search for: surrogate

I have a question on generating multivariate time series surrogates using the "surrogates" function in the RTisean library. The surrogate data matrices are always much shorter than the input matrices. FYI, I'm using R version 2.12.2 on Windows XP RTisean library v 3.0.14 Tisean algorithms v 3.0.13 Creating a surrogate univariate time series...

Dear R, Short verse of the question: Is there R code which will calculate surrogate splits and/or delta impurity for decision trees at each node? Long Version: I have local, legacy code which I use to calculate my decision trees. I would like to switch to R, but as I understand it surrogate splits are not implemented. Surrogate splits and feature ranking are described in Breim...

...able3 Sample1 Sample 2 Sample 3 Sample 4 Sample 5 after performing the analysis (MRT) I asked for the summary but I didn't get the surrogate splits, only the information for the primary splits (the secuence of commands I used is pasted at the end of the email). I would like to know how to get the information about the surrogate splits, please let me know any ideas. Thank you very much in advanced, Looking forward to hearing from you,...

Dear R-help, I would like to compute the variance for the proportion of treatment effect by a surrogate in a survival model (Lin, Fleming, and De Gruttola 1997 in Statistics in Medicine). The paper mentioned that the covariance matrix matches that of the covariance matrix estimator for the marginal hazard modelling of multiple events data (Wei, Lin, and Weissfeld 1989 JASA), and is implemented in Li...

As per `?intToUtf8`, and in the comments to `valid_utf8`[1], R intends to prevent illegal UTF-8 such as UTF-8 encoded UTF-16 surrogate pairs.? `R_nchar`, invoked via `base::nchar`, explicitly validates UTF-8 strings[2], but allows the surrogate: ??? > Encoding('\ud800') ??? [1] "UTF-8" ??? > nchar('\ud800')? // should be an error ??? [1] 1 The problem manifests on systems where `char` is signed.?...

R helpers, I would like to know if it is possible that the last version of R is not giving the surrogate splits when you perform a Multivariate regression tree analysis? I installed the programm in different computers and i run the some matrix and it didn't gave me this information. With a previus version R 2.1.1. I do get the information for the surrogates. Please let me know how to get the surro...

Dear R-help, I'm applying the surrogate Poisson glm, by following Venables & Ripley (7.3 pp238-42). >overall_cbind(expand.grid(treatment=c("Pema","control"),age=c("young","adult","old"),repair=c("excellent","good","poor")),Fr=c(8,0,7,1,2,0,2,7,1,4,7,...

...+ ( ) ) / \ ( (_/ \_) > -----Original Message----- > From: Thomas Lumley [mailto:thomas at biostat.washington.edu] > Sent: 4. maj 1999 16:00 > To: Simon Bond > Cc: r-help at stat.math.ethz.ch > Subject: Re: [R] surrogate poisson models > > > On Tue, 4 May 1999, Simon Bond wrote: > > > > > Call: > > glm(formula = terms(Fr ~ treatment * age + (treatment + age) * > > repair, keep.order = T), family = poisson, data = overall) > > > > > > > Coefficien...

Hello all, I am working on building a web store with RoR. The company has many locations. All the stock/order information is processed through the same site. Here is my question. How would you handle the multiple warehouse problem with Rails? How would you keep track of the information in multiple warehouses? Thank you for your help, PV -- Posted via http://www.ruby-forum.com/.

...i = 0 then Buffer.add_char outbuf (Char.chr (c lor first)) + else if i > 0 then ( + loop (i-1) (c lsr 6); + Buffer.add_char outbuf (Char.chr ((c land 0x3f) lor 0x80)) + ) + in + loop (len-1) c + in + + (* Loop over the input UTF16-LE characters. *) + let is_high_surrogate c = c >= 0xd800 && c < 0xdc00 + and is_low_surrogate c = c >= 0xdc00 && c < 0xe000 + and surrogate_value highc lowc = + 0x1_0000 + (highc - 0xd800) * 0x400 + lowc - 0xdc00 + in + + let len = String.length instr in + let rec loop i = + if i+1 >= len then ()...

...2325, MSE=44176.93 left son=2 (81 obs) right son=3 (147 obs) Primary splits: pat.karno < 75 to the left, improve=0.03661157, (3 missing) ph.ecog < 1.5 to the right, improve=0.03620793, (1 missing) age < 75.5 to the right, improve=0.01606491, (0 missing) Surrogate splits: ph.ecog < 1.5 to the right, agree=0.787, adj=0.392, (3 split) age < 72.5 to the right, agree=0.680, adj=0.089, (0 split) In Breiman, Friedman, Olshen, & Stone, the canonical CART book, the pat.karno variable would get .0366 "points" for this split, ph.e...

I have a table that is to hold all ISO 639 language codes: alpha3t, alpha3b, alpha2, that bunch. It also (indirectly) holds language names, but that''s off-topic. alpha3t is the primary key, so I''ve told Active Record about this by saying set_primary_key "alpha3t" within the Language model. (Don''t try to call your models things like ISO639 (won''t work

...and that one may impute missing values using rfImpute or some other method, but I would like to avoid doing that.) If this functionality were available, then when the trees are being constructed and when subsequent data are put through the forest, one would also specify an argument for the use of surrogate rules, just like in rpart. I realize this question is very specific to randomForest, as opposed to R in general, but any comments are appreciated. I suppose I am looking for someone to say "It's not appropriate, and here's why ..." or "Good idea. Please implement and post y...

...) ????? Hsa.8147? < 1696.23? to the right, improve=14.46790, (0 missing) ????? Hsa.37937 < 379.39?? to the right, improve=13.75358, (0 missing) ????? Hsa.692.2 < 842.305? to the right, improve=12.38710, (0 missing) ????? Hsa.1832? < 735.805? to the right, improve=11.90495, (0 missing) ? Surrogate splits: ????? Hsa.692.2 < 1086.655 to the right, agree=0.903, adj=0.571, (0 split) ????? Hsa.3306? < 170.515? to the left,? agree=0.887, adj=0.500, (0 split) ????? Hsa.601?? < 88.065?? to the left,? agree=0.887, adj=0.500, (0 split) ????? Hsa.692?? < 1251.99? to the right, agree=0.871,...

Hi all, I started playing a couple days ago with Rails and it find it very interesting. But I''m a bit stuck with making it work with a concatenated primary key. I want to use my own names for the DB fields and I''m using SQL Server 2005. My tables look roughly like this: CREATE TABLE USERS ( USR_ID VARCHAR(25) NOT NULL PRIMARY KEY, USR_PASS VARCHAR(25) ) CREATE TABLE

..., I’m trying to understand how correlated predictors impact the Relative Importance measure in Stochastic Boosting Trees (J. Friedman). As Friedman described “ …with single decision trees (referring to Brieman’s CART algorithm), the relative importance measure is augmented by a strategy involving surrogate splits intended to uncover the masking of influential variables by others highly associated with them. This strategy is most helpful with single decision trees where the opportunity for variables to participate in splitting is limited by the size of the tree. In the context of Boosting, however, th...

Hi everyone, I've noticed new behavior in `regexpr(..., perl = TRUE)` on Windows with R4.0 and above with Unicode characters. Here's a minimal example where I'd expect to see a start value of `5` (as R 3.6.2 and below gives), but R 4.0.0 (and R 4.0.1) now returns: ``` > regexpr("b", "foo\U0001F937bar", perl = TRUE) #> [1] 6 #>

Dear r-help, I am trying to build a new function (to process rpart objects) that will output matrix that has a row for each node and a column for each feature. With each entry in the table is a numerical property at that node for that feature (e.g. surrogate split agreement, improvement). My current trouble is that the only clue to the identity of the feature is stored as the *name* of the feature. Whereas a table is indexed by *number*. I have a list of sorted names, but I am having trouble translating a name into a number. If this where perl the...

Have been looking into using rails but am finding the "Composite Primary Keys are Bad" thing a tad disturbing (to put it mildly). I have been working with RDBMS systems for over fifteen years and this is the first time I have herd the idea questioned. I have cone across using surrogate keys which mirror the composite key for performance reasons in VERY big databases but I have never herd the idea questioned from a logical database design point of view. Apart from it being easier in rails to use non composite keys has anyone got any other good reasons not to use them. As far as...

...Grand Rapids, Michigan search criteria is less likely to include documents from Minnesota and Ohio. However, two aspects of this approach bother me. First, the creation and maintenance of term prefixes for each level of the hierarchy feels wrong. Second, the concatenation of values seems like a surrogate for using weights. So, what is the best way to represent a hierarchy with term prefixes? Note, I posted this question to stackoverflow here: http://stackoverflow.com/questions/7585948/what-is-the-best-way-to-represent-a- category-hierarchy-using-term-prefixes-in-xa I didn't get any response...