victotronics

victotronics t1_ire6ha5 wrote

Behavior under roundoff. Floating point numbers are not actually mathematical numbers so all algorithms are inexact. You want them to be not too inexact: small perturbations should give only small errors. The fact that STrassen (and other algorithms) sometimes subtract quantities means that you can have numerical cancellation.

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victotronics t1_ir9f2a0 wrote

Ok, I'm no expert but

> improves on Strassen’s two-level algorithm for the first time, to our knowledge, since its discovery 50 years ago

looks very suspicious. There has been *tons* of work on improving Strassen. It would be mind-blowing if they didn't know about that research.

Then: Strassen and its further developments are theoretical curiosities. Numerically they suffer from grave instabilities.

This stuff should really be posted in r/math.

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