```
# NOT RUN {
(pm1 <- as(as.integer(c(2,3,1)), "pMatrix"))
t(pm1) # is the same as
solve(pm1)
pm1 %*% t(pm1) # check that the transpose is the inverse
stopifnot(all(diag(3) == as(pm1 %*% t(pm1), "matrix")),
is.logical(as(pm1, "matrix")))
set.seed(11)
## random permutation matrix :
(p10 <- as(sample(10),"pMatrix"))
## Permute rows / columns of a numeric matrix :
(mm <- round(array(rnorm(3 * 3), c(3, 3)), 2))
mm %*% pm1
pm1 %*% mm
try(as(as.integer(c(3,3,1)), "pMatrix"))# Error: not a permutation
as(pm1, "ngTMatrix")
p10[1:7, 1:4] # gives an "ngTMatrix" (most economic!)
## row-indexing of a <pMatrix> keeps it as an <indMatrix>:
p10[1:3, ]
# }
```

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