PEP 327: Decimal Data Type

Tim Roberts timr at
Sun Feb 8 07:55:24 CET 2004

anton at (Anton Vredegoor) wrote:
>One possible option would be to provide for some kind of random
>rounding routine for some of the least significant bits of a floating
>point value.

I'm not so sure about this.  It still gives you what seems to be an exact
answer with 15 decimal places, but now you have non-determinism.  The real
answer, I think, is getting people to understand how much of their
real-world measurements are garbage.

>The advantage would be that this would also be usable for
>DSP-like computations that are used in music programming (volume
>adjustments) or in digital video (image rotation). 

Interesting.  I know you were kind of talking off the top of your head, but
can you tell me what leads you to thinking that some low-order randomness
would be helpful in those particular applications?

>Maybe we need a DSP-float instead of a decimal data type? Decimals
>could be used for testing DSP-float implementations.

Can you describe what you mean by DSP-float?  I'm not sure why a DSP should
treat floats any differently than an ordinary processor.
- Tim Roberts, timr at
  Providenza & Boekelheide, Inc.

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