cifti.read.matrix: Read the data matrix of a CIFTI-2 file.
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cifti.read.matrix

R Documentation

Read the data matrix of a CIFTI-2 file.

Read the data matrix of a CIFTI-2 file.

cifti.read.matrix(cii, rows = NULL, columns = NULL)

`cii`	an `fs.cifti` instance, see `read.cifti.header`.
`rows`	integer vector or `NULL`, the indices of matrix dimension 0 to read. Indices are 1-based, like everywhere else in R, and they refer to the rows of the returned array, i.e. to the first CIFTI matrix dimension. Use `NULL` (the default) to read all of them. Note that this selection is applied after reading the whole matrix: use `read.cifti.rows` if the file is too large for that.
`columns`	integer vector or `NULL`, the indices of matrix dimension 1 to read, i.e. the columns of the returned array. This is the matrix dimension that holds the brainordinates of a dense file (the grayordinates of a `.dscalar`, `.dtseries` or `.dlabel`), and it is also one of the two dimensions that hold them in a connectome file like a `.dconn`. Selecting columns avoids reading the rest of the file, which is the only practical way to read a small part of a huge file like a `.dconn` (9 to 38 GB): for a 2-dimensional matrix, one contiguous block of the file holds all values of one column. Note that `rows` does not have this property, selecting rows still reads all values of the file.