symm.prod | R Documentation |
Given the order of a symmetrizer matrix \bold{N}
of order n
and a
conformable matrix \bold{X}
, performs one of the matrix-matrix operations:
\bold{Y} = \bold{NX}
, if side = "left"
, or
\bold{Y} = \bold{XN}
, if side = "right"
,
The main aim of symm.prod
is to do this matrix multiplication without forming
the symmetrizer matrix.
symm.prod(n = 1, x = NULL, side = "left")
n |
order of the symmetrizer matrix. |
x |
numeric matrix (or vector). |
side |
a string selecting if symmetrizer matrix is pre-multiplying |
Underlying C
code only uses information provided by symm.info
to
performs the matrix multiplication. The symmetrizer matrix is never created.
symmetrizer
N4 <- symmetrizer(n = 4, matrix = TRUE)
x <- matrix(1:32, ncol = 2)
y <- N4 %*% x
z <- symm.prod(n = 4, x) # N4 is not stored
all(z == y) # matrices y and z are equal!
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.