According to IEEE the following doubles exist:
Mantissa Exponent
double 64bit: 52 bit 11 bit
double 80bit: 64 bit 15 bit
In Java only the 64bit double can be directly stored in an instance variable. I would like for whatever reason work with 80bit floats as defined above in Java. I am interested in the full set of arithmetic functions, I/O and trigonometric functions. How could I do that?
One could of course do something along the following lines:
public class DoubleExt {
private long mantissa;
private short exponent;
}开发者_JS百科
And then make a package that interfaces with some of the known C libs for 80bit floats.
But would this be considered the best practice? What about supporting a couple of plattforms and architectures?
Bye
I'm pretty sure primitives won't get you there, but the BigDecimal
class is as good as it gets (for everything except trigonometry).
For trigonometric functions, however, you will have to resort to an external library, like APFloat (see this previous question).
Perhaps BigDecimal is an adequate way for you. But I believe it doesn't provide the full set of mathematic functions.
http://download.oracle.com/javase/1,5.0/docs/api/java/math/BigDecimal.html
The question is already 5 years old. Time to look around
whether there are some new candidates, maybe draw inspiraction
from other languages.
In Racket we find a BigFloat data type:
https://docs.racket-lang.org/math/bigfloat.html
The underlying library is GNU MPFR, a Java interface was started:
https://github.com/kframework/mpfr-java
Is this the only interface so far?
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