R always makes a copy for this kind of operation. There are some operations that don't make copies, but I don't think this one qualifies.
-- Sent from my phone. Please excuse my brevity. On March 18, 2016 2:28:35 PM PDT, Roy Mendelssohn - NOAA Federal <roy.mendelss...@noaa.gov> wrote: >Hi All: > >I am working with a very large array. if noLat is the number of >latitudes, noLon the number of longitudes and noTime the number of >time periods, the array is of the form: > >myData[noLat, no Lon, noTime]. > >It is read in this way because that is how it is stored in a (series) >of netcdf files. For the analysis I need to do, I need instead the >array: > >myData[noLat*noLon, noTime]. Normally this would be easy: > >myData<- array(myData,dim=c(noLat*noLon,noTime)) > >My question is how does this command work in R - does it make a copy of >the existing array, with different indices for the dimensions, or does >it just redo the indices and leave the given array as is? The reason >for this question is my array is 30GB in memory, and I don’t have >enough space to have a copy of the array in memory. If the latter I >will have to figure out a work around to bring in only part of the data >at a time and put it into the proper locations. > >Thanks, > >-Roy > > > >********************** >"The contents of this message do not reflect any position of the U.S. >Government or NOAA." >********************** >Roy Mendelssohn >Supervisory Operations Research Analyst >NOAA/NMFS >Environmental Research Division >Southwest Fisheries Science Center >***Note new address and phone*** >110 Shaffer Road >Santa Cruz, CA 95060 >Phone: (831)-420-3666 >Fax: (831) 420-3980 >e-mail: roy.mendelss...@noaa.gov www: http://www.pfeg.noaa.gov/ > >"Old age and treachery will overcome youth and skill." >"From those who have been given much, much will be expected" >"the arc of the moral universe is long, but it bends toward justice" >-MLK Jr. > >______________________________________________ >R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide >http://www.R-project.org/posting-guide.html >and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.