Java Valhalla and Maths support, Floating point

Karen Kinnear karen.kinnear at oracle.com
Thu Mar 8 14:57:50 UTC 2018


Valhalla is not aiming to change floating point behavior underflow/overflow.

So work with the core-libs-dev alias responses from Joe Darcy etc.

thanks,
Karen

> On Mar 8, 2018, at 1:30 AM, A Z <poweruserm at live.com.au> wrote:
> 
> I have found that double and float types in java are heirs to arithmetic underflow and overflow at any use.
> 
> I have found that presently, floating point is an arithmetic approximation.  My problem is that
> 
> the java language needs to be changed here, so that one may have arithmetic accuracy with
> 
> floats and doubles.
> 
> 
> Is Valhalla aiming to rectify the following kinds of shortfalls?  It does strike me that
> 
> the former code calls in already built software could remain compatible with some further
> 
> adjustments.
> 
> 
> I have attempted to, and have more carefully described these problems, via the java bugs database:
> 
> 
> 
> JDK-8190947
> 
> JDK-8197995
> 
> JDK-8190991
> 
> JDK-8190946
> 
> 
> 
> -These types, as things are, must be computationally discarded, used only in terms of push and pull,
> 
> and be programmed around using BigDecimal, which will be a waste of memory,
> 
> program execution speed, and a total confusion due to the lack of any operator
> 
> usage options on BigDecimals.
> 
> 
> 
> -It is the case that setting up BigDecimals can be and is presently a circumstantial waste of memory
> 
> with very many tasks, combined with the fact that the fact that having to use BigDecimal
> 
> method calls is nowhere near as efficient or legible to developers or mathematics and enginner
> 
> programmers (and useful with their time) as
> 
> 
> 
> +, -, *, /, %, +=,-+,*=,/=,%=, ++, --
> 
> 
> 
> .This is a syntax argument largely, but also an instruction argument
> 
> since BigDecimals have to be set up or used with an extra, thereby second, call.
> 
> 
> 
> -It is the case that every other major language includes both floating point and accuracy mode
> 
> options with these two types and or Objects, either as a source code instruction or as a
> 
> compiler switch option.  These languages at least provide both options for floating
> 
> point and mathematical accuracy mode.
> 
> 
> 
> There is also a trigonometric and numerics shortfall when it comes to BigDecimal.
> 
> Java could, fiarly directly, produce a StrictMath equivalent for BigDecimal,
> 
> to return a PI BigDecimal, specified by a BigInteger number of decimal places.
> 
> The same thing can be done for e, Euler's constant.  However, the square root,
> 
> Nth root and powers need to be specified upon a BigDecimal, by means of another BigDecimal.
> 
> BigInteger can just be left, in a way.
> 
> This Oracle lecture seems to suggest such is possible:
> https://www.youtube.com/watch?v=qTKeU_3rhk4
> 
> 
> Can someone please reply to me on these things?
> 
> Does Valhalla aim to eliminate floating point overflow and underflow somehow?
> 
> Could there be some more operator usage included on just the two BigInteger and BigDecimal classes?
> 
> If anyone here knows, could overflow and underflow be changed in SE Java where it stands?
> 
> 



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