ff: vectorIndex2arrayIndex – R documentation

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vectorIndex2arrayIndex

Array: make array from index vector positions

Description

make array from index vector positions respecting dim and dimorder

Usage

vectorIndex2arrayIndex(x, dim = NULL, dimorder = NULL, vw = NULL)

Arguments

`x`	a vector of indices in `seq_len(prod(dim))`
`dim`	NULL or `dim`
`dimorder`	NULL or `dimorder`
`vw`	NULL or integer matrix[2,m], see details

Details

The fastest rotating dimension is dim[dimorder[1]], then dim[dimorder[2]], and so forth.
The parameters 'x' and 'dim' may refer to a subarray of a larger array, in this case, the array indices 'x' are interpreted as 'vw[1,] + x' within the larger array 'vw[1,] + x + vw[2,]'.

Value

an n by m matrix with n m-dimensional array indices

Author(s)

Jens Oehlschlägel

Examples

matrix(1:12, 3, 4)
  vectorIndex2arrayIndex(1:12, dim=3:4)
  vectorIndex2arrayIndex(1:12, dim=3:4, dimorder=2:1)
  matrix(1:30, 5, 6)
  vectorIndex2arrayIndex(c(6L, 7L, 8L, 11L, 12L, 13L, 16L, 17L, 18L, 21L, 22L, 23L)
, vw=rbind(c(0,1), c(3,4), c(2,1)))
  vectorIndex2arrayIndex(c(2L, 8L, 14L, 3L, 9L, 15L, 4L, 10L, 16L, 5L, 11L, 17L)
, vw=rbind(c(0,1), c(3,4), c(2,1)), dimorder=2:1)

ff

Memory-Efficient Storage of Large Data on Disk and Fast Access Functions

v4.0.4

GPL-2 | GPL-3 | file LICENSE

Authors

Daniel Adler [aut], Christian Gläser [aut], Oleg Nenadic [aut], Jens Oehlschlägel [aut, cre], Martijn Schuemie [aut], Walter Zucchini [aut]

Initial release

2020-10-13