search for: representaitons

...HA1 Hi, I'm doing some basic operations on large sparse matrices, for example getting a row. it takes close to 30 seconds on a 3Ghz machine, and shots the memory usage up to the sky. I suspect there are dense intermediary steps (which, if true would defeat the purpose of trying to use sparse representaitons). As much as I try understanding the hierarchy of Matrix classes, it's a mystery to me. Is subsetting sparse matrices memory-intensive? Does it have to do with features of the language, such as pass-by-value bu default? Or am I doing something inneficent without knowing? (Note: example below...

For anyone using the development version of R: svn revision 73243 introduces some changes to the memory layout of R objects that require reinstalling packages using compiled code. Attempting to load incompatible packages should signal an error. These changes are to support a new extension framework for basic R objects (https://svn.r-project.org/R/branches/ALTREP/ALTREP.html outlines the