The cifti format doesn't support that, because it is designed to allow use without loading the entire file into memory - there is no obvious file organization that would allow efficient loading of a full row from a single triangular file, when seek times are nontrivial (rotating disks). I don't believe we have these files in any other format. I'm also not sure how easy it would be to work on such a matrix in matlab. If wb_command is capable of doing the operations you want, it is usually possible for it to do them without loading the entire cifti file into memory at once. wb_view will also display maps from it without loading the entire file into memory.
DDR4 has 16GB modules available at reasonable prices, which should allow recent computers with even 4 slots for memory to expand to 64GB. You should also consider the "high-end desktop" platforms (threadripper, lga2066, lga2011), which typically offer 8 memory slots, and processors with more cores. Tim On Wed, Oct 24, 2018 at 3:56 PM, Reza Rajimehr <rajim...@gmail.com> wrote: > Hi, > > We are trying to unzip and load dense functional connectome > (HCP_S900_820_rfMRI_MSMAll_groupPCA_d4500ROW_zcorr.zip or > HCP_S900_820_rfMRI_MSMSulc_groupPCA_d4500ROW_zcorr.zip from > https://www.humanconnectome.org/study/hcp-young-adult/ > article/announcing-release-of-s900-ptn-and-other-group-average-data) in > Matlab on a system that has 32 GB RAM. This is of course impossible due to > the fact that the files are ~33 GB in size. Due to matrix symmetry, it > would be sufficient to store only the upper or lower triangular part of a > functional connectivity matrix, reducing memory occupancy by about 50% > (Loewe et al., 2016). Does HCP provide such files that could be > memory-friendly? > > Best, > Reza > > _______________________________________________ > HCP-Users mailing list > HCP-Users@humanconnectome.org > http://lists.humanconnectome.org/mailman/listinfo/hcp-users > _______________________________________________ HCP-Users mailing list HCP-Users@humanconnectome.org http://lists.humanconnectome.org/mailman/listinfo/hcp-users
