On Jul 12, 2010, at 7:16 AM, S.Nicholas wrote:
Thank you Erik and Patrick,
using vectorization and apply function seem to be very promising, even
though I don't know how to use apply/sapply for updating discrete time
difference equation instead of using for loop.
(e.g, Nt+1 = Nt (1+R(K-Nt/K)))
Maybe I could use vector for different parameters,
and for loop for updating the equation.
Loops methods:
b0 <- rnorm(10)
b1 <- c(0,b0[2:(length(b0)-1)] ) # shifted one time interval
?lag
?diff
See also section 4 (page 9) of this exposition for worked examples of
using R for discrete-time difference equations:
http://www.soa.org/files/pdf/UsingRforActuarialScience.pdf
--
David
Best,
Nic
On Sun, Jul 11, 2010 at 1:02 PM, Patrick Connolly <
p_conno...@slingshot.co.nz> wrote:
On Fri, 09-Jul-2010 at 08:25AM -0700, S.Nicholas wrote:
|> deaR useRs,
|>
|> I am trying to assign different values to different objects in a
for
loop.
|> The following is a toy example of the part that has been giving
me a
hard
|> time.
|>
|> The first "for loop" generates four objects, b0, b1, b2, b3 with
random
|> numbers.
|> And, the second "for loop" is equivalent to
|> b1 = b0
|> b2 = b1
|> b3 = b2
|> b4 = b3
I don't quite get the idea, but would you be able to simply reverse
the order of those last 4 (for i in 3:0)? That way, they won't all
be
overwritten with b0.
HTH
|>
|> But, when I run this code, the result is equivalent to
|> b1 = b0
|> b2 = b0
|> b3 = b0
|> b4 = b0
|>
|> So, the increment does not seem to be properly working for the
second
part
|> of the "assign" function.
|> Why would this be?
|>
|> for (i in 0:3)
|> {
|> r = runif(1)
|> assign(paste('b',i,sep=''),r)
|> }
|>
|>
|> for (i in 1:4)
|> {
|>
|>
assign(paste('b',i,sep=''),eval(parse(text=paste('b',i-1,sep=''))))
|> }
|>
|> Thank you.
|>
|> Nic
|>
|> [[alternative HTML version deleted]]
|>
|> ______________________________________________
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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.
--
~
.~
.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.
___ Patrick Connolly
{~._.~} Great minds discuss ideas
_( Y )_ Average minds discuss events
(:_~*~_:) Small minds discuss people
(_)-(_) ..... Eleanor Roosevelt
~
.~
.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
