Loss of precision errors in FP conversions

[Robert Jacques]

On Wed, 20 Apr 2011 06:23:01 -0400, bearophile <bearophileHUGS at lycos.com>  
wrote:

> Robert Jacques:
>
>> I do GP GPU work, so I use floats all the time. They're also useful for
>> data storage purposes.
>
> Today GPUs are just starting to manage doubles efficiently (Tesla?).

IIRC, the Fermi Tesla cards do doubles at about 1/2 float speed, so  
relatively to other GPUs, they are both the most efficient, and have the  
best performance. So if there was something that really needed them, I'd  
use them. But doubles requires more double the registers and double the  
memory bandwidth, both of which make dramatic performance differences  
(depending on code). So I'll be sticking to floats and halves for the  
foreseeable future.