R Under development (unstable) (2023-04-23 r84305 ucrt) -- "Unsuffered Consequences"
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> 
>  library(rcdd)
If you want correct answers, use rational arithmetic.
See the Warnings sections in help pages for
    functions that do computational geometry.
> 
>  ##### H-representation #####
> 
>  hrep <- rbind(
+  c(0,  0,  1,  1,  0),
+  c(0,  0, -1,  0,  0),
+  c(0,  0,  0, -1,  0),
+  c(0,  0,  0,  0, -1),
+  c(0,  0, -1, -1, -1))
> 
>  redundant(d2q(hrep), representation = "H")
$output
     [,1] [,2] [,3] [,4] [,5]
[1,] "1"  "0"  "1"  "1"  "0" 
[2,] "1"  "0"  "-1" "0"  "0" 
[3,] "0"  "0"  "-1" "-1" "-1"
attr(,"representation")
[1] "H"

$implied.linearity
[1] 1 2 3

$redundant
[1] 4

$new.position
[1] 1 2 0 0 3

> 
>  redundant(hrep, representation = "H")
$output
     [,1] [,2] [,3] [,4] [,5]
[1,]    1    0    1    1    0
[2,]    1    0   -1    0    0
[3,]    0    0   -1   -1   -1
attr(,"representation")
[1] "H"

$implied.linearity
[1] 1 2 3

$redundant
[1] 4

$new.position
[1] 1 2 0 0 3

> 
>  ##### V-representation #####
> 
>  foo <- c(1, 0, -1)
>  hrep <- cbind(0, 1, rep(foo, each = 9), rep(foo, each = 3), foo)
>  print(hrep)
                foo
 [1,] 0 1  1  1   1
 [2,] 0 1  1  1   0
 [3,] 0 1  1  1  -1
 [4,] 0 1  1  0   1
 [5,] 0 1  1  0   0
 [6,] 0 1  1  0  -1
 [7,] 0 1  1 -1   1
 [8,] 0 1  1 -1   0
 [9,] 0 1  1 -1  -1
[10,] 0 1  0  1   1
[11,] 0 1  0  1   0
[12,] 0 1  0  1  -1
[13,] 0 1  0  0   1
[14,] 0 1  0  0   0
[15,] 0 1  0  0  -1
[16,] 0 1  0 -1   1
[17,] 0 1  0 -1   0
[18,] 0 1  0 -1  -1
[19,] 0 1 -1  1   1
[20,] 0 1 -1  1   0
[21,] 0 1 -1  1  -1
[22,] 0 1 -1  0   1
[23,] 0 1 -1  0   0
[24,] 0 1 -1  0  -1
[25,] 0 1 -1 -1   1
[26,] 0 1 -1 -1   0
[27,] 0 1 -1 -1  -1
> 
>  redundant(d2q(hrep), representation = "V")
$output
     [,1] [,2] [,3] [,4] [,5]
[1,] "0"  "1"  "1"  "1"  "1" 
[2,] "0"  "1"  "1"  "1"  "-1"
[3,] "0"  "1"  "1"  "-1" "1" 
[4,] "0"  "1"  "1"  "-1" "-1"
[5,] "0"  "1"  "-1" "1"  "1" 
[6,] "0"  "1"  "-1" "1"  "-1"
[7,] "0"  "1"  "-1" "-1" "1" 
[8,] "0"  "1"  "-1" "-1" "-1"
attr(,"representation")
[1] "V"

$redundant
 [1]  2  4  5  6  8 10 11 12 13 14 15 16 17 18 20 22 23 24 26

$new.position
 [1] 1 0 2 0 0 0 3 0 4 0 0 0 0 0 0 0 0 0 5 0 6 0 0 0 7 0 8

> 
>  redundant(hrep, representation = "V")
$output
     [,1] [,2] [,3] [,4] [,5]
[1,]    0    1    1    1    1
[2,]    0    1    1    1   -1
[3,]    0    1    1   -1    1
[4,]    0    1    1   -1   -1
[5,]    0    1   -1    1    1
[6,]    0    1   -1    1   -1
[7,]    0    1   -1   -1    1
[8,]    0    1   -1   -1   -1
attr(,"representation")
[1] "V"

$redundant
 [1]  2  4  5  6  8 10 11 12 13 14 15 16 17 18 20 22 23 24 26

$new.position
 [1] 1 0 2 0 0 0 3 0 4 0 0 0 0 0 0 0 0 0 5 0 6 0 0 0 7 0 8

> 
>  ##### another V-representation #####
> 
>  hrep <- rbind(
+  c(0,  0,  1,  0,  0),
+  c(0,  0,  0,  1,  0),
+  c(0,  0,  0,  0,  1),
+  c(0,  0, -1, -1, -1))
> 
>  redundant(d2q(hrep), representation = "V")
$output
     [,1] [,2] [,3] [,4] [,5]
[1,] "1"  "0"  "1"  "0"  "0" 
[2,] "1"  "0"  "0"  "1"  "0" 
[3,] "1"  "0"  "0"  "0"  "1" 
attr(,"representation")
[1] "V"

$implied.linearity
[1] 1 2 3 4

$new.position
[1] 1 2 3 0

> 
>  redundant(hrep, representation = "V")
$output
     [,1] [,2] [,3] [,4] [,5]
[1,]    1    0    1    0    0
[2,]    1    0    0    1    0
[3,]    1    0    0    0    1
attr(,"representation")
[1] "V"

$implied.linearity
[1] 1 2 3 4

$new.position
[1] 1 2 3 0

> 
>  ##### negative new position #####
> 
>  hrep <- rbind(
+  c(1, 0, 1, 0, 0),
+  c(1, 0, 0, 1, 0),
+  c(1, 0, 0, 0, 1),
+  c(1, 0, 0, 1, 0),
+  c(1, 0, 0, 0, 1),
+  c(1, 0, 0, 0, 1))
> 
>  redundant(hrep, representation = "V")
$output
     [,1] [,2] [,3] [,4] [,5]
[1,]    1    0    1    0    0
[2,]    1    0    0    1    0
[3,]    1    0    0    0    1
attr(,"representation")
[1] "V"

$new.position
[1] 1 2 3 0 0 0

> 
> 
> proc.time()
   user  system elapsed 
   0.25    0.01    0.25