[Numpy-discussion] Does float16 exist?

[Anne Archibald]

On 08/01/2008, Charles R Harris <charlesr.harris at gmail.com> wrote:

> I'm starting to get interested in implementing float16 support ;) My
> tentative program goes something like this:
>
> 1) Add the operators to the scalar type. This will give sorting, basic
> printing, addition, etc.
> 2) Add conversions to other types. This will allow promotion of data to
> currently supported types.
> 3) Unoptimized BLAS or ATLAS additions for the type. This would give array
> operations.
> 4) Figure out what the precedence relations are.
>
> Can you add some details to this roadmap? It also strikes me that this
> exercise can be repeated for quad precision floats, so might be a good
> preparation for future IEEE types like the proposed decimal floating types.
> Note that we are going to need some way to distinguish quads and extended
> precision types on 64bit platforms, as both will both register as float128
> in the current notation. Decimal floats can be added with the notation
> decimal64, etc.

How were you planning to implement the basic mathematics (addition,
multiplication, trig, what have you)? Were you planning to code all
that from scratch or is there a 16-bit float math library? Or were you
planning to make this work only on machines with 16-bit math hardware?
Or ship it out to a graphics card?

Without hardware support, people may be happier using 16-bit floats
only for on-disk storage...

Anne