search for: micknudsen

Displaying 20 results from an estimated 27 matches for "micknudsen".

2009 Jul 14
5
Nested for loops
...=10, the last for loop is over 11:10. Usually programming laguages would regard what corresponds to 11:10 as empty, but A:B with A bigger than B is in R interpreted as the numbers from B to A in reverse order. Is there a clever way to make nested loops like the one above in R? -- Michael Knudsen micknudsen at gmail.com http://lifeofknudsen.blogspot.com/
2009 Sep 30
5
Rounding error in seq(...)
...ative > a = (1:9)/10 works just fine. Are there any good guides out there on how to deal with issues like this? I am normally aware of rounding errors, but it really surprised me to see that an elementary function like seq would behave in this way. Thanks, Michael Knudsen -- Michael Knudsen micknudsen at gmail.com http://sites.google.com/site/micknudsen/
2009 Jul 22
5
Find multiple elements in a vector
...at if I want to find the location of more than one number? I could do c(which(x==2),which(x==3)) but isn't there something more streamlined? My first guess was y=c(2,3) which(x==y) integer(0) which doesn't work. I haven't found any clue in the R manual. Thanks! -- Michael Knudsen micknudsen at gmail.com http://lifeofknudsen.blogspot.com/
2009 Jul 20
5
heatmap plot
Dear R community! I am trying to create a heatmap based on the following data. As you can see the diagonal (0,0 to 10,10) is always 0). If I run the heatmap command like i posted it I get a graph with horizontal lines. What is my mistake? > heatmap(activity.matrix, Rowv = NA, Colv = NA, scale="column", xlab="x Compounds", ylab="y Compounds",
2009 Jul 13
2
graph: axis label font
Hi, excuse me for my english, i am using R on windows and i have to do several graphs with axis labels and the axis text thicks has a specified font type, (Arial) and a specified font size. How can i do these? Thank you in advance -- View this message in context: http://www.nabble.com/graph%3A-axis-label-font-tp24463974p24463974.html Sent from the R help mailing list archive at Nabble.com.
2009 Jul 17
2
Re placing null values (#NULL!)
I am stumped. I have a data set with multiple columns and about 65,000 case. Some of the cases have a "#NULL!" value so for dataframe "Props_": access_emp pct_vacant TAVAIL park PARKACRES totlandare 4538 52.15 #NULL! 0 1 22.99 74,129.70400 4539 52.15 .09 0 1 22.99 982,850.80400 10292 54.20
2009 Jul 18
1
Building a big.matrix using foreach
...foreach I see no other way than to come up with a substitute for c in the .combine option. I have checked out the big.matrix manual, but I can't find a function suitable for just that. Actually, I wouldn't even know how to do it for a usual matrix. Any clues? Thanks! -- Michael Knudsen micknudsen at gmail.com http://lifeofknudsen.blogspot.com/
2009 Aug 13
2
randomForest question--problem with ntree
Hi, I would like to use a random Forest model to get an idea about which variables from a dataset may have some prognostic significance in a smallish study. The default for the number of trees seems to be 500. I tried changing the default to ntree=2000 or ntree=200 and the results appear identical. Have changed mtry from mtry=5 to mtry=6 successfully. Have seen same problem on both a Windows
2009 Aug 17
6
graph label greek symbol failure
Readers, Previous questions about this requirement have been for m$ users, my failure occurs using linux. I have tried to add the delta (?) symbol to the y axis label and the result is &D, using the command: ...ylab="?t"... Any advice please? rhelp at conference.jabber.org mandriva 2008 r 251 (27-06-07)
2009 Jul 13
4
Combine two matricies
Hi, I have two matricies a and x: a<-matrix(c(3,4,5,2,3,4,1,1,2), nrow=3, ncol=3) [,1] [,2] [,3] [1,] 3 2 1 [2,] 4 3 1 [3,] 5 4 2 x<-matrix(c(3, NA, NA, NA, 2, 5, NA, 2, 2), nrow=3, ncol=3) [,1] [,2] [,3] [1,] 3 NA NA [2,] NA 2 2 [3,] NA 5 2 I wish to combine these two into one matrix using the values from x where x has values, and
2009 Jul 16
5
Transformation of data!
Hi Colleagues, Could you please help? I get as the output of my calculations following [1] 0.000000e+00 1.890000e-04 3.933000e-05 1.701501e-04 2.040456e-04 [6] 3.119242e-04 2.545665e-04 1.893930e-03 1.303112e-03 9.880183e-04 [11] 1.504378e-03 1.549246e-03 5.877690e-04 4.771359e-04 8.528219e-04 How is it possible to transform the data to get a vector as following 10
2009 Aug 16
5
Plot(x,y)
Hi , I am using the plot function for some data , and the plot is coming back pure black , with scales on the side . Regards Malcolm [[alternative HTML version deleted]]
2009 Jul 16
4
loading a file in R in mac OS X
Hello, Please forgive me that this question is so basic, but i have not been able to find a solution in any of the basic R introductions, in the R wiki, or in the stats textbook i'm using to learn R. I run R on a macintosh, and i have not been able to load any data files yet. For instance, if I have a data table in a file called schools.txt on my desktop, i've been trying to load the
2009 Jul 20
2
mahalanobis distance
http://www.nabble.com/file/p24569511/mahalanobis.txt mahalanobis.txt http://www.nabble.com/file/p24569511/concentrations.txt concentrations.txt Dear Forum members, I have a problem calculating mahalanobis distances. My data file mahalanobis.txt and categories file concentrations.txt are attached. I do the following steps: x <- as.matrix(read.table("mahalanobis.txt", header=TRUE))
2009 Jul 24
1
downsampling
Hi, I am looking for ways to donwsample one-dimensional vectors. For example, x=sample(1:5, 115, replace=TRUE) How do I downsample this vector to 100 entries? Are there any R functions or packages that provide such functionality. I did find the zoo package and the aggregate() function, but these appear to be rather specific for time-series. Thanks in advance, Jan
2009 Aug 13
2
Matrix addition function
Hello,   What function can I use for matrices addition? I couldn’t find any information about it in the manual or in the internet. (A+B suits, when the number of matrixes is small, function sum() doesn’t suit for matrices addition, because it sums all variables in the matrices and produces as an answer single number, not a matrix).   Best regards, Lina [[alternative HTML version
2009 Sep 11
3
how to determine if a variable is already set?
Hi, It might be a primitive question but how it is possible to determine if a variable is initialized in an environment? Suppose that we start a R session and wants to run a script which use the variable i. Which function could evaluate if i is already initialized or not and if not, then ask interactively the user to set it? This is to avoid the error message: object i is not found. Regards,
2009 Sep 19
2
Use of R in Schools
I am looking for information on experimentation with the use of R in the teaching of statistics and science in schools. Any leads would be very welcome. I am certain that there is such experimentation. I've made this inquiry on r-sig-teaching, with no response. John. John Maindonald email: john.maindonald at anu.edu.au phone : +61 2 (6125)3473 fax : +61 2(6125)5549 Centre
2009 Jul 21
3
writte file doubt
Hi I wrotte this function but when I get the "tmp.xls" file it shows data in a rare way. I mean not appears a matrix with 2000 rows and 100 columns. Can anyone help me, guide me? kim<-function(){ tmp<-randz<-matrix(rnorm(200000, mean=0,sd=0.01 ),2000,100); dim(tmp) write(tmp,file="tmp.xls") Thanks in advance. On the other hand, everytime I execute a function
2009 Jul 20
2
kmeans.big.matrix
...bigmemory) Loading required package: bigmemory > kmeans.big.matrix Error: object 'kmeans.big.matrix' not found Does anybody know how to get the kmeans.big.matrix() function? Are there other cluster algorithms out there ready to accept a big.matrix as input? Thanks! -- Michael Knudsen micknudsen at gmail.com http://lifeofknudsen.blogspot.com/