Re: [R] Matrix question: obtaining the square root of a positive definite matrix?

On Wed, 24 Jan 2007, gallon li wrote: I want to compute B=A^{1/2} such that B*B=A. According to your subject line A is positive definite and hence symmetric? The usual definition of a matrix square root involves a transpose, e.g. B'B = A. There are many square roots: were you looking for a

Re: [R] Vector to Matrix transformation

How to suppress the recycling of items in a matrix..instead NA can be filled. -Original Message- From: Chuck Cleland [mailto:[EMAIL PROTECTED] Sent: Tuesday, January 23, 2007 8:00 PM To: Shubha Vishwanath Karanth Cc: r-help@stat.math.ethz.ch Subject: Re: [R] Vector to Matrix

[R] Checking for the existence of an R object

Hi, Is there any way to check whether an R object exists or not? Say example: a data frame. Thanks, Shubha [[alternative HTML version deleted]] __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help

Re: [R] Checking for the existence of an R object

see: ?exists HTH. On 1/24/07, Shubha Vishwanath Karanth [EMAIL PROTECTED] wrote: Hi, Is there any way to check whether an R object exists or not? Say example: a data frame. Thanks, Shubha [[alternative HTML version deleted]] __

Re: [R] Checking for the existence of an R object

Thanks all of you... -Original Message- From: talepanda [mailto:[EMAIL PROTECTED] Sent: Wednesday, January 24, 2007 2:10 PM To: Shubha Vishwanath Karanth Cc: r-help@stat.math.ethz.ch Subject: Re: [R] Checking for the existence of an R object see: ?exists HTH. On 1/24/07, Shubha

Re: [R] Matrix question: obtaining the square root of a positive definite matrix?

Prof Brian Ripley wrote: On Wed, 24 Jan 2007, gallon li wrote: I want to compute B=A^{1/2} such that B*B=A. According to your subject line A is positive definite and hence symmetric? The usual definition of a matrix square root involves a transpose, e.g. B'B = A. There are

Re: [R] Vector to Matrix transformation

non-elegant solution: matrix(c(V1,rep(NA,-length(V1)%%5)),nrow=5) HTH. On 1/24/07, Shubha Vishwanath Karanth [EMAIL PROTECTED] wrote: How to suppress the recycling of items in a matrix..instead NA can be filled. -Original Message- From: Chuck Cleland [mailto:[EMAIL PROTECTED]

[R] Date variable

Dear R users, I did following with a date variable library(date) date = 03/11/05 date = as.Date(date, format=%m/%d/%y) date [1] 2005-03-11 s = vector(length=3) s[1] = date s[1] [1] 12853 But here I got s[1] as 12853. But this is not that I want. I need s[1] as original date.

Re: [R] Date variable

For Date class, *original* (that is, contents in memory) is 12853, and 2005-03-11 is one expression of the original. So you have to convert from the original to the charecter expression as follows. s[1]-format(date) s [1] 2005-03-11 FALSE FALSE s[1]-as.character(date) s [1] 2005-03-11

[R] Matrix subsetting {was ... vectorized nested loop...}

Hi Jose, I'm answering your second batch of questions, since Chuck Berry has already well done so with the first one Jose == Jose Quesada [EMAIL PROTECTED] on Tue, 23 Jan 2007 21:46:27 +0100 writes: [] Jose # example Jose library(Matrix) Jose x = as(x,CsparseMatrix)

[R] how to change the dataframe labels' ?

I import a dataframe composed by 2 variables and 14000 cases. Now I need the labels of the cases sorted by the second variable V2, but if I sort the dataframe according to the second variable: mydataframe- mydataframe[order(mydataframe$V2),] I notice that the labels are always the same (that is,

Re: [R] solving a structural equation model using sem or other package

This is an extract from the sem help page, which deals with your situation: S covariance matrix among observed variables; may be input as a symmetric matrix, or as a lower- or upper-triangular matrix. S may also be a raw (i.e., ``uncorrected'') moment matrix — that is, a

Re: [R] how to change the dataframe labels' ?

rownames()- is what you want. dat-data.frame(V1=sample(10),V2=sample(10)) dat V1 V2 1 2 5 2 3 8 3 8 4 4 9 6 5 6 2 6 5 7 7 10 3 8 4 9 9 1 10 10 7 1 dat-dat[order(dat$V2),] dat V1 V2 10 7 1 5 6 2 7 10 3 3 8 4 1 2 5 4 9 6 6 5 7 2 3 8 8 4

Re: [R] How to generate 'minor' ticks in lattice (qqmath)

Dear Gabor! thanks for your hints; as a side-effect I learned a lot about lattice. The working example is: library(lattice) library(grid) numy - 100 y - runif(numy,min=0,max=1) sig - 0.05 numsig - length(which(ysig)) Lower - 0 Upper - 1 MajorInterval - 5 # interval for major ticks

Re: [R] how to change the dataframe labels' ?

Sorry, no: row.names-() is what you want. rownames for matrices (and arrays) row.names for data frames. Using them the other way round usually works but can be very inefficient. From R-devel (where the worst inefficiencies are circumvented) The extractor functions try to do something

[R] Conversion of column matrix into a vector without duplicates

Hi R, I have a matrix A, A= [,1] [,2] [1,] a u [2,] b v [3,] c x [4,] d x [5,] e x I want to put the 2nd column of this matrix in a vector without duplicates. i.e., my vector v should be (u, v, x), whose length is 3. Can anybody help me on this?

[R] Capturing output from external executables, in windows

Hi, Any help on the following would be much appreciated I wish to capture the output (currently going to console) from an external executable. The executable is successfully run using system(program -switch ) and the output printed to the DOS console. How do I capture this output? I

Re: [R] Conversion of column matrix into a vector without duplicates

you need: unique(A[, 2]) Best, Dimitris Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/(0)16/336899 Fax: +32/(0)16/337015 Web: http://med.kuleuven.be/biostat/

Re: [R] Conversion of column matrix into a vector without duplicates

?unique unique(A[, 2]) ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Reseach Institute for Nature and Forest Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and

Re: [R] Conversion of column matrix into a vector without duplicates

Shubha Vishwanath Karanth wrote: Hi R, I have a matrix A, A= [,1] [,2] [1,] a u [2,] b v [3,] c x [4,] d x [5,] e x I want to put the 2nd column of this matrix in a vector without duplicates. i.e., my vector v should be (u, v, x), whose length

Re: [R] Date variable

You don't appear to be using any functionality from the date package but are using the Date class which is built into the base of R. Assuming: d - as.Date(03/11/05, %m/%d/%y) # and try one of these: d3 - structure(rep(NA, 3), class = Date) d3[1] - d d3 # or d3 - rep(d, 3) + NA d3[1] - d d3 #

[R] Logistic regression model + precision/recall

Hi, I am using logistic regression model named lrm(Design) Rite now I was using Area Under Curve (AUC) for testing my model. But, now I have to calculate precision/recall of the model on test cases. For lrm, precision and recal would be simply defined with the help of 2 terms below: True

Re: [R] How to generate 'minor' ticks in lattice (qqmath)

I think you have a stray trellis.focus statement (just before the qqmath statement). Probably a cut and paste problem. Regards. On 1/24/07, Helmut Schütz [EMAIL PROTECTED] wrote: Dear Gabor! thanks for your hints; as a side-effect I learned a lot about lattice. The working example is:

Re: [R] Capturing output from external executables, in windows

You can try: system(command, show.output.on.console=TRUE) On 24/01/07, Darren Obbard [EMAIL PROTECTED] wrote: Hi, Any help on the following would be much appreciated I wish to capture the output (currently going to console) from an external executable. The executable is successfully

Re: [R] [fixed] vectorized nested loop: apply a function that takes two rows

Thanks Charles, Martin, Substantial improvement with the vectorized solution. Here is a quick benchmark: # The loop-based solution: nestedCos = function (x) { if (is(x, Matrix) ) { cos = array(NA, c(ncol(x), ncol(x))) for (i in 2:ncol(x)) {

Re: [R] how to change the dataframe labels' ?

I did not know the fact. Thanks for useful information. On 1/24/07, Prof Brian Ripley [EMAIL PROTECTED] wrote: Sorry, no: row.names-() is what you want. rownames for matrices (and arrays) row.names for data frames. Using them the other way round usually works but can be very inefficient.

[R] Problem with ordered probit model in MASS

Dear all, I got this message, while using the polr function in MASS EQ-as.formula(dep~fpta+tcdv+cdta+cmta+prcd+patc+lactifs+excta) Estim-polr(EQ,don, subset=(cote!=0),method=probit,na.action=na.omit) Error in polr(EQ, don, subset = (cote != 0), method = probit, na.action = na.omit) :

[R] keep track of selected observations over time

Dear all, Attached is a description of my data, graph and the problem which I need help with. Hope you have time to open the file and help me out. Many thanks, Jenny - __

Re: [R] Logistic regression model + precision/recall

nitin jindal wrote: Hi, I am using logistic regression model named lrm(Design) Rite now I was using Area Under Curve (AUC) for testing my model. But, now I have to calculate precision/recall of the model on test cases. For lrm, precision and recal would be simply defined with the help of

Re: [R] How to generate 'minor' ticks in lattice (qqmath)

Yes thanks, just a kind of 'left-over' ;-) Regards, Helmut Gabor Grothendieck wrote: I think you have a stray trellis.focus statement (just before the qqmath statement). Probably a cut and paste problem. Regards. trellis.focus(panel, 1, 1, clip.off = TRUE) -- Helmut Schütz BEBAC

Re: [R] Capturing output from external executables, in windows

On 1/24/2007 8:22 AM, Darren Obbard wrote: Hi, Any help on the following would be much appreciated I wish to capture the output (currently going to console) from an external executable. The executable is successfully run using system(program -switch ) and the output printed

Re: [R] [fixed] vectorized nested loop: apply a function that takes two rows

Jose Quesada wrote: Thanks Charles, Martin, Substantial improvement with the vectorized solution. Here is a quick benchmark: # The loop-based solution: nestedCos = function (x) { if (is(x, Matrix) ) { cos = array(NA, c(ncol(x), ncol(x))) for (i in

[R] double integral with C

Hi all, This is more a C querie rather than a R one: I'm writing a C code passing a function F to adapt fortran subroutine. I need to integrate over two variables of F, call them x1 and x2. Then I call the C code in R to optimize the integrated F function. for example F could be defined as

Re: [R] Capturing output from external executables, in windows

Is this for RGui under Windows? I will assume so (but 'in windows' is not unambiguous, and there are alternative front-ends like Rterm). Have you consulted the help page for system()?: this is precisely what 'show.output.on.console' is for. You cannot redirect in system (it does say so on the

Re: [R] Logistic regression model + precision/recall

On 1/24/07, Frank E Harrell Jr [EMAIL PROTECTED] wrote: Why 0.5? The probability has to adjusted based on some hit and trials. I just mentioned it as an example Those are improper scoring rules that can be tricked. If the outcome is rare (say 0.02 incidence) you could just predict that no

Re: [R] Problem with ordered probit model in MASS

On Wed, 24 Jan 2007, justin bem wrote: (Again: this is a duplicate post.) Dear all, I got this message, while using the polr function in MASS EQ-as.formula(dep~fpta+tcdv+cdta+cmta+prcd+patc+lactifs+excta) Estim-polr(EQ,don, subset=(cote!=0),method=probit,na.action=na.omit) Error in

Re: [R] Logistic regression model + precision/recall

nitin jindal wrote: On 1/24/07, Frank E Harrell Jr [EMAIL PROTECTED] wrote: Why 0.5? The probability has to adjusted based on some hit and trials. I just mentioned it as an example Using a cutoff is not a good idea unless the utility (loss) function is discontinuous and is the same for

Re: [R] Logistic regression model + precision/recall

On 1/24/07, Frank E Harrell Jr [EMAIL PROTECTED] wrote: nitin jindal wrote: Using a cutoff is not a good idea unless the utility (loss) function is discontinuous and is the same for every subject (in the medical field utilities are almost never constant). And if you are using the data to

[R] mixed effects or fixed effects?

Hi, I am running a learning experiment in which both training subjects and controls complete a pretest and posttest. All analyses are being conducted in R. We are looking to compare two training methodologies, and so have run this experiment twice, once with each methodology. Methodology is a

Re: [R] Logistic regression model + precision/recall

Hi. Thnx a lot. I will try that. nitin On 1/24/07, Tobias Sing [EMAIL PROTECTED] wrote: Maybe ROCR might help you. You can visualize the prec/rec-trade-off across the range of all cutoffs: assuming your numerical predictions are in scores and the true class labels are in classes: pred -

[R] Replace missing values in lapply

I have some matrices stored as elements in a list that I am working with. On example is provided below as TP[[18]] TP[[18]] level2 level1 1 2 3 4 1 79 0 0 0 2 0 0 0 0 3 0 0 0 0 4 0 0 0 0 Now, using prop.table on this gives prop.table(TP[[18]],1)

Re: [R] Replace missing values in lapply

you need to return x in the function within lapply(), e.g., something like lapply(TP, function(x) { x[is.na(x)] - 0; x }) I hope it works. Best, Dimitris Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven Address:

Re: [R] Replace missing values in lapply

Perfect, thxs -Original Message- From: Dimitris Rizopoulos [mailto:[EMAIL PROTECTED] Sent: Wednesday, January 24, 2007 10:49 AM To: Doran, Harold Cc: r-help@stat.math.ethz.ch Subject: Re: [R] Replace missing values in lapply you need to return x in the function within

Re: [R] solving a structural equation model using sem or other package

David, Thanks for the help. I missed the significance of the section you quoted below from the help. That does indeed solve the problem. Dan Dan Nordlund Bothell, WA USA -Original Message- From: David Barron [mailto:[EMAIL PROTECTED] Sent: Wednesday, January 24, 2007 3:32 AM

Re: [R] Replace missing values in lapply

I wonder if a list of matrices is the best representation? Do your matrices all have the same dimension as in: TP - list(matrix(c(1:3, NA), 2), matrix(c(NA, 1:3), 2)) # Then you could consider representing them as an array: TPa - array(unlist(TP), c(2,2,2)) # in which case its just

Re: [R] Replace missing values in lapply

I hadn't thought of that. I use the following at one point in my program tmp - with(data, tapply(variable, index, table)) Which returns a list. So, I just went with it for the rest of my program. I'm changing code now to arrays, I think you're right and this may be a better representation. I

[R] as.numeric(.1)

Hello, I noticed the following strange behavior under R-2.4.0 (Linux Mandriva 2007) : options(OutDec) $OutDec [1] . as.numeric(.1) [1] NA Warning message: NAs introduits lors de la conversion automatique as.numeric(,1) [1] 0,1 So I need to use the comma as the decimal separator, at

[R] Fit model to data and use model for data generation

Hi, Suppose I have a set of values x and I want to calculate the distribution of the data. Ususally I would use the density command. Now, can I use the resulting density-object model to generate a number of new values which have the same distribution? Or do I have to use some different function?

Re: [R] as.numeric(.1)

NOEL == NOEL Yvonnick [EMAIL PROTECTED] on Wed, 24 Jan 2007 17:29:14 +0100 writes: NOEL Hello, NOEL I noticed the following strange behavior under R-2.4.0 (Linux Mandriva NOEL 2007) : options(OutDec) NOEL $OutDec NOEL [1] . as.numeric(.1) NOEL [1] NA

[R] Easy to install GNU Emacs for Windows

[Sorry for cross-posting in an attempt to reach as many interested parties as possible.] Users (present or future) of GNU Emacs and ESS on Windows might be interested in my distribution of an easy to install (read: with an installation wizard) version of GNU Emacs 21.3 with the following

Re: [R] as.numeric(.1) + SessionInfo

as.numeric(,1) NOEL [1] 0,1 Instead of the output below, can you please give the full sessionInfo() output? Here it is: R version 2.4.0 (2006-10-03) i686-pc-linux-gnu locale: fr_FR.UTF-8 attached base packages: [1] methods stats graphics grDevices utils

Re: [R] how to write randomforest in r

myat wai wmyonwesit at gmail.com writes: Dear Sir, I want to know how to do for getting the results. 1. data set is not in r. how to use my data set in r. 2. using randomForest function to build tree with my data set how to write for it 3. using this random forest how to predict the new

[R] Cronbach's alpha

Dear Listers: I used cronbach{psy} to evaluate the internal consistency and some set of variables gave me alpha=-1.1003, while other, alpha=-0.2; alpha=0.89; and so on. I am interested in knowing how to interpret 1. negative value 2. negative value less than -1. I also want to re-mention my

Re: [R] Cronbach's alpha

Weiwei Something is wrong. Coefficient alpha is bounded between 0 and 1, so negative values are outside the parameter space for a reliability statistic. Recall that reliability is the ratio of true score variance to total score variance. That is var(t)/ var(t) + var(e) If all variance is true

[R] n step ahead forecasts

hello, I have a question about making n step ahead forecasts in cases where test and validation sets are availiable. For instance, I would like to make one step ahead forecasts on the WWWusage data so I hold out the last 10 observations as the validation set and fit an ARIMA model on the first

[R] dataframe operation

hi i have a dataframe a which looks like: column1, column2, column3 10,12, 0 NA, 0,1 12,NA,50 i want to replace all values in column1 to column3 which do not contain NA with values of vector b (100,200,300). any idea i can do it? i appreciate any hint regards lukas °°° Lukas

Re: [R] dataframe operation

On Wed, 2007-01-24 at 20:27 +0100, Indermaur Lukas wrote: hi i have a dataframe a which looks like: column1, column2, column3 10,12, 0 NA, 0,1 12,NA,50 i want to replace all values in column1 to column3 which do not contain NA with values of vector b (100,200,300). any idea i

Re: [R] dataframe operation

On Wed, 2007-01-24 at 14:10 -0600, Marc Schwartz wrote: On Wed, 2007-01-24 at 20:27 +0100, Indermaur Lukas wrote: hi i have a dataframe a which looks like: column1, column2, column3 10,12, 0 NA, 0,1 12,NA,50 i want to replace all values in column1 to column3 which do not

Re: [R] dataframe operation

Hint: Try ?subset at the R prompt Indermaur Lukas [EMAIL PROTECTED] wrote: hi i have a dataframe a which looks like: column1, column2, column3 10,12, 0 NA, 0,1 12,NA,50 i want to replace all values in column1 to column3 which do not contain NA with values of vector b

[R] RODBC

Hello, I am fairly new to R and its connectivity to MS-Access. I just installed RODBC and it seems to be working well except when I use the date to condition the query. For example the query below sqlQuery(channel, select date from tblUScpi where (date d2) order by date) returns the

[R] Query about extracting subset of datafram

Hi I have a table read from a mysql database which is of the kind clusterid clockrate I obtained this table in R as clockrates_table -sqlQuery(channel,select); I have a function within which I wish to extract the clusterid for a given cluster. Although I know that there is just one row per

Re: [R] dataframe operation

On Wed, 2007-01-24 at 14:16 -0600, Marc Schwartz wrote: On Wed, 2007-01-24 at 14:10 -0600, Marc Schwartz wrote: On Wed, 2007-01-24 at 20:27 +0100, Indermaur Lukas wrote: hi i have a dataframe a which looks like: column1, column2, column3 10,12, 0 NA, 0,1 12,NA,50

[R] Importing XPORT datasets into R

Hi, I'm experiencing a strange issue while attempting to import some XPORT formatted datasets created using SAS 9.3. I 'm using R 2.2.1 with a recently downloaded version of the foreign package, although I don't have the version for that handy. I have been able to load some of the XPORT

Re: [R] Cronbach's alpha

Harold Weiwei-- Actually, alpha *can* go negative, which means that items are reliably different as opposed to reliably similar. This happens when the sum of the covariances among items is negative. See the ATS site below for a more thorough explanation:

[R] User defined function calls

Hi I have a script processfiles.R that contains, amongst other functions 1) a database access function called get_clockrates which retreives from a database, a table containing columns (clusterid, clockrate) and 45000 rows(one for each clusterid). Clusterid is an integer and clockrate is a float.

Re: [R] Query about extracting subset of datafram

On Wed, 2007-01-24 at 12:31 -0800, lalitha viswanath wrote: Hi I have a table read from a mysql database which is of the kind clusterid clockrate I obtained this table in R as clockrates_table -sqlQuery(channel,select); I have a function within which I wish to extract the

[R] Probabilities calibration error ROCR

Hello, I'd need to compute the calibration error of posterior class probabilities p(y|x) estimated by using rpart as classification tree. Namely, I train rpart on a dataset D and then use predict(... type=prob) to estimate p(y|x). I've found the possibility to do that in the ROCR package, but

Re: [R] Cronbach's alpha

Hi Dave We had a bit of an off list discussion on this. You're correct, it can be negative IF the covariance among individual items is negative AND if that covariance term is larger than the sum of the individual item variances. Both of these conditions would be needed to make alpha go negative.

Re: [R] dataframe operation

Here is a slight variation on Marc's idea: isna - is.na(DF) DF[] - replace(100 * col(isna), isna, NA) On 1/24/07, Marc Schwartz [EMAIL PROTECTED] wrote: On Wed, 2007-01-24 at 14:16 -0600, Marc Schwartz wrote: On Wed, 2007-01-24 at 14:10 -0600, Marc Schwartz wrote: On Wed, 2007-01-24 at

[R] JOB: LARS Package Developer

Insightful is seeking a Research Scientist with a strong background in statistical methodology, algorithms development, data analysis, and software development. The primary responsibilities are to develop software for high-dimensional regression and machine learning applications using least

[R] JOB: LARS internships

Insightful is seeking a pre-doctoral student and an undergraduate student for two internship positions. The primary responsibilities are to assist in the development of software for high-dimensional regression and machine learning applications using least angle regression (LARS). The

[R] Text position in Traditional Graphics

R 2.4.1 on Windows XP. Question: In traditional graphics, is it possible to find out the height of a line of text in units that can be used in arithmetic and then in calls to text()? Context: I have written a function that draws a plot and then, depending on whether some arguments are TRUE or

Re: [R] Cronbach's alpha

Hi, there: I read that article (thanks Chucks, etc to point that out). Now I understand how those negatives are generated since my research subject should have negative convariance but they are measuring the same thing. So, I am confused about this same thing and about if it is proper to go ahead

[R] modify rectangle color from image

Hi, I need some suggestion on how I could modify the color on some rectangle that I have created using image. In other words, I have a 5x5 matrix, say, m. m - matrix(rnorm(25), nrow=5) I create a grid of rectangles by: image(m) Now I want to change the color of rectangle

Re: [R] n step ahead forecasts

Dear Spencer: just my2cent: could you change the step from 1 to m, like 5 if you have a very large validation set. I have a feeling that it won't change too much about the result but I am not sure what your endpoint is. weiwei On 1/24/07, sj [EMAIL PROTECTED] wrote: hello, I have a question

Re: [R] Text position in Traditional Graphics

A few days a go Jim Holman [EMAIL PROTECTED] suggested this (Re: [R] How to annotate a graph with non-transparent math labels?) for a similar circumstance. Perhaps it will for in your case. try using strwidth strheight x-c(0,1) plot(x,x,type='l')

Re: [R] Text position in Traditional Graphics

On Wed, 2007-01-24 at 16:30 -0500, Mike Prager wrote: R 2.4.1 on Windows XP. Question: In traditional graphics, is it possible to find out the height of a line of text in units that can be used in arithmetic and then in calls to text()? Context: I have written a function that draws a

Re: [R] Text position in Traditional Graphics

Mike Prager [EMAIL PROTECTED] wrote: R 2.4.1 on Windows XP. Question: In traditional graphics, is it possible to find out the height of a line of text in units that can be used in arithmetic and then in calls to text()? [...] I seem to have solved my own question by setting the user

Re: [R] modify rectangle color from image

Thanks, Saurav Saurav Pathak [Wed, Jan 24, 2007 at 04:37:20PM -0500]: + Hi, + + I need some suggestion on how I could modify the color on some + rectangle that I have created using image. + + In other words, I have a 5x5 matrix, say, m. + + m - matrix(rnorm(25), nrow=5) +

Re: [R] mixed effects or fixed effects?

Hi Dan, this is an interesting and intricate question, but only marginally related to the subject line. On Wed, Jan 24, 2007 at 03:25:39PM +, dan kumpik wrote: Hi, I am running a learning experiment in which both training subjects and controls complete a pretest and posttest. All

Re: [R] Text position in Traditional Graphics

If you are going to take this approach, you may want to look at the cnvrt.coords function in the TeachingDemos package. That may save you a few calculations. -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare [EMAIL PROTECTED] (801) 408-8111 -Original

Re: [R] modify rectangle color from image

On Wed, 2007-01-24 at 16:37 -0500, Saurav Pathak wrote: Hi, I need some suggestion on how I could modify the color on some rectangle that I have created using image. In other words, I have a 5x5 matrix, say, m. m - matrix(rnorm(25), nrow=5) I create a grid of rectangles by:

Re: [R] Cronbach's alpha

Continuing off topic: 1. The range of alpha -infinity alpha 1. 2. Alpha is NOT reliability 3. There are trivial examples of alpha 1 with reliability approaching 1. 4. There are trivial examples of alpha = 0 with reliability approaching 1. 5. Alpha cannot assess dimensionality. Lucke, Joseph

Re: [R] RODBC

On 1/24/2007 3:25 PM, jgaseff wrote: Hello, I am fairly new to R and its connectivity to MS-Access. I just installed RODBC and it seems to be working well except when I use the date to condition the query. For example the query below sqlQuery(channel, select date from tblUScpi where

Re: [R] Cronbach's alpha

Even if the grouping of variables has been fixed by domain knowledge, it does not mean there is unidimensionality in your items (at least for the sample of folks you have). For example, math reasoning and math fluency could both be conceptually put into a single math test, but, assuming a random

Re: [R] Probabilities calibration error ROCR

Roberto, On 1/24/07, Roberto Perdisci [EMAIL PROTECTED] wrote: [...]. Do you know of any reference where I can find the details of the algorithm that computes the calibration error implemented in ROCR (apart from ROCR's source code)? we use it as defined in Caruana Niculescu-Mizil: Data

[R] using non-ASCII strings in R packages

Hello dear useRs and wizaRds, I am currently developing a package that will enable to use administrative map of Poland in R plots. Among other things I wanted to include region names in proper Polish language so that they can be used in creating graphics etc. I am working on Windows and when I

[R] poly(x) workaround when x has missing values

Often in practical situations a predictor has missing values, so that poly crashes. For instance: x-1:10 y- x - 3 * x^2 + rnorm(10)/3 x[3]-NA lm( y ~ poly(x,2) ) Error in poly(x, 2) : missing values are not allowed in 'poly' lm( y ~ poly(x,2) , subset=!is.na(x)) # This does not help?!?

[R] Days of the week?

Hi WizaRds, What is the standard way to get the day of the week from a date such as as.Date(2006-12-01)? It looks like fCalendar has some functions but this requires a change in the R locale to GMT. Is there another way? Thanks! Jack. - Be a PS3 game guru.

Re: [R] Days of the week?

?Date seems to say that weekdays() is appropriate for that: weekdays(as.Date(2006-12-01)) see: ?weekdays On 1/25/07, John McHenry [EMAIL PROTECTED] wrote: Hi WizaRds, What is the standard way to get the day of the week from a date such as as.Date(2006-12-01)? It looks like fCalendar has

[R] Size of data vs. needed memory...rule of thumb?

I have been searching all day most of last night, but can't find any benchmarking or recommendations regarding R system requirements for very large (2-5GB) data sets to help guide our hardware configuration. If anybody has experience with this they're willing to share or could anybody point me

Re: [R] Days of the week?

On 24 January 2007 at 17:39, John McHenry wrote: | What is the standard way to get the day of the week from a date such | as as.Date(2006-12-01)? It looks like fCalendar has some functions | but this requires a change in the R locale to GMT. Is there another way? Yes, go to POSIXlt and extract

Re: [R] Days of the week?

You can use as.numeric(format(d, %w)) . See ?strptime and also the help desk article in R News 4/1. On 1/24/07, John McHenry [EMAIL PROTECTED] wrote: Hi WizaRds, What is the standard way to get the day of the week from a date such as as.Date(2006-12-01)? It looks like fCalendar has some

Re: [R] Fit model to data and use model for data generation

On Jan 24, 2007, at 10:34 AM, Benjamin Otto wrote: Hi, Suppose I have a set of values x and I want to calculate the distribution of the data. Ususally I would use the density command. Now, can I use the resulting density-object model to generate a number of new values which have the

[R] as.numeric(.1) under RGtk2

Prof Brian Ripley a écrit : I can reproduce this via Sys.setlocale(LC_NUMERIC, fr_FR) [1] fr_FR Warning message: setting 'LC_NUMERIC' may cause R to function strangely in: setlocale(category, locale) as.numeric(,1) [1] 0,1 as.numeric(.1) [1] NA Warning message: NAs introduced by

[R] [R-pkgs] version 0.3 of QCA

Dear list members, A new version of the QCA package is now on CRAN. The QCA package implements the Quine-McCluskey algorithm for boolean minimizations, according to the Qualitative Comparative Analysis. Along with the additional improvements in version 0.3-1 (soon to be released on CRAN),

Re: [R] as.numeric(.1) under RGtk2

This seems to be a conflict between GTK+ and R. Apparently, GTK+ sets the locale by itself. There is a way to prevent GTK+ from doing that. I will release a hotfix for RGtk2 soon and we'll see if it fixes it. I just need to run gtk_disable_setlocale() before gtk_init_check(). Thanks for reporting

[R] R programming question, one dimensional optimization

Hi, I have an optimization for x'Ax/x'Bx, x is a vector, A/B are matrix, I wrote a small program which can take in 2 matrices and a vector and a  variable, this  program combine the variable and the vector and generate a new vector, then  test the  x'Ax/x'Bx. However I dodnot know if there is a 

Re: [R] poly(x) workaround when x has missing values

Orthpgpnality of polynomials is not defined if they contain missing values, which seems a good enough reason to me. Put it another way, in your solution whether the columns are orthogonal depends on the unknown values of the NAs, and it looks like is only true if the unknown values are all

[R] rpart question

I make classification tree like this code p.t2.90 - rpart(y~aa_three+bas+bcu+aa_ss, data=training,method=class,control=rpart.control(cp=0.0001)) Here I want to set weight for 4 predictors(aa_three,bas,bcu,aa_ss). I know that there is a weight set-up in rpart. Can this set-up satisfy my need?

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