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From: "bursejan" <bursejan@1:261/38.remove-i5b-this>
Newsgroups: comp.lang.java.programmer
Subject: Re: Has Android different floats?
Date: Sun, 24 Jun 2018 13:44:42 -0500
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  To: bursejan
From: "bursejan" <bursejan@1:261/38.remove-101j-this>

  To: bursejan
From: bursejan@gmail.com

You can try the same Java code on a Android device. The result will be (Android
 8.0.0):

   Math.pow(10,22)=1.0E22
   Math.pow(10,23)=9.999999999999999E22
   Math.pow(10,24)=1.0E24

I used AIDE-IDE to compile and run the Java directly on the device.

But the above is not the same test case as in my initial post. My initial post
also

tests BigInteger.pow() and BigInteger.doubleValue().

Am Sonntag, 24. Juni 2018 22:35:50 UTC+2 schrieb burs...@gmail.com:
> The test code would be:
>
>         for (int i=22; i<25; i++) {
>            System.out.println("Math.pow(10,"+i+")="+Math.pow(10,i));
>         }
>
> The result (without strictfp modifier to main()) is:
>
>    Math.pow(10,22)=1.0E22
>    Math.pow(10,23)=1.0000000000000001E23
>    Math.pow(10,24)=1.0E24
>
> The result (with strictfp modifier to main()) is:
>
>    Math.pow(10,22)=1.0E22
>    Math.pow(10,23)=1.0000000000000001E23
>    Math.pow(10,24)=1.0E24
>
> Because invoking Math.pow() is not a basic operator +, *, /, etc..
>
> Am Sonntag, 24. Juni 2018 22:31:44 UTC+2 schrieb burs...@gmail.com:
> > You cannot use the strictfp keyword in front
> > of Math.pow(). Thats only for the basic operations.
> >
> > Math.pow() itself is implemented in JDK 1.8 as follows:
> >
> >     public static double pow(double a, double b) {
> >         return StrictMath.pow(a, b); // default impl. delegates to
StrictMath
> >     }
> >
> > Am Sonntag, 24. Juni 2018 21:21:57 UTC+2 schrieb Arne VajhÄ,j:
> > > On 6/24/2018 2:41 PM, j4n bur53 wrote:
> > > > Running a simple test.
> > > > ** is Math.pow(),
> > > > ^ is BigInteger.pow() and then BigInteger.doubleValue().
> > > >
> > > > On Java:
> > > >
> > > >  â  ?- between(15,30,N), X is 10**N-10^N, write(N-X), nl, fail; true.
> > > >  â  15-0.0
> > >
> > > >  â  23-1.6777216E7
> > >
> > > >  â  29-0.0
> > > >  â  30-0.0
> > > >
> > > > On Adroid:
> > > >
> > > >  â  ?- between(15,30,N), X is 10**N-10^N, write(N-X), nl, fail; true.
> > > >  â  15-0.0
> > >
> > > >  â  23-0.0
> > >
> > > >  â  29-1.7592186044416E13
> > > >  â  30-0.0
> > > >
> > > > Has Android different floats?
> > > > Tested jdk1.8.0_152 against Android 8.0.0
> > >
> > > ARM supposedly use standard IEEE 754 FP.
> > >
> > > But I wonder if usage of strictfp would change your results.
> > >
> > > Arne

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