search for: sqrts

.... Then a metadata-aware codegen translates the fadd with reduced precision, as permitted by the metadata. At runtime, the fadd may return a negative value sometimes, because that could well be within 1000.0 ULPs of an expected non-negative result. But the branch is now gone, and undefined behavior sqrts out. Dan

On 22 Oct 2012, at 18:10, <dag at cray.com> wrote: > None of your proposed solutions is ideal. We really should have > first-class predication in the IR. It's only going to get more > important. Perhaps I am missing something, but isn't a predicated instruction effectively an single-instruction version of an arithmetic operation followed by a select? As we can already

...to avoid traps. A vector select is an entirely different operation. > As we can already represent this in the IR, and already match other > predicated instructions (e.g. on ARM) to this pattern, what is gained > by adding predication directly to the IR? Predicated loads, stores, divides, sqrts, etc. are essential for correctly vectorizing loops with conditionals due to safety concerns. If the loop body has no dangerous operations, then yes, a vector select can be used without problems but it is often slower than predication. Usually the hardware can optimize instructions with certain val...

...,'symptoms','site','multifoc','ctnm','prebca','precystec' , + 'smk','surgery','ptnm.t','nodes','grade','histol','postbca', + 'postcyst','chemo','mets','status'), + sqrts=c('futime')) -- Imputation 1 -- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 <snip> -- Imputation 50 -- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 > MIset <- im...

Ralf Karrenberg <Chareos at gmx.de> writes: > I am sure I've seen some postings on the list concerning architectures > that support predicated execution and how to map that to LLVM IR, I'm > just not sure anymore when and who was involved :). I was one of them. I suggested adding general predication to the LLVM IR but that doesn't look like it's going to happen.

Hi Dan, > I realize that some of these thoughts apply equally to the > prior !fpaccuracy metadata that's been around a while, but I > hadn't looked at it closely until now. > > The !fpmath metadata violates the original spirit of > metadata, which is that metadata is only supposed to exclude > possible runtime conditions, rather than to introduce new > possible

...lect is an entirely different operation. > >> As we can already represent this in the IR, and already match other >> predicated instructions (e.g. on ARM) to this pattern, what is gained >> by adding predication directly to the IR? > > Predicated loads, stores, divides, sqrts, etc. are essential for > correctly vectorizing loops with conditionals due to safety concerns. > If the loop body has no dangerous operations, then yes, a vector select > can be used without problems but it is often slower than predication. > Usually the hardware can optimize instructi...

I realize that some of these thoughts apply equally to the prior !fpaccuracy metadata that's been around a while, but I hadn't looked at it closely until now. The !fpmath metadata violates the original spirit of metadata, which is that metadata is only supposed to exclude possible runtime conditions, rather than to introduce new possible runtime possibilities. The motivation for this is

Hello, not understanding the output of prcomp, I reduce the number of components and the output continues to show cumulative 100% of the variance explained, which can't be the case dropping from 8 components to 3. How do i get the output in terms of the cumulative % of the total variance, so when i go from total solution of 8 (8 variables in the data set), to a reduced number of