In going from double precision to quad (or higher) precision,
- roughly how much of a performance hit is taken on various architectures and frameworks. Do floating point operations take twice as much time? Ten times as much time? One hundred times as much time?
- What frameworks are currently available that support quad precision for large-scale computation?
I'm interested in answers both about software simulation of quad precision with doubles, as well as quad precision that is done natively in hardware.
Disclaimer: Obviously given a problem requiring quad precision, the first step is to try to reformulate or restructure it so that it doesn't need quad precision anymore. Suppose for the sake of answering this question that such a reformulation of the problem is not possible and quad precision is truly needed.