OMEGA matrix should be positive definite, and the one that you use is
not of this class:
> b <- 7
> a <- 9
> b1 <- 7
> aa <- matrix(c(a,b1,0,0,b1,a,b,0,0,b,a,b1,0,0,b1,a),4,4)
> aa
[,1] [,2] [,3] [,4]
[1,] 9 7 0 0
[2,] 7 9 7 0
[3,] 0 7 9 7
[4,] 0 0 7 9
> det(aa)
[1] -2945
Leonid
--------------------------------------
Leonid Gibiansky, Ph.D.
President, QuantPharm LLC
web: www.quantpharm.com
e-mail: LGibiansky at quantpharm.com
tel: (301) 767 5566
Sam Liao wrote:
Dear NONMEM users:
Can someone please help me to solve this problem with a band matrix?
$OMEGA BLOCK(4)
0.09 ;BSV_V1C
0.07 0.09 ;BSV_CLC
0 0.07 0.09 ;BSV_CLN
0 0 0.07 0.09 ;BSV_V1N
Why this one above is getting an error in NONMEM?
$OMEGA BLOCK(4)
0.09 ;BSV_V1C
0.07 0.09 ;BSV_CLC
0 0 0.09 ;BSV_CLN
0 0 0.07 0.09 ;BSV_V1N
This one above is fine, but I need to run a simulation in which there
are some correlation between CLC and CLN.
There were some very helpful discussion on band matrix few years ago.
But I still couldn't figure out why this band matrix not permissible.
Sam Liao
<http://www.cognigencorp.com/nonmem/nm/96mar232001.html>
