[E-Lang] Operators #6: Multiplicative operators

[Mark S. Miller]

At 08:18 AM Tuesday 4/10/01, Karp, Alan wrote:
>Mark Miller wrote:
>>
>> x / y, when x and y are either integers or float64s, evaluates to the 
>> floating point number that's the appropriate approximation to the real 
>> quotient by the IEEE round-to-even rule (the rounding rule governing all 
>> floating point arithmetic in Java and E.)  When x and y are float64s, "/" 
>> has the same meaning in E as in Java.
>I think there needs to be a way to control the IEEE rounding mode.  It's 
>particularly important when writing code to implement math functions like 
>log, exp, etc.  While I expect there to be library routines for these, 
>special rounding modes are often used for computing special functions, such 
>as Bessel functions and spherical harmonics.

Even once there's an ENative, E-on-pure-Java will continue to be one of the 
important implementations of E, and may continue to be *the* important 
implementation.  As a result, E can only specify that which can be 
reasonably implemented in standard pure Java.  So regarding float64s and 
IEEE, E conforms to "the deterministic subset of IEEE supported by standard 
pure Java".

Is there any way in standard pure Java to control the rounding mode?


>Round-to-even is the proper 
>default.  By the way, this same statement on rounding is needed for +, -, 
>and * as well. 

Done.


        Cheers,
        --MarkM