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New Approach Could Sink Floating Point Computation
07-16-2019, 12:38 AM
Post: #4
RE: New Approach Could Sink Floating Point Computation
Hi, mfleming:

(07-15-2019 07:50 PM)mfleming Wrote:  Anyway, given the broad range of mathematical discussions on this forum, I thought this article would be of interest to some of the members. [...]

Indeed, thanks for posting (and commenting) the reference.

Quote:Naturally there's plenty of argument over such claims and the posted comments to the article go into some detail about them, including responses by Gustafson himself.

I've read the article and in particular the posted comments, including one by John L. Gustafson, where he says (the highlighting is mine):

John L. Gustafson Wrote:.
Whereas IEEE 754 mandates the setting of flags when there is rounding, underflow, and overflow, four decades have shown that programmers do not use them. Programming languages do not support them [...] And you can’t view the ‘inexact flag” in any language other than assembler.

This is blatantly incorrect, an obvious counterexample is HP-71B BASIC, which fully complies with IEEE 754 and supports all those flags. And of course, you can view the inexact flag as well as all the others directly from BASIC (or the command line for that matter) using BASIC statements, no need to use "assembler".

I don't understand why Gustafson made such incorrect statement after having extensively dealt with Prof. Kahan, which obviously knew everything about the HP-71B and its capable IEEE implementation as part of its BASIC language, and surely must have mentioned it to Gustafson at one time or another.

Perhaps John L. Gustafson doesn't consider HP-71B BASIC a programming language ? Or maybe Prof. Kahan !?. Or both !?


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RE: New Approach Could Sink Floating Point Computation - Valentin Albillo - 07-16-2019 12:38 AM

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