Displaying 4 results from an estimated 4 matches for "bestmem".
Did you mean:
testmem
2012 Dec 16
1
nls for sum of exponentials
...kage to pick the
most optimal start values -
fm4 <- function(x) x[1] + x[2]*exp(x[3] * -dist) + x[4]*exp(x[5] * -dist)
fm5 <- function(x) sum((wcorr-fm4(x))^2)
fm6 <- DEoptim(fm5, lower=c(0,0.1,1,0.1,1), upper=c(10e7, 100, 300,100, 300
), control=list(trace=FALSE))
par2 <- fm6$optim$bestmem
names(par2) <- c("c", "A", "n1", "B", "n2")
fit2 <- nls(wcorr ~ (c + A*exp(n1 * -dist) + B*exp(n2 * -dist)),
start=par2,control
=list(maxiter=1000, warnOnly=TRUE))
However, I keep getting the following error -
Error in numericDeriv(form[[3...
2012 Feb 10
3
Schwefel Function Optimization
All,
I am looking for an optimization library that does well on something as chaotic as the Schwefel function:
schwefel <- function(x) sum(-x * sin(sqrt(abs(x))))
With these guys, not much luck:
> optim(c(1,1), schwefel)$value
[1] -7.890603
> optim(c(1,1), schwefel, method="SANN", control=list(maxit=10000))$value
[1] -28.02825
> optim(c(1,1), schwefel, lower=c(-500,-500),
2012 Feb 10
3
Schwefel Function Optimization
All,
I am looking for an optimization library that does well on something as chaotic as the Schwefel function:
schwefel <- function(x) sum(-x * sin(sqrt(abs(x))))
With these guys, not much luck:
> optim(c(1,1), schwefel)$value
[1] -7.890603
> optim(c(1,1), schwefel, method="SANN", control=list(maxit=10000))$value
[1] -28.02825
> optim(c(1,1), schwefel, lower=c(-500,-500),
2009 Dec 01
2
Starting estimates for nls Exponential Fit
Hello everyone,
I have come across a bit of an odd problem: I am currently analysing data
PCR reaction data of which part is behaving exponential. I would like to fit
the exponential part to the following:
y0 + alpha * E^t
In which Y0 is the groundphase, alpha a fluorescence factor, E the
efficiency of the reaction & t is time (in cycles)
I can get this to work for most of my reactions,