======= At 2005-06-03, 00:25:02 bear wrote: =======

>
>In particular, be careful not to assume that all complex numbers
>are internally represented in the same way; several implementations,
>I believe, use both polar and cartesian representations internally.

Agree. And I think internal polar representations is more prefered
than cartesian in some cases.

>
>Finally, from a mathematical point of view, a number is either
>inexact or exact; this includes complex numbers.  A few
>implementations allow differing exactness in the real and
>imaginary parts of a complex number.  This is a fact, but the
>fact lies at some intermediate position between being a mere
>artifact of the representation and a mathematical error.
>Consult a number theorist to understand more fully the nature
>of this error; it is beyond my feeble ability to explicate.
>

What if we know (exactly) a number is an imaginary number, but only
know ineaxtly it's magnitude?  "0+1.0i" seems nature.

And for polar representations, a number with exact angle but inexact
magnitude also seems nature.

-
Chongkai Zhu