search for: pedagogically

Hi I am currently (for pedagogical purposes) writing a simple numerical analysis library in R. I have come unstuck when writing a simple Newton-Raphson implementation, that looks like this: f <- function(x) { 2*cos(x)^2 + 3*sin(x) + 0.5 } root <- newton(f, tol=0.0001, N=20, a=1) My issue is calculating the symbolic derivative of f() inside the newton() function. I cant seem to get R to

Folks, I put up a brief note describing my naive attempts to compute Goldbach partitions, starting with a brute-force approach and refining progressively. http://jostamon.blogspot.com/2009/02/goldbachs-comet.html I'd welcome your suggestions on improvements, alternatives, other optimisations, esp. to do with space vs time tradeoffs. Is this an example interesting enough for

Dear R users, I have a dataset with two variables: $esan - a grouping factor with 8 levels and $reus. I'd like to do wilcox.test on this dataset as sugested Weiwei here: https://stat.ethz.ch/pipermail/r-help/2007-July/136627.html. I tried to adapt his recommendation but no succes. Can anyone help me? Regards, Iurie Malai, Senior Lecturer Department of Psychology Faculty of Psychology and

Dear all, I have written a small set of functions for drawing graphical representations of R objects and evaluations of R expressions. It is mainly intended for pedagogical purposes. Here are some samples: http://panini.u-paris10.fr/~sloiseau/sampleGraphics.pdf The idea is to use some graphical conventions in order to make clear the abstract syntax and to explain function, extraction,

I want to run Shapiro-Wilk test for each variable in my dataset, each grouped by variable groupFactor. I have these working commands: > data.n<-names(data) # put names into a vector called data.n > by(eval(parse(text=(paste("data",data.n[3],sep="$")))), data$factor, shapiro.test) #run shapiro.test but I must to change the variable number manualy. How to automate

For a pedagogical purpose, I was trying to show how the formula for a simple regression line (~1+x) could be crossed with a factor (~1:group + x:group) to fit separate regressions by group. For example: set.seed(201108) dat <- data.frame(x=1:15, y=1:15+rnorm(15), group = sample(c('A','B'), size=15, replace=TRUE)) m1 <- lm(y~ 1 + x, data=dat)

Hi, I have a data set: > Dataset X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 X16 X17 1 user1 m 22 19 28 24 12 18 9 7 4 5 4 7 5 7 9 2 user2 f 25 19 23 18 18 15 6 8 6 6 7 10 7 7 7 3 user3 f 28 21 24 18 15 12 10 6 7 9 5 10 5 9 5 4 user4 f 26 19 26 21 12 18 6 6 5 1 3 8 6 5 6 5 user5 m 21 22 26 18 9 6 4 6 1

Howdy All, I''ve a bit of a strange problem here. I have a filesystem with one snapshot that simply refuses to be destroyed. The snapshots just prior to it and just after it were destroyed without problem. While running the zfs destroy command on this particular snapshot, the server becomes more-or-less hung. It''s pingable but will not open a new shell (local or via ssh) however

Dear list users How is it possible to visualise both a linear trend line and a quadratic trend line on a plot of two variables? Here my almost working exsample. data(Duncan) attach(Duncan) plot(prestige ~ income) abline(lm(prestige ~ income), col=2, lwd=2) Now I would like to add yet another trend line, but this time a quadratic one. So I have two trend lines. One linear trend line

Hi, Is there a simple way of rolling back to a specific TXG of a volume to recover from such a situation? Many thanks, Przem -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20110627/9b1c5a85/attachment.html>

A recent paper from Google Labs, interesting in many respects, not the least the exclusive use of R for data analysis and graphics (alas not cited in the approved manner): http://labs.google.com/papers/disk_failures.pdf Perhaps some of the eminences grises of the R Foundation could prevail upon Google to make some the data reported in the paper available for inclusion in an R library or two, for

Hi, All! To calculate Levene's Test for Homogeneity of Variance I use R Commander, and this is the output: > levene.test(Dataset$age, Dataset$sex) Levene's Test for Homogeneity of Variance Df F value Pr(>F) group 1 0.8739 0.3567 33 I am not sure what means "Pr(>F)"? Can anyone explain/translate this? Regards, Iurie Malai Department of Psychology and

How to make a launcher for Rattle? Regards, Iurie Malai Moldova Pedagogical State University [[alternative HTML version deleted]]

Hi all We have a 100kVA GE LP Series UPS. I can't find this series in the HCL, but other GE UPSes are listed. Would it be possible to somehow use NUT with this UPS? -- Vennlige hilsener / Best regards roy -- Roy Sigurd Karlsbakk (+47) 98013356 roy at karlsbakk.net http://blogg.karlsbakk.net/ GPG Public key: http://karlsbakk.net/roysigurdkarlsbakk.pubkey.txt -- I all pedagogikk er det

Hi all I have installed a new server with 77 2TB drives in 11 7-drive RAIDz2 VDEVs, all on WD Black drives. Now, it seems two of these drives were bad, one of them had a bunch of errors, the other was very slow. After zfs offlining these and then zfs replacing them with online spares, resilver ended and I thought it''d be ok. Appearently not. Albeit the resilver succeeds, the pool status

Hi all Trying to setup dovecot with mysql and postfix, I have configured it as given below. thecot user has the dovecot group as primary, and is also a member of mail and dovecot-users. Still, it can't setgid to dovecot-users. I tried changing the shell for the dovecot user to something useful and chmod'ing a file to dovecot-users, and it work well. Still, no mail comes through

Hi all Has anyone done any testing with dedup with OI? On opensolaris there is a nifty "feature" that allows the system to hang for hours or days if attempting to delete a dataset on a deduped pool. This is said to be fixed, but I haven''t seen that myself, so I''m just wondering... I''ll get a 10TB test box released for testing OI in a few weeks, but before

The public connection API is defined in https://github.com/wch/r-source/blob/trunk/src/include/R_ext/Connections.h I'm not sure of a good pedagogic example; people who want to write their own connections usually want to do so for complicated reasons! This is my own abandoned attempt

I want to use the grplasso package on a data set where I want to fit a linear model.? My interest is in identifying significant?beta coefficients.? The documentation is a bit cryptic so I'd appreciate some help. ? I know this is a strategy for large numbers of variables but consider a simple case for pedagogical puposes.? Say I have?two 3 category predictors (2 dummies each), a binary

Hi I''m running OpenSolaris 148 on a few boxes, and newer boxes are getting installed as we speak. What would you suggest for a good SLOG device? It seems some new PCI-E-based ones are hitting the market, but will those require special drivers? Cost is obviously alsoo an issue here.... Vennlige hilsener / Best regards roy -- Roy Sigurd Karlsbakk (+47) 97542685 roy at karlsbakk.net