Comments on: Supercomputing Frontiers 2015: The 101×10^2 Problem. Solution: Unums http://www.vrworld.com/2015/03/17/supercomputing-frontiers-2015-the-101x102-problem/ Thu, 09 Apr 2015 17:57:00 +0000 hourly 1 http://wordpress.org/?v=4.1.1 By: John Gustafson http://www.vrworld.com/2015/03/17/supercomputing-frontiers-2015-the-101x102-problem/#comment-10670 Tue, 24 Mar 2015 18:20:00 +0000 http://www.vrworld.com/?p=50121#comment-10670 And a correction to the “101×10^2 floating point (which adds up to 64-bits)” part: That should have been “1.01×10^2″ or 101, which is how many years ago floating point was invented. It has nothing to do with 64 bits; it’s just that 64-bit floats now are the dominant size used in high-performance computing (HPC).

The reference to “faster horse” was a quotation by Henry Ford soon after he had introduced the first commercially successful automobile: “If I had asked my customers what they wanted, they would have asked for a faster horse.” The HPC community asking for faster floating point, with all of its rounding errors and other drawbacks, is a lot like asking for a faster horse instead of asking what comes after horses as a means of transportation.

The Mathematica notebook is written, of course, in Mathematica; it needs to be ported to C to make it practical to try the format on larger applications to see if it is ready to go mainstream.

Many thanks to Sam Reynolds for this writeup!

]]> By: David Gustafson http://www.vrworld.com/2015/03/17/supercomputing-frontiers-2015-the-101x102-problem/#comment-10662 Mon, 23 Mar 2015 22:08:00 +0000 http://www.vrworld.com/?p=50121#comment-10662 Great writeup – well stated summary in a very digestible article. One small tweak is that unums are not necessarily exactly 29 bits, but the meta-data of unums allows for a flexible ‘environment’ of fraction and exponent bits. With a standard environment 29 bits is reasonable for most operations. … not completely dissimilar to quad/double/half precision IEEE floats.

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