home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Turnbull China Bikeride
/
Turnbull China Bikeride - Disc 1.iso
/
ARGONET
/
PD
/
MATHS
/
RLAB
/
RLAB125.ZIP
/
!RLaB
/
help_sz
/
svd
< prev
next >
Wrap
Text File
|
1994-02-21
|
1KB
|
48 lines
svd:
Syntax: svd ( A )
svd ( A , TYPE )
Description:
Computes the singular values of the input matrix A, as well as
the right and left singular vectors in various forms. Where:
A = U * diag (sigma) * Vt
The output is a list containing the three afore-mentioned
objects (u, sigma, vt). Various forms of the right and left
singular vectors can be computed, depending upon the value of
the second argument, TYPE.
TYPE: `"S"' A minimal version of U, and V' are returned.
This is the default.
TYPE: `"A"' The full U, and V' are returned.
TYPE: `"N"' U and V' are not computed, empty U and V' are
returned.
The LAPACK subroutine DGESVD, or ZGESVD is used to perform the
computation.
Example:
> A = [0.96, 1.72; 2.28, 0.96];
> Asvd = svd(A)
sigma u vt
> Asvd.vt
matrix columns 1 thru 2
-0.8 -0.6
0.6 -0.8
> Asvd.u
matrix columns 1 thru 2
-0.6 -0.8
-0.8 0.6
> Asvd.sigma
vector elements 1 thru 2
3 1
> check = Asvd.u * diag(Asvd.sigma) * Asvd.vt
check =
matrix columns 1 thru 2
0.96 1.72
2.28 0.96