search for: reciproc

Does R graphics have a way to easily label the horizontal axis by the reciprocal of the scaled value? -- View this message in context: http://r.789695.n4.nabble.com/Graphics-Reciprocal-labeling-tp3949054p3949054.html Sent from the R help mailing list archive at Nabble.com.

...mbrella" to implicitly turn on all the lower-level fast-math-flags, causes some fundamental problems. Those fundamental problems are related to situations where a user wants to disable a portion of the fast-math behavior. For example, to enable all the fast-math transformations except for the reciprocal-math transformation, a command like the following is what a user would expect to work: clang++ -O2 -ffast-math -fno-reciprocal-math -c foo.cpp But that isn't what it's doing. I believe this is a serious problem, but I also want to avoid over-stating the seriousness. To be explicit,...

...Jim Grosbach <grosbach at apple.com> wrote: >> >> Hi Chad, >> >> This is a great transform to do, but you’re right that it’s only safe >> under fast-math. This is particularly interesting when the original divisor >> is a constant so you can materialize the reciprocal at compile-time. You’re >> right that in either case, this optimization should only kick in when there >> is more than one divide instruction that will be changed to a mul. >> >> >> It can be worthwhile to do this even in the case where there is only a >> singl...

I believe that this may be more appropriate here in r-devel than in r-help. The normal hazard function, or reciprocal Mill's Ratio, may be obtained in R as dnorm(z)/(1 - pnorm(z)) or, better, as dnorm(z)/pnorm(-z) for small values of z. The latter formula breaks dowm numerically for me (running R 2.4.1 under Windows XP 5.1 SP 2) for values of z near 37.4 or greater. Looking at the pnorm documentation I see...

...vel fast-math-flags, > causes > > some fundamental problems. Those fundamental problems are related to > > situations where a user wants to disable a portion of the fast-math > behavior. > > For example, to enable all the fast-math transformations except for the > > reciprocal-math transformation, a command like the following is what a > user > > would expect to work: > > clang++ -O2 -ffast-math -fno-reciprocal-math -c foo.cpp > > But that isn't what it's doing. > > I believe this is a serious problem, but I also want to avoid >...

--- On Thu, 9/20/12, Jim Grosbach <grosbach at apple.com> wrote: From: Jim Grosbach <grosbach at apple.com> Subject: Re: [LLVMdev] Proposal: New DAG node type for reciprocal operation To: "Weiming Zhao" <weimingz at codeaurora.org> Cc: llvmdev at cs.uiuc.edu Date: Thursday, September 20, 2012, 3:32 PM Sounds like a reasonable fit for a target-specific DAG combine. I suspect a target specific node wouldn't be necessary and the patterns could be ma...

...ector type legalize. Thanks, Weiming From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On Behalf Of shahid shahid Sent: Thursday, September 20, 2012 10:06 PM To: Weiming Zhao; Jim Grosbach Cc: llvmdev at cs.uiuc.edu Subject: Re: [LLVMdev] Proposal: New DAG node type for reciprocal operation --- On Thu, 9/20/12, Jim Grosbach <grosbach at apple.com<mailto:grosbach at apple.com>> wrote: From: Jim Grosbach <grosbach at apple.com<mailto:grosbach at apple.com>> Subject: Re: [LLVMdev] Proposal: New DAG node type for reciprocal operation To: "Weimi...

...he answer a user wants with GCC (using fast-math) and we get an answer they view as "wrong", doesn't mean it's a bug of ours and that we need to change to get the same answer as GCC. That's not what our goal of GCC compatibility means to me. But we do have a switch '-fno-reciprocal-math' that we accept, and even process/implement to some extent. But that implementation has a bug. Fixing that bug so that when a user says '-ffast-math -fno-reciprocal-math', we enable the fast-math transformations but explicitly disable the reciprocal transformations is, in my vi...

...mon question and I am really disappointed that I could not find a solution. I am trying to calculate Mahanalobis distances in a data frame, where I have several hundreds groups and several hundreds of variables. Whatever I do, however I subset it I get the "system is computationally singular: reciprocal condition number" error. I know what it means and I know what should be the problem, but there is no way this is a singular matrix. I have uploaded the input file to my ftp: http://mkk.szie.hu/dep/talt/lv/CentInpDuplNoHeader.txt It is a tab delimited txt file with no headers. I tried the...

Hi uRsers, when inverting a 2 by 2 matrix using solve, I encountered a error message: solve.default(sigma, tol = 1e-07) : system is computationally singular: reciprocal condition number = 1.7671e-017 and then I test the determinant of this matrix: 6.341393e-06. In my program, I have a condition block that whether a matrix is invertible like this: if(det(sigma)<1e-7) return NULL; but this seems doesnot work to prevent the singularity when inverting a mat...

...ants with GCC (using fast-math) and we get an answer they view as "wrong", doesn't mean it's a bug of ours and that we need to change to get the same answer as GCC. That's not what our goal of GCC compatibility means to me. >> >> But we do have a switch '-fno-reciprocal-math' that we accept, and even process/implement to some extent. But that implementation has a bug. Fixing that bug so that when a user says '-ffast-math -fno-reciprocal-math', we enable the fast-math transformations but explicitly disable the reciprocal transformations is, in my vi...

> On Nov 16, 2016, at 6:22 PM, Ristow, Warren <warren.ristow at sony.com> wrote: > > > ... except that Warren’s proposal that started this discussion seems to imply that he > > has a use case that requires reciprocals to be turned off separately. > > Just to close this loose end, yes I have a use case. > > Specifically, we have a customer that turns on '‑ffast‑math', but was getting a runtime failure due to the reciprocal-transformation being done. Can you elaborate what kind of runt...

Hi, In relaxed/fast math mode, if we can convert a/b to a * (1/b), we may get more performance when (1) "b" is loop invariant or (2) arch has faster reciprocal instruction (e.g. recipe/recips on ARM) or (3) arch has no vector div, but has vector mul and recip. So ,with this node type, a div node can be converted to a mul and a recip when desired. Then, each arch can further lower the recip node. Even if the arch has no recip support, allowing other...

...d the patterns could be matched directly. -Jim On Sep 20, 2012, at 3:26 PM, Weiming Zhao <weimingz at codeaurora.org> wrote: > Hi, > > In relaxed/fast math mode, if we can convert a/b to a * (1/b), we may get more performance when (1) “b” is loop invariant or (2) arch has faster reciprocal instruction (e.g. recipe/recips on ARM) or (3) arch has no vector div, but has vector mul and recip. > > So ,with this node type, a div node can be converted to a mul and a recip when desired. Then, each arch can further lower the recip node. Even if the arch has no recip support, allowi...

>All that said, I think we (the company I work for, Sony) will have to implement support >for these switches. It comes down to GCC has these switches (e.g., -fno-reciprocal-math >and -fno-associative-math), and they do suppress the transformations for our customers. >They switch to Clang/LLVM, they use the same switches, and it doesn't "work". So as a >practical matter, I think we will support them. Whether the LLVM community in general >...

...1, 84.2469, 83.9371, 73.8800, 89.3921, 89.3900, 86.8921, 85.7036, 85.2664, 83.8700, 90.5493) > scatter.smooth(YMRS_Sum,resid) Warning messages: 1: at -0.02 2: radius 0.0004 3: all data on boundary of neighborhood. make span bigger 4: pseudoinverse used at -0.02 5: neighborhood radius 0.02 6: reciprocal condition number nan 7: zero-width neighborhood. make span bigger 8: There are other near singularities as well. 1 9: at -0.02 10: radius 0.0004 11: all data on boundary of neighborhood. make span bigger 12: pseudoinverse used at -0.02 13: neighborhood radius 0.02 14: reciprocal condition numb...

Point #1 makes sense to me. For point #2, wouldn't that be somewhat orthogonal to the discussion, as it has/needs no knowledge that an IR-level transformation happened? Also, reciprocal-multiply will be the preferred option for many (most) backends if the IR says to do that. But, I suppose some backend might want to be allowed to do the reverse transformation if allowed by fast-math flags in IR, or fast-math mode in selection DAG. On Aug 8, 2013, at 2:23 PM, Chandler Carruth &l...

> On Nov 16, 2016, at 10:04 PM, Ristow, Warren <warren.ristow at sony.com> wrote: > > > Can you elaborate what kind of runtime failure is the reciprocal transformation triggering? > > Yes. It was along the lines of: > > { > float x = a / c; > float y = b / c; > > if (y == 1.0f) { > // do some processing for when 'b' and 'c' are equal > } else { > /...

...39; flag remains, it implicitly re-enables the one being disabled. For example, compiling this test-case: extern void use(float x, float y); void test(float a, float b, float c) { float q1 = a / c; float q2 = b / c; use(q1, q2); } at '-O2 -ffast-math' does a reciprocal-transformation, so only one division is done (as desired with fast-math). Compiling it with: -O2 -ffast-math -fno-reciprocal-math should disable the reciprocal transformations (the flag 'arcp'), but leave all the other fast-math transformations enabled. The current implementation do...

...flag (i.e. allowing reassociation, etc.) will be what is actually needed anyway. I would be inclined to agree with Niolai’s suggestion of combining all the flags related to value safety, except that Warren’s proposal that started this discussion seems to imply that he has a use case that requires reciprocals to be turned off separately. -Andy From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Mehdi Amini via llvm-dev Sent: Wednesday, November 16, 2016 8:55 AM To: Ristow, Warren <warren.ristow at sony.com> Cc: llvm-dev at lists.llvm.org Subject: Re: [llvm-dev] RFC: Consid...