Displaying 20 results from an estimated 40000 matches similar to: "How to get the values of a vector having the indices?"
2006 Nov 20
3
Creating a new vector ( another problem)
Dear R Users,
Suppose we are interested for generating a new vector ( x ) from a current vector (y) of length 1000 so that x includes the sum of every 5 values in y respectively from the first to the end of length y. The same length of y for x is desired, so that other 4 positions (indices) in x are filled out with NA.
For generating such a new vector, I have no idea. I tried in some
2006 Nov 20
3
Creating a new vector
Dear R Users,
Suppose we want to creat a new vector ( x ) from a current vector (y) of length 1000. The current vector y includes negative, zero and positive values. We want our new vector x includes the negative values in y, otherwise NA with the same length as y.
For this, we have x=y[y<0] . Now x includes a subset of y with shorter length than y. With x=match(y,x) we would
2005 May 30
2
How to access to sum of dissimilarities in CLARA
Dear All ,
Since dissimilarity is one of quality measures in clustering , I'm trying to access to the sum of dissimilarity as a whole measure. But after running my data using CLARA I obtain :
1128 dissimilarities, summarized :
Min. 1st Qu. Median Mean 3rd Qu. Max.
0.033155 0.934630 2.257000 2.941600 4.876600 8.943700
But I can not find the sum of dissimilarity.How can i
2006 Mar 10
2
creating new vector
Hi R Users,
I don't know how much is difficult my problem and even it is possible to solve in R or not.
Given a vector with 2000 observations. I want to creat a new vector from that vector so that new vector be the sum of every 5 observations sequently. That is , each new observation is sum of every 5 sequent observations, from the first observation of previous vector to the end. So
2005 May 13
1
clustering
Hi Every body,
In order to deal with nonstationary problem in time series, may be firstly clustering algorithms are used to partition time series .Then another algorithm is used to predict future value based on segmented data in the second phase. Using clustering algorithms , the "time structure and arrangement" of time series is confused. We have some partitions including data
2006 Jan 08
2
Filters in waveslim
Dear R Users,
For running wavelet functions using dwt( ), modwt( ), and mra( ), a wavelet filter algorithm is applied. For all these functions, default is "la8" and other possibility is "haar". In related documents, another possibilities like as symlet and coiflet ... are not cited.
Besides "la8" and "haar", which wavelet filters can be used?
Thank
2005 Jun 01
2
How to name variables in a single plot
Dear R Friends ,
I want to name my variables( more than 2 variables in a single plot) within a plot to distinct them from each other, but I cann't. How it is possible? I don't mean x and y axis using xlab or ylab. At the below , it follows some lines, only as an example that you could try please, if it is possible. I really thanks for your attention.
Amir
library(graphics)
y<-
2005 May 31
1
How to access to Data within a cluster
Dear All ,
For more process on data resulting clustering, one needs to access data within any cluster. How it is possible in CLARA?
$clustering :gives us clustering vector as mixed, so it isn't as separate
$clusinfo : gives us dissimilarities,
Thanks a lot
Amir
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2005 Nov 29
2
Calculating the 2th power of a vector
Hi every body ,
I simply want to calculate the 2th power of a vector without changing the sign of values. How it is possible in R ?
Thanks a lot for any idea.
Amir
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2007 Aug 14
1
Slack variable in OR
Hi dear R users,
Is it basically correct that a problem is ( linearly on nonlinearly ) modeled so that the slack variable is bounded by an upper bound ?
If so, how it can be handled and coded practically ?
for example:
x1+ x2 =< b so ----> x1 + x2 + s=b
s=b- x1 - x2
b- x1 - x2 =< upper value
But algorithms can not calculate b- x1 - x2 , because
2005 Aug 24
1
Packages
Hi Dear All,
I want to instal some packages, but I can not find them in both lists of Package Index in internet ( http://www.maths.lth.se/help/R/.R/doc/html/packages.html ) and of Instalation of Packages window in the softwar. For example "modreg". Are they included in larger packages ?
Thanks for your help.
Best Regards,
Amir Safari
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2006 Oct 30
1
reading only some columns from a table
Dear R users,
Sometimes it is needed to read only some columns from a table, in particulare for high frequency data. How it is possible to read just some certain columns using read.table ( ). The reason could be keeping space in R and in particular accelerating in reading data when the number of rows are huge and some of them are not needed.
Thank you very much,
Amir
2006 Feb 07
2
Prediction method for lowess,loess,lokerns,lpepa,ksmooth
Hi Every Body,
I don't know why some regression functions have no related prediction function. For example lowess, loess, lokerns, lpridge, lpepa, and ksmooth.
What could help? Is there any global or wrapper function so that can help?
Regards,
Amir Safari
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2006 Jan 17
1
Vector indices
Hi,
I am despairing of getting the indices for a vector:
First, I have a table from which I kick out a number of rows with na.omit. Next, I use this table for clustering with kmeans and cl$cluster contains my clusters. The cl$cluster is a vector which still contains my original indices from the very beginning, a kind of like an "associative" array. But how can I get a list of
2005 Aug 11
1
How to insert a certain model in SVM regarding to fixed kernels
Dear David,
Dear R Users ,
Suppose that we want to regress for example a certain autoregressive model using
SVM. We have our data and also some fixed kernels in libSVM behinde e1071
in front. The question: Where can we insert our certain autoregressive
model ? During creating data frame ? Or perhaps we can make a
relationship between our variables ended to desired autoregressive model ?
2005 Jun 29
2
comparison of packages for Unit Root test
Dear R Users,
Could somebody please compare the packages of unit root test ( Uroot, Ucra, tseries and fseries ) regarding the type of test ( without constant and trend, with constant , and with constant and trend ) ?
Regards,
Amir Safari
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2005 Jun 29
2
Running SVM {e1071}
Dear David, Dear Friends,
After any running svm I receive different results of Error estimation of 'svm' using 10-fold cross validation. What is the reason ? It is caused by the algorithm, libsvm , e1071 or something els? Which value can be optimal one ? How much run can reach to the optimality.And finally, what is difference between Error estimation of svm using 10-fold cross validation
2005 Dec 07
2
Bandwidth selection for ksmooth( )
Dear R Users,
Before running ksmooth( ), a suitable bandwidth selection is needed. I use some functions for this task and receive these results for my data:
width.SJ(y,nb=100,method="ste") : 40.25
bcv(y,nb=100) : 40.53
ucv(y) : 41.26
bandwidth.nrd(y) : 45.43
After implementing the function ksmooth(x,y, bandwidth= each of abovementioned bandwidths), I have some NAs
2006 Apr 05
1
Combination of Bias and MSE ?
Dear R Users,
My question is overall and not necessarily related to R.
Suppose we face to a situation in which MSE( Mean Squared Error) shows desired results but Bias shows undesired ones, Or in advers. How can we evaluate the results. And suppose, Both MSE and Bias are important for us.
The ecact question is that, whether there is any combined measure of two above metrics.
Thank you so
2006 Jun 26
1
How to generate a figure using par( ) with some densityplot( )'s
Hi Dear R users,
For a pair plotting, usaully we use par( ) function. Apparently it does not work anywhere. I want to have 3 plots in a single figure, like this:
par(mfrow=c(3,1))
densityplot( a)
densityplot(b)
densityplot(c)
But it does not work. How is it possible to have such a figure with densityplot( ) in a single figure?
So many thanks for any help.
Amir Safari