On Sunday, 29 June 2014 at 18:13:59 UTC, Russel Winder via
Digitalmars-d wrote:
On Sun, 2014-06-29 at 07:59 -0700, Andrei Alexandrescu via
Digitalmars-d
wrote:
[…]
A friend who works at a hedge fund (after making the rounds to
the NYC large financial companies) told me that's a myth. Any
nontrivial calculation involving money (interest, fixed
income, derivatives, ...) needs floating point. He never
needed more than double.
Very definitely so. Fixed point or integer arithmetic for simple
"household" finance fair enough, but for "finance house"
calculations
you generally need 22+ significant denary digits to meet with
compliance
requirements.
Many people seem to have the bizarre idea that floating point is
less accurate than integer arithmetic. As if storing a value into
a double makes it instantly "fuzzy", or something.
In fact, providing that the the precision is large enough, every
operation that is exact in integers, is exact in floating point
as well.
And if you perform a division using integers, you've silently
lost precision.
So I'm not sure what benefit you'd gain by eschewing floating
point.
