similar to: Error propagation

Displaying 20 results from an estimated 20000 matches similar to: "Error propagation"

2010 Sep 09
5
Calculating with tolerances (error propagation)
Hello Bernardo, --------- If I understood your problem this script solve your problem: q<-0.15 + c(-.1,0,.1) h<-10 + c(-.1,0,.1) 5*q*h [1] 2.475 7.500 12.625 --------- OK, this solves the simple example. But what if the example is not that simple. E.g. P = 5 * q/h Here, to get the maximum tolerances for P, we need to divide the maximum value for q by the minimum value for h, and
2008 Mar 25
1
Error propagation
Dear R-helpers, I´m in the context of writing a general function for error propagation in R. There are somehow a few questions I would like to ask (discuss), as my statistical knowledge is somewhat restricted. Below is the function I wrote, the questions are marked. Many thanks in advance. propagate <- function(expr, varList, type = c("stat", "raw"), cov = TRUE) {
2013 Dec 11
2
[LLVMdev] Float undef value propagation
You are right some cases would definitely not be right like undef + Nan -> undef. For 2.0f case I'm not sure either if any bits could be known. It seems that in general fadd( float undef, float %1) -> float %1 should always be safe and I just checked with latest code this doesn't happen. Do you think the right solution would be to add such optimization? Is there any reason why we
2017 Jun 15
2
LLC does not do proper copy propagation (or copy coalescing)
Hello. Could you please tell me how can I optimize with the back end (llc) the following piece of assembly code generated by llc: // NOTE: my processor accepts loops in the form of REPEAT(num_times)..END_REPEAT R0 = ... REPEAT(256) R5 = R0; // basically unnecessary reg. copy REPEAT(256) R10 = LS[R4]; R2 = LS[R5]; R4 =
2001 Aug 28
1
Subsetting simulation output
Does anyone understand this? I have a long vector parlist containing values of 138 parameters in 100 simulations. The factor parno is defined by trys <- 100 sim <- gl(trys,138) parno <- gl(138,1,trys*138) I want to extract and compare results for related groups of parameters but I get inconsistent results: > length(parlist[parno==37:42]) [1] 600 >
2013 Mar 08
4
Substitute value
Hi, I have a large data frame and within this there is one column which contains individual codes (eg. 1.1234.2a.2). I am splitting these codes into their 4 components using strsplit (eg. "1", "1234", "2a", "2"). However there are some individual codes which do not have a last component (eg. 2.4356.3b. ), I want to give these codes a "1" as their
2004 Aug 25
1
brlr function
Hi, I'm trying the brlr function in a penalized logistic regression function. However, I am not sure why I am encountering errors. I hope to seek your advice here. (output below) Thank you! Your help is truly appreciated. Min-Han #No error here, the glm seems to work fine >
2008 Jul 14
2
Backslash in sub pattern?
Dear guRus, I am trying to replace "~" by "$\sim$" for TeX. However, I can't get the backslash to work. I would like to turn "DV~IV" into "DV$\sim$IV". sub("~","$\sim$","DV~IV") => "DV$sim$IV" sub("~","$\\sim$","DV~IV") => "DV$sim$IV"
2013 Jun 25
1
[LLVMdev] ldexp constant propagation
Hi, I have the C program below, which contains a mathematical expression. C code: ====== void ControlledRotationPiMinus(int target, int control, int j) { ControlledPhase(target,control,-PI/(2*pow(2,j))); } int main() { .. int b = 3; for (int j=1; j < b; j++) ControlledRotationPiMinus(target, control, j); .. } Here is what I am doing: The function ControlledRotationPiMinus is called
2012 Apr 12
2
[LLVMdev] Question::ARM simulation and cross compilation.
Hello, I'm trying to evaluate the performance improvement of instruction scheduling on one of the inorder ARM processor, I was looking for ARM simulator and I found two (Simplescalar/ARM and SimIt-ARM) The code generated using llvm-2.9 and llvm-gcc and gcc 3.2. I used these command : $ llvm-gcc -O3 -o test1.bc -c --emit-llvm test1.c $ llc -O3 -o test1.s -march=arm test1.bc -mcpu=strongarm110
2010 Oct 20
3
Plot help
Dear List, I am relatively new to R and am trying to create more attractive plots than excel can manage! I have looked through the various programmes ggplot, lattice, hmisc etc but my case seems to be not metnioned, maybe it is but i have not noticed - if this is the case i apologise.
2009 Jul 15
1
Simulation code error
Dear List, I have some problem with my simulation code. Here is output from R: > sim.sp <- function(data,CM,n,N) + { + C <- matrix(rep(NA,N),ncol=1) + for(i in 1:N) + { + j <- n + xx <- which(colSums(CM[j,])==1) + V <- names(xx) + V <- paste(V, collapse="+") + V <- paste("SBA~", V) + rd <- round(nrow(data)*(2/3)) + d <-
2013 Dec 10
0
[LLVMdev] Float undef value propagation
On 12/9/13 2:13 PM, Raoux, Thomas F wrote: > > Constant propagation pass generates constant expression when undef is > used in float instructions instead of propagating the undef value. > > ; Function Attrs: nounwind > > define float @_Z1fv() #0 { > > entry: > > %add = fadd fast float undef, 2.000000e+00 > > ret float %add > > } > > Becomes:
2005 Apr 13
1
i param in "for" loop does not takes zeros?
Hi all Is there any reason why the parameter i in a "for" loop ignores a value of zero? For example sim=c() p=.2 for(i in 0:5) {sim[i]=dbinom(i,5,p) } sim [1] 0.40960 0.20480 0.05120 0.00640 0.00032 In this example the quantile i= 0 was ignored since dbinom(0,5,p) [1] 0.32768 The same behaviour occurs if I use a while loop to perform the same calculation: sim=c() p=.2 i=0
2023 Feb 23
2
Possible NA Propagation Failure in RISC-V64 CPU?
Hi all, I am currently compiling R to RISC-V64 CPU and I think I have discovered a NA propagation failure. How R implements NA (not available) and NaN (not-a-number) is explained in detail here: https://stat.ethz.ch/pipermail/r-devel/2014-February/068380.html. In short, according to my understanding of R's convention, any calculation involving NA but no NaN should result in NA (called NA
2019 May 15
1
domain still running although snapshot-file is deleted !?!
Hi, i have a strange situation: A domain is still running where domblklist points to a snapshot file and also dumpxml says the current drive is that snapshot file. But the file has been deleted hours ago. And the domain is still running. I can login via ssh, the database and the webserver are still running, domain is performant. How can that be ? Also lsof shows that the file is deleted:
2006 Jan 13
1
Variance-covariance by factor
Dear all, I have a data frame with one factor and four numeric variables and wish to obtain the var-cor matrix separately by factor. I tried by() and sapply() but getting nowhere. I understand this can be done by subsetting the dataframe, but there should have some sleek ways of doing it. Here is a simulated dataframe; s <- rep(c("A","B","C"), c(25,22,18)) d
2006 Sep 20
4
Calculating mean together with split
Hi I have a table called npl containing results of simulations. It contains about 19000 entries and the structure looks like this: NoPlants sim run year DensPlants 1 6 lng_cs99_renosterbos 1 4 0.00192 . . . it has 43 different entries for sim and year goes from 1 to 100, and run from 1 to 5. I would like to calculate the mean of DensPlants for each
2013 Dec 09
4
[LLVMdev] Float undef value propagation
Constant propagation pass generates constant expression when undef is used in float instructions instead of propagating the undef value. ; Function Attrs: nounwind define float @_Z1fv() #0 { entry: %add = fadd fast float undef, 2.000000e+00 ret float %add } Becomes: ; Function Attrs: nounwind define float @_Z1fv() #0 { entry: ret float fadd (float undef, float 2.000000e+00) } Is it safe
2008 Mar 05
2
simulating the anova
I have been trying to figure out how to run a simple simulation of the ANOVA and I'm coming up just a bit short. The code I've got is: cohen.f = .25 groups = 4 between.var = 19 within.var = between.var / cohen.f ^ 2 n = 500 sim.means = rnorm(n = groups, mean = 0, sd = sqrt(between.var)) sim.data = lapply(sim.means, function(mean) rnorm(n = n, mean = mean, sd = sqrt(within.var)))