Description Usage Arguments Details Value Author(s) See Also Examples

View source: R/patternRepeat.R

Recreate patterns for collapsed arrays

1 | ```
patternRepeat(x, which, n, careful = TRUE, keep.order = FALSE)
``` |

`x` |
A vector to be repeated. |

`which` |
Which indices of the implicit array are given in |

`n` |
Dimensions of implicit array. |

`careful` |
logical indicating whether to check vailidty of arguments, but therefore slow things down. |

`keep.order` |
logical indicating whether to respect the ordering of the
entries in the vector |

These functions allow for the construction of complex repeating patterns
corresponding to those obtained by unwrapping arrays. Consider an array
with dimensions `n`

; then for each value of the dimensions in
`which`

, this function returns a vector which places the corresponding
entry of `x`

into every place which would match this pattern when the
full array is unwrapped.

For example, if a full 4-way array has dimensions 2*2*2*2 and we consider the margin of variables 2 and 4, then the function returns the pattern c(1,1,2,2,1,1,2,2,3,3,4,4,3,3,4,4). The entries 1,2,3,4 correspond to the patterns (0,0), (1,0), (0,1) and (1,1) for the 2nd and 4th indices.

In `patternRepeat()`

the argument `x`

is repeated according to the
pattern, while `patternRepeat0()`

just returns the indexing pattern.
So `patternRepeat(x,which,n)`

is effectively equivalent to
`x[patternRepeat0(which,n)]`

.

The length of `x`

must be equal to `prod(n[which])`

.

Both return a vector of length `prod(n)`

;
`patternRepeat()`

one containing suitably repeated and ordered elements
of `x`

, for `patternRepeat0()`

it is always the integers from 1 up
to `prod(n[which])`

.

Robin Evans

1 2 3 4 5 6 7 8 9 10 | ```
patternRepeat(1:4, c(1,2), c(2,2,2))
c(array(1:4, c(2,2,2)))
patternRepeat0(c(1,3), c(2,2,2))
patternRepeat0(c(2,3), c(2,2,2))
patternRepeat0(c(3,1), c(2,2,2))
patternRepeat0(c(3,1), c(2,2,2), keep.order=TRUE)
patternRepeat(letters[1:4], c(1,3), c(2,2,2))
``` |

rje42/rje documentation built on Dec. 10, 2018, 7:01 a.m.

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