[R] 3 questions regarding matrix copy/shuffle/compares

[David Winsemius]

On Apr 26, 2009, at 9:43 AM, Esmail wrote:

> David Winsemius wrote:
>> Yes. As I said before "I am going to refrain from posting  
>> speculation until you provide valid R code
>> that will create an object that can be the subject of operations."
>
>
> The code I have provided works, here is a run that may prove helpful:
>
> POP_SIZE = 6
> LEN = 8
>
> pop=create_pop_2(POP_SIZE, LEN)
>
> print(pop)
>      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
> [1,]    0    1    0    1    1    0    0    1
> [2,]    0    0    0    0    0    0    0    0
> [3,]    1    1    0    0    1    0    0    0
> [4,]    0    0    0    0    0    0    0    1
> [5,]    0    0    1    1    0    0    1    0
> [6,]    1    0    0    0    0    0    1    0
> [7,]    0    0    0    0    0    0    0    0
> [8,]    0    0    0    0    0    0    0    0
> [9,]    0    0    0    0    0    0    0    0
> [10,]    0    0    0    0    0    0    0    0
> [11,]    0    0    0    0    0    0    0    0
> [12,]    0    0    0    0    0    0    0    0
>
> I want to (1) create a deep copy of pop,

I have already said *I* do not know how to create a "deep copy" in R.

> (2) be able to shuffle the rows only, and

I have suggested that shuffling by way of a random selection of an   
external index:

 > pop=create_pop_2(POP_SIZE, LEN)
[1] 48
 > pop
       [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
  [1,]    1    1    0    0    1    0    1    1
  [2,]    1    0    1    0    0    0    1    0
  [3,]    1    1    0    1    0    1    0    0
  [4,]    0    0    0    0    1    0    0    0
  [5,]    1    0    0    1    1    1    1    1
  [6,]    1    1    0    0    0    0    0    0
  [7,]    0    0    0    0    0    0    0    0
  [8,]    0    0    0    0    0    0    0    0
  [9,]    0    0    0    0    0    0    0    0
[10,]    0    0    0    0    0    0    0    0
[11,]    0    0    0    0    0    0    0    0
[12,]    0    0    0    0    0    0    0    0

 > dx <- sample(1:nrow(pop), nrow(pop) )
 > dx
  [1] 12 10  8  9  3  1  6 11  5  7  4  2
 > pop[dx,]
       [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
  [1,]    0    0    0    0    0    0    0    0
  [2,]    0    0    0    0    0    0    0    0
  [3,]    0    0    0    0    0    0    0    0
  [4,]    0    0    0    0    0    0    0    0
  [5,]    1    1    0    1    0    1    0    0
  [6,]    1    1    0    0    1    0    1    1
  [7,]    1    1    0    0    0    0    0    0
  [8,]    0    0    0    0    0    0    0    0
  [9,]    1    0    0    1    1    1    1    1
[10,]    0    0    0    0    0    0    0    0
[11,]    0    0    0    0    1    0    0    0
[12,]    1    0    1    0    0    0    1    0

> (3) be able to compare two copies of these objects
> for equality and have it return True if only the rows have been  
> shuffled.

I see two possible questions, the first easier (for me) than the  
second. Do you want to work on a copy with a known permutation of  
rows... or on a copy with an unknown ordering? In the first case I am  
unclear why you would not create an original and a copy, work on the  
copy, and compare with the original that is also sorted by the  
external index.
>
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
Heritage Laboratories
West Hartford, CT