Sorry for possible misunderstanding:
I want to define a matrix (B) based on an existing matrix (A) in a single
step and keep A unchanged:
> #Existing matrix
> A=matrix(1:16,ncol=4)
> A
[,1] [,2] [,3] [,4]
[1,] 1 5 9 13
[2,] 2 6 10 14
[3,] 3 7 11 15
[4,] 4 8 12 16
> # New matrix B is defined to be the submatrix after row1 and column1 are
> deleted.
> B=A[-1,-1] # this single step deletes row1 nad column 1 and assigns the
> name to the resulting submatrix.
> B # check the new matrix B
[,1] [,2] [,3]
[1,] 6 10 14
[2,] 7 11 15
[3,] 8 12 16
> A # check the original matrix A
[,1] [,2] [,3] [,4]
[1,] 1 5 9 13
[2,] 2 6 10 14
[3,] 3 7 11 15
[4,] 4 8 12 16
Question: How can I do define a new matrix (D) by adding 2*row1 to row3 in A
in a single step as what was done in the above example?
If you do: A[3,]=2*A[1,]+A[3,], the new A is not the original A; if you
D=A first, then D[3,]=2*D[1,]+D[3,], you used two step!
Hope this clarifies my original question. Thanks again.
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