View source: R/distributions_implementations.R
nimSvd | R Documentation |
Computes singular values and, optionally, left and right singular vectors of a numeric matrix.
nimSvd(x, vectors = "full")
x |
a symmetric numeric matrix (double or integer) whose spectral decomposition is to be computed. |
vectors |
character that determines whether to calculate left and right singular vectors. Can take values |
Computes the singular value decomposition of a numeric matrix using the Eigen C++ template library.
The vectors
character argument determines whether to compute no left and right singular vectors ('none'
), thinned left and right singular vectors ('thin'
), or full left and right singular vectors ('full'
). For a
matrix x
with dimensions n
and p
, setting vectors = 'thin'
will does the following (quoted from eigen website):
In case of a rectangular n-by-p matrix, letting m be the smaller value among n and p, there are only m singular vectors;
the remaining columns of U and V do not correspond to actual singular vectors.
Asking for thin U or V means asking for only their m first columns to be formed.
So U is then a n-by-m matrix, and V is then a p-by-m matrix.
Notice that thin U and V are all you need for (least squares) solving.
Setting vectors = 'full'
will compute full matrices for U and V, so that U will be of size n-by-n, and V will be of size p-by-p.
In a nimbleFunction
, svd
is identical to nimSvd
.
returnType(svdNimbleList())
can be used within a link{nimbleFunction}
to specify that the function will return a nimbleList
generated by the nimSvd
function. svdNimbleList()
can also be used to define a nested nimbleList
element. See the User Manual for usage examples.
The singular value decomposition of x
is returned as a nimbleList
with elements:
d length m vector containing the singular values of x
, sorted in decreasing order.
v matrix with columns containing the left singular vectors of x
, or an empty matrix if vectors = 'none'
.
u matrix with columns containing the right singular vectors of x
, or an empty matrix if vectors = 'none'
.
NIMBLE development team
nimEigen
for spectral decompositions.
singularValuesDemoFunction <- nimbleFunction(
setup = function(){
demoMatrix <- diag(4) + 2
},
run = function(){
singularValues <- svd(demoMatrix)$d
returnType(double(1))
return(singularValues)
})
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.