Can We Solve Linear Algebra Problems at Extreme Scale and Low Precisions?

Re:Can We Solve Linear Algebra Problems at Extreme Scale and... by adgjlsfhk1 on Friday September 17, 2021 @10:26AM (#28565867)

Yeah. The problem with them is that using double-double based methods gives you 104 bits of precision that works with vectorization (and therefore is faster than x87).

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Re:Can We Solve Linear Algebra Problems at Extreme Scale and... by gpderetta on Friday September 17, 2021 @10:44AM (#28566043)

I assume double-double would be the emulated __float128 type in GCC (or hand written equivalent)? Can GCC vectorize it or it needs to be done by hand?

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Re:Can We Solve Linear Algebra Problems at Extreme Scale and... by jcranmer on Friday September 17, 2021 @11:47AM (#28566851)

__float128 is emulated quad-precision, I think.

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Re:Can We Solve Linear Algebra Problems at Extreme Scale and... by gpderetta on Friday September 17, 2021 @12:04PM (#28567080)

Not exactly, the mantissa is increased, but the exponent is the same as standard double precision, so it is not an IEEE quad.

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