DummyDuplicated {SSBtools} | R Documentation |
Duplicated columns in dummy matrix
Description
The algorithm is based on crossprod(x)
or crossprod(x, u)
where u
is a vector of random numbers
Usage
DummyDuplicated(x, idx = FALSE, rows = FALSE, rnd = FALSE)
Arguments
x |
A matrix |
idx |
Indices returned when TRUE |
rows |
Duplicated rows instead when TRUE |
rnd |
Algorithm based on cross product with random numbers when TRUE (dummy matrix not required) |
Details
The efficiency of the default algorithm depends on the sparsity of crossprod(x)
.
The random values are generated locally within the function without affecting the random value stream in R.
Value
Logical vectors specifying duplicated columns or vector of indices (first match)
Author(s)
Øyvind Langsrud
Examples
x <- cbind(1, rbind(diag(2), diag(2)), diag(4)[, 1:2])
z <- Matrix(x[c(1:4, 2:3), c(1, 2, 1:5, 5, 2)])
DummyDuplicated(z)
which(DummyDuplicated(z, rows = TRUE))
# Four ways to obtain the same result
DummyDuplicated(z, idx = TRUE)
DummyDuplicated(z, idx = TRUE, rnd = TRUE)
DummyDuplicated(t(z), idx = TRUE, rows = TRUE)
DummyDuplicated(t(z), idx = TRUE, rows = TRUE, rnd = TRUE)
# The unique values in four ways
which(!DummyDuplicated(z), )
which(!DummyDuplicated(z, rnd = TRUE))
which(!DummyDuplicated(t(z), rows = TRUE))
which(!DummyDuplicated(t(z), rows = TRUE, rnd = TRUE))
[Package SSBtools version 1.5.2 Index]