[R] Reshaping an array - how does it work in R
jdnewmil at dcn.davis.ca.us
Fri Mar 18 23:11:38 CET 2016
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.mendelssohn at noaa.gov> wrote:
>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
>myData[noLat*noLon, noTime]. Normally this would be easy:
>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.
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