On Jul 2, 2012, at 10:09 PM, Tjun Kiat Teo wrote:
I am trying to to write a wrapper function for the ode solver (under
the package desolve) to enable it to take multivariate arrays. I know
how to do it for 1 dimension arrays but my code breaks down when I try
to do it for 2 dimensional arrays. Here is my code
diffwrap<-function(t,y,mu)vdpol(t=t,A[1:3,1:4]<-y[1:12],B[1:12]<-
y[13:24],mu=mu)
I do not know whether this explains your problems , but it generally
is very dangerous practice to have items in function argument lists
like: A[1:3,1:4]<-y[1:12] and B[1:12]<-y[13:24]
I've often received similar messages when I mistaken entered "<-"
rather than "=" in that situation.
The code runs with this definition (after loading pkg:deSolve rather
than 'desolve'):
diffwrap<-function(t,y,mu) vdpol(t=t, A = matrix(y[1:12], 3,4),
B=y[13:24], mu=mu)
Whether the output is sensible mathematically is beyond my knowledge,
--
David
vdpol<-function(t,A,B,mu)
{
list(c(mu,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
A[1,1],
A[2,1],
A[3,1],
A[1,2],
A[2,2],
A[3,2],
A[1,3],
A[2,3],
A[3,3],
A[1,4],
A[2,4],
A[3,4])
)
}
stiff<-ode(y=rep(0,24),times=c(0,1),func=diffwrap,parms=1)
I get keep getting the error message variable A[1,1] not found.
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David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
