search/QueryUtils.cs
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >>
> >>> > > >> >>
> >>> > >
> >>> ----------------------------------------------------------------------
> >>> > > >> >> >> >> > > > diff --git
> >>> > > >> a/src/Lucene.Net.TestFramework/Search/QueryUtils.cs
> >>> > > >> >> >> >> > > >
> b/src/Lucene.Net.TestFramework/Search/QueryUtils.cs
> >>> > > >> >> >> >> > > > index 1156eee..6615d4c 100644
> >>> > > >> >> >> >> > > > ---
> >>> a/src/Lucene.Net.TestFramework/Search/QueryUtils.cs
> >>> > > >> >> >> >> > > > +++
> >>> b/src/Lucene.Net.TestFramework/Search/QueryUtils.cs
> >>> > > >> >> >> >> > > > @@ -478,8 +478,8 @@ namespace Lucene.Net.Search
> >>> > > >> >> >> >> > > >
> >>> > Assert.IsTrue(scorer_.Advance(i)
> >>> > > >> !=
> >>> > > >> >> >> >> > > > DocIdSetIterator.NO_MORE_DOCS, "query collected "
> >>> + doc
> >>> > > + "
> >>> > > >> >> but
> >>> > > >> >> >> >> > skipTo("
> >>> > > >> >> >> >> > > +
> >>> > > >> >> >> >> > > > i + ") says no more docs!");
> >>> > > >> >> >> >> > > >                          Assert.AreEqual(doc,
> >>> > > >> scorer_.DocID(),
> >>> > > >> >> >> >> "query
> >>> > > >> >> >> >> > > > collected " + doc + " but skipTo(" + i + ") got
> to
> >>> " +
> >>> > > >> >> >> >> > scorer_.DocID());
> >>> > > >> >> >> >> > > >                          float skipToScore =
> >>> > > >> scorer_.Score();
> >>> > > >> >> >> >> > > > -
> >>> Assert.AreEqual(skipToScore,
> >>> > > >> >> >> >> scorer_.Score(),
> >>> > > >> >> >> >> > > > MaxDiff, "unstable skipTo(" + i + ") score!");
> >>> > > >> >> >> >> > > > -                        Assert.AreEqual(score,
> >>> > > >> skipToScore,
> >>> > > >> >> >> >> MaxDiff,
> >>> > > >> >> >> >> > > > "query assigned doc " + doc + " a score of <" +
> >>> score +
> >>> > > ">
> >>> > > >> but
> >>> > > >> >> >> >> skipTo("
> >>> > > >> >> >> >> > > + i
> >>> > > >> >> >> >> > > > + ") has <" + skipToScore + ">!");
> >>> > > >> >> >> >> > > > +
> >>> > > >> Assert.IsTrue(Math.Abs(skipToScore -
> >>> > > >> >> >> >> > > > scorer_.Score()) < MaxDiff, "unstable skipTo(" +
> i
> >>> + ")
> >>> > > >> >> score!");
> >>> > > >> >> >> >> > > > +
> >>> > Assert.AreEqual(Math.Abs(score -
> >>> > > >> >> >> >> skipToScore)
> >>> > > >> >> >> >> > <
> >>> > > >> >> >> >> > > > MaxDiff, "query assigned doc " + doc + " a score
> >>> of <"
> >>> > +
> >>> > > >> >> score +
> >>> > > >> >> >> ">
> >>> > > >> >> >> >> but
> >>> > > >> >> >> >> > > > skipTo(" + i + ") has <" + skipToScore + ">!");
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > >                          // Hurry things along if
> >>> they
> >>> > > are
> >>> > > >> >> going
> >>> > > >> >> >> >> slow
> >>> > > >> >> >> >> > (eg
> >>> > > >> >> >> >> > > >                          // if you got SimpleText
> >>> codec
> >>> > > >> this
> >>> > > >> >> will
> >>> > > >> >> >> >> kick
> >>> > > >> >> >> >> > > in):
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > > >
> >>> > > >> >> >> >> > >
> >>> > > >> >> >> >> >
> >>> > > >> >> >> >>
> >>> > > >> >> >> >
> >>> > > >> >> >> >
> >>> > > >> >> >>
> >>> > > >> >> >
> >>> > > >> >> >
> >>> > > >> >>
> >>> > > >> >
> >>> > > >> >
> >>> > > >>
> >>> > > >
> >>> > > >
> >>> > >
> >>> >
> >>>
> >>
> >>
> >
>

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