[std-interval] Interval comparison operators

[Alan Eliasen]

George Corliss wrote:
> Does anyone have hard experimental data on the performance costs of NaN?

   Here's some additional data on a different operating system,
processor, and compiler version.  This makes a huge difference!

Processor: Pentium III
Windows 2000
g++ (GCC) 3.4.2 (mingw-special)

-O0:
add1:                   10455 ticks     Sum: 1e+009
addQNaN:                166990 ticks    Sum: 1.#QNAN
addSNaN:                167741 ticks    Sum: 1.#QNAN

-O1:
add1:                   10344 ticks     Sum: 1e+009
addQNaN:                158759 ticks    Sum: 1.#QNAN
addSNaN:                159970 ticks    Sum: 1.#QNAN

-O2:
add1:                   10334 ticks     Sum: 1e+009
addQNaN:                163325 ticks    Sum: 1.#QNAN
addSNaN:                163405 ticks    Sum: 1.#QNAN

-O3:
add1:                   10344 ticks     Sum: 1e+009
addQNaN:                163496 ticks    Sum: 1.#QNAN
addSNaN:                163515 ticks    Sum: 1.#QNAN

   It looks like the cost of doing operations with NaN on this older
architecture is quite high!  I should reiterate that you almost never
actually want to *do* operations with NaN, (you usually just want to
test with isnan() ) but on this platform, it's about 16 times slower!

   As before, sample program is here:

   http://futureboy.us/temp/NaN.cc

-- 
  Alan Eliasen                 |  "When trouble is solved before it
  eliasen at mindspring.com       |    forms, who calls that clever?"
  http://futureboy.us/         |              --Sun Tzu