[Python-Dev] Expert floats

[Greg Ewing]

Andrew Koenig <ark-mlist at att.net>:

> Decimal floating-point has almost all the pitfalls of binary
> floating-point, yet I do not see anyone arguing against decimal
> floating-point on the basis that it makes the pitfalls less
> apparent.

But they're not the pitfalls at issue here. The pitfalls at
issue are the ones due to binary floating point behaving
*differently* from decimal floating point.

Most people's mental model of arithmetic, including floating
point, works in decimal. They can reason about it based on
their experience with pocket calculators. They don't have
any experience with binary floating point, though, so any
additional oddities due to that are truly surprising and
mysterious to them.

Greg Ewing, Computer Science Dept, +--------------------------------------+
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