similar to: uniform sampling without replacement algorithm

Splus used a similar method for sampling from "bigdata" objects. One problem was that sample() is used both for creating a sample and for scrambling the order of a vector. Scrambling the order of a big vector wastes time. It would be nice to be able to tell sample() that we don't care about the order. Bill Dunlap TIBCO Software wdunlap tibco.com On Tue, Oct 17, 2017 at 10:55

Let us consider the current uniform sampling without replacement algorithm. It resides in function do_sample in https://svn.r-project.org/R/trunk/src/main/random.c Its complexity is obviously O(n), where the sample is selected from 1...n, since the algorithm has to create a vector of length n. So when the sample size is much lesser than n, the algorithm is not effective. Algorithms with

Dear R forum I have a data.frame as cashflow_df = data.frame(instrument = c("ABC","ABC","ABC","ABC","ABC","ABC","ABC","ABC","ABC","ABC","ABC","ABC","ABC","ABC", "ABC", "PQR", "PQR",

Dear R-users: Recently I found my simulation run into an apparently infinite loop. After a few days of tracing and chasing, I believe it is caused by the built-in unif_rand() and exp_rand() functions: unif_rand() can produce a value of 0 which causes the following part of exp_rand() running into an infinity loop u = unif_rand(); for (;;) { u += u; if (u > 1.0) break;

Suharto, If you're interested in performance with subscripting, you might want to look at pqR (pqR-project.org). It has some substantial performance improvements for subscripting over R Core versions. This is especially true for the current development version of pqR (probably leading to a new release in about a month). You can look at a somewhat-stable snapshot of recent pqR development

Commit-ID: 604d3a0a1570f3478360913c2935ea53d18857e6 Gitweb: http://git.kernel.org/?p=libs/klibc/klibc.git;a=commit;h=604d3a0a1570f3478360913c2935ea53d18857e6 Author: Herbert Xu <herbert at gondor.apana.org.au> AuthorDate: Sat, 19 May 2018 02:39:50 +0800 Committer: Ben Hutchings <ben at decadent.org.uk> CommitDate: Sat, 28 Mar 2020 21:42:55 +0000 [klibc] dash: exec: Stricter

I have released a new, faster, version of R, which I call pqR (for "pretty quick" R), based on R-2.15.0. Among many other improvements, pqR supports automatic use of multiple cores to perform numerical computations in parallel with other numerical computations, and with the interpretive thread. It also implements a true reference counting scheme to reduce the amount of unnecessary

I have rewritten the R parser in the new version of pqR that I recently released (pqR-2015-09-14, at pqR-project.org). The new version of the parser is much cleaner, is faster (sometimes quite substantially faster), has a better interface to the read-eval-print loop, and provides a better basis for future extensions. The deparser has also been substantially revised in pqR, and is better

Dmitriy Selivanov (selivanov.dmitriy at gmail.com) wrote: > Consider following example: > > a = matrix(1:2, nrow = 2, dimnames = list(c("row1", "row2"), c("col1"))) > a[1, ] > # 1 > > It returns *unnamed* vector `1` where I would expect named vector. In fact > it returns named vector when number of columns is > 1. > Same issue applicable

Dear R helpers   After executing the R code, where the last few lines of the code are something like given below.     ## Part of my R code     n = 20   ........ .........   final_output = data.frame(Numbers = numbers, ABC = data1, XYZ = data2, PQR = data3)           write.csv(data.frame(Scenario = paste("Sc_", 1:n, sep = ""), final_output'), 'result.csv', row.names

Dear R helpers   I have some variables say ABC, DEF, PQR, LMN and XYZ. I am choosing any three varaibles at random at a time for my analysis and name these files as input1.csv, input2.csv and input3.csv. So if I choose variables say ABC, DEF and PQR, I am passing the specifications of these variables to input1.csv, input2.csv and input3.csv respectively.   This means in another case even if I

A new version of pqR is now available at pqR-project.org, which fixes several bugs that are also present in the latest R Core patch release (r66002). A number of bugs found previously during pqR development are also unfixed in the latest R Core release. Here is the list of these bugs that are unfixed in r66002 (including documentation deficiencies), taken from the pqR bug fix and documentation

I have two questions about using a user-defined random number generator (RNG) with the standalone Rmath library. The default RNG with the standalone Rmath library is the Marsaglia-multicarry generator, which has poor properties. The "R Installation and Administration" manual, in the section "The standalone Rmath library", states that: ``` A little care is needed to use the

Dear R Forum, I have a data.frame as df = data.frame(date = c("2013-04-15", "2013-04-14", "2013-04-13", "2013-04-12", "2013-04-11"), ABC_f = c(62.80739769,81.04525895,84.65712455,12.78237251,57.61345256), LMN_d = c(21.16794336,54.6580401,63.8923307,87.59880367,87.07693716), XYZ_p = c(55.8885464,94.1358684,84.0089114,98.99746696,64.71083712),

Along with getting pqR to work on Windows, I've also been testing it in the context of embedded R, and in the process have found some problems with the examples given of embedded R use. One problem can be seen in R_ReplDLLinit, in src/main/main.c: void R_ReplDLLinit(void) { SETJMP(R_Toplevel.cjmpbuf); R_GlobalContext = R_ToplevelContext = R_SessionContext = &R_Toplevel;

> From: "Cohn, Robert S" <robert.s.cohn at intel.com> > > I am using R to multiply some large (30k x 30k double) matrices on a > 64 core machine (xeon phi). I added some timers to > src/main/array.c to see where the time is going. All of the time is > being spent in the matprod function, most of that time is spent in > dgemm. 15 seconds is in matprod in

Dear Sirs. I'm trying to make a Backup System using SAMBA. The purpose is make backup of some directory of Windows 9x machines, like Office Documents, E-mails directory, etc. If I make one software that "select" and backup certain directories, it will be good. There are ~200 machines with Windows 9x, in 5 C class network: 1 - xyz.pqr.8.abc 2 - xyz.pqr.9.abc 3 - xyz.pqr.10.abc 4 -

There are websites using python to convert a pdb to a pqr. I was wondering if there is a simpler way to do it. We have a protein in pdb format, and want to convert that to a pqr file so that the program apbs can open it. We want to accomplish this conversion in R. Thank you for your help. -- View this message in context: http://n4.nabble.com/Converting-pdb-to-pqr-tp1475426p1475426.html Sent

> Henrik Bengtsson: > > I'm looking for a way to get the length of an object 'x' as given by > base data type without dispatching on class. The performance improvement you're looking for is implemented in the latest version of pqR (pqR-2016-10-24, see pqR-project.org), along with corresponding improvements in several other circumstances where unclass(x) does not

On 19/09/2018 12:23 PM, Philip B. Stark wrote: > No, the 2nd call only happens when m > 2**31. Here's the code: Yes, you're right. Sorry! So the ratio really does come close to 2. However, the difference in probabilities between outcomes is still at most 2^-32 when m is less than that cutoff. That's not feasible to detect; the only detectable difference would happen if