[R] A matrix automation problem

[Ben Bolker]

megh <megh700004 <at> yahoo.com> writes:

> 
> 
> [I am really sorry if it is double posted, I doubt me previous post could not
> reach forum due to some problem with net]
> 
> Suppose I have a matrix :
> 
> a = matrix(1:9, 3)
> 
> >From this matrix, I construct 9 additional matrices :
> 
> i = 1:9
> bi = a * i
> 
> Now combining all those 9 new matrices, I construct a final metrix as :
> 
> c = 
> 
> b1 b4 b7
> b2 b5 b8
> b3 b6 b8
> 
> I want to automate this procedure for any arbitrary number "i"
>


  It may be too specialized, but it sounds like you're looking
for a Kronecker product.

 a = matrix(1:9,3)
> kronecker(a,a)
      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
 [1,]    1    4    7    4   16   28    7   28   49
 [2,]    2    5    8    8   20   32   14   35   56
 [3,]    3    6    9   12   24   36   21   42   63
 [4,]    2    8   14    5   20   35    8   32   56
 [5,]    4   10   16   10   25   40   16   40   64
 [6,]    6   12   18   15   30   45   24   48   72
 [7,]    3   12   21    6   24   42    9   36   63
 [8,]    6   15   24   12   30   48   18   45   72
 [9,]    9   18   27   18   36   54   27   54   81

  Ben Bolker