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This page (revision-10) was last changed on 27-Sep-2013 17:17 by Andrew Tikhonov

This page was created on 02-Jun-2011 09:10 by Rodrigo Santamaria

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At line 20 added 24 lines
# __Choose a dataset to preprocess or upload your own data__ \\ aPE can be used on the EBI R-Cloud to pre-process private datasets by uploading its corresponding CEL files to your R/Bioconductor Workbench account. \\ You can also pre-process public datasets available through ArrayExpress. \\ You can use this [interface|http://www.ebi.ac.uk/arrayexpress/] to search for a dataset.\\ \\
# __Launch the R-Cloud Workbench, register and create a new project__ \\ The EBI R-Cloud is a new service at the EBI which allows R users to log in and run distributed computational jobs remotely on its powerful 64-bit linux cluster. This is available through a Java client called the ArrayExpress R/Bioconductor Workbench. Open the following address in a browser and follow the instructions on the page to download or launch the Workbench: [http://www.ebi.ac.uk/tools/rcloud] \\ \\ When connecting for the first time you will be requested to register. You will need to set/provide a username, password and e-mail address to allow you to retrieve your long running projects the next time you log in. Once registered you can log in and create a new project.\\ \\ [Find your way around the workbench|http://www.ebi.ac.uk/Tools/rcloud/quick_start.html] \\ \\
# __Pre-process your data__ \\ If your CEL files are in a folder 'td', running affyParaEBI within R is straightforward with the following simple code: \\ {{{
> library(affyParaEBI)
> cluster <- makeCluster(10,type="RCLOUD")
> e <- preproParaEBI(path=td, clust=cluster)
> stopCluster(cluster); rm(cluster)
}}} \\ \\ When the pipeline finishes, 'e' will contain an ExpressionSet object that can then be used for downstream analysis. \\ \\ The pre-processing will take time depending on the size of the dataset and how many computing nodes were allocated with "makeCluster" (10 in the above example). Typically, 50 nodes can pre-process 1000 CEL files in about 20 minutes. \\ \\ If you want to pre-process one or more experiments available in ArrayExpress, you can download the CEL files to a folder via ArrayExpress R/Bioconductor package: \\{{{
> library(ArrayExpress)
> library(affyParaEBI)
> #1) Create a two-node cluster
> cluster<-makeCluster(2,type="RCLOUD")
> #2) Retrieve CEL files from experiment E-MEXP-328
> td<-tempdir()
> emexp328.raw<-ArrayExpress(input = "E-MEXP- 328", path=td, save=TRUE)
> #3) Replace low performance nodes
> cluster<-clusterOptimization(cluster, subst=TRUE)
> #4) Perform parallel preprocessing of CEL files
> emexp328.proc<-preproParaEBI(path=td, clust=cluster)
> #5) Clean up cluster nodes and CEL files
> stopCluster(cluster); rm(cluster)
> file.remove(list.files(td, full.names=TRUE))
}}} \\
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[affyParaEBI_1.0.tar.gz|http://www.ebi.ac.uk/Tools/rcloud/downloads/affyParaEBI.tar.gz]
[affyParaEBI_1.0.0.tar.gz|http://www.ebi.ac.uk/Tools/rcloud/downloads/affyParaEBI_1.0.0.tar.gz]
Version Date Modified Size Author Changes ... Change note
10 27-Sep-2013 17:17 3.713 kB Andrew Tikhonov to previous
9 10-Jan-2012 11:43 3.643 kB Andrew Tikhonov to previous | to last
8 02-Jun-2011 10:04 3.635 kB Rodrigo Santamaria to previous | to last
7 02-Jun-2011 09:58 3.647 kB Rodrigo Santamaria to previous | to last
6 02-Jun-2011 09:57 3.651 kB Rodrigo Santamaria to previous | to last
5 02-Jun-2011 09:50 3.662 kB Rodrigo Santamaria to previous | to last
4 02-Jun-2011 09:48 3.731 kB Rodrigo Santamaria to previous | to last
3 02-Jun-2011 09:34 0.931 kB Rodrigo Santamaria to previous | to last
2 02-Jun-2011 09:17 2.498 kB Rodrigo Santamaria to previous | to last
1 02-Jun-2011 09:10 1.787 kB Rodrigo Santamaria to last
« This page (revision-10) was last changed on 27-Sep-2013 17:17 by Andrew Tikhonov