Displaying 20 results from an estimated 14000 matches similar to: "fitdistr() in MASS library"
2008 Oct 30
1
Is possible, on biological grounds, suggest to fitdistr (MASS library) that the estimated parameters must be between two values?
Sorry if it is a silly question, I haven't found documentation on this and I
don't know if it is possible.
library(MASS) ## for fitdistr
library(msm) ## for dtnorm
#prepare truncated normal distribution
dtnorm0 <- function(x, mean, sd , log = FALSE) {
dtnorm(x, mean, sd, 105, 135, log)
}
set.seed(1)
#Generate normal distribution with the TRUE population mean (day 106 of the
2004 Oct 27
1
Warning messages in function fitdistr (library:MASS)
Why the warning messages (2:4)?
> x <- rexp(1000,0.2)
> fitdistr(x,"exponential",list(rate=1))
rate
0.219824219
(0.006951308)
Warning messages:
1: one-diml optimization by Nelder-Mead is unreliable: use optimize in: optim(start, mylogfn, x = x, hessian = TRUE, ...)
2: NaNs produced in: dexp(x, 1/rate, log)
3: NaNs produced in: dexp(x, 1/rate, log)
4: NaNs
2003 Nov 27
2
MASS fitdistr()
Dear R experts,
I am trying to use the R MASS library fitdistr() to fit the following
list:
k21stsList<-c(0.76697,0.57642,0.75938,0.82616,0.93706,0.77377,0.58923,0.37157,0.60796,1.00070,0.97529,0.62858,0.63504,0.68697,0.61714,0.75227,1.16390,0.66702,0.83578)
as follows,
library(MASS)
fitdistr(k21stsList, "normal")
But, I get
Error in fitdistr(k21stsList, "normal") :
2011 May 03
3
fitting distributions using fitdistr (MASS)
Please guide me through to resolve the error message that I get
this is what i have done.
>x1<- rnorm(100,2,1)
>x1fitbeta<-fitdistr(x1,"beta")
Error in fitdistr(x1, "beta") : 'start' must be a named list
Yes, I do understand that sometime for the distribution to converge to the
given set of data, it requires initial parameters of the distribution, to
2010 Jan 03
6
Help with function "fitdistr" in "MASS"
Hi, R users:
I want to fit my data into a normal distribution by using the command
"fitdistr" in "MASS".
I changed my data class from "ts" to "numeric" by
>class(mydata)="numeric"
but after using "fitdistr", I got the result below
>fitdistr(mydata,"normal")
mean sd
NA NA
(NA) (NA)
the help doc of
2011 Apr 27
3
MASS fitdistr with plyr or data.table?
I am trying to extract the shape and scale parameters of a wind speed
distribution for different sites. I can do this in a clunky way, but
I was hoping to find a way using data.table or plyr. However, when I
try I am met with the following:
set.seed(144)
weib.dist<-rweibull(10000,shape=3,scale=8)
weib.test<-data.table(cbind(1:10,weib.dist))
2004 Feb 17
2
problem with fitdistr ?
Hi,
I'm trying fitdistr but I'm getting some errors
> fitdistr(rnorm(100),"Normal")
Error in fitdistr(rnorm(100), "Normal") : 'start' must be a named list
> fitdistr(rnorm(100),"Normal",start=list(mean=0,sd=1))
Error in fitdistr(rnorm(100), "Normal", start = list(mean = 0, sd = 1))
:
supplying pars for the Normal is not
2008 Sep 19
0
Re lative Novice ? "Can I get some explanation of the docs for fitdistr(MASS)?"
In the docs I see:
Usage
fitdistr(x, densfun, start, ...)
Arguments
x A numeric vector.
densfun Either a character string or a function returning a density
evaluated at its first argument.
Distributions "beta", "cauchy", "chi-squared", "exponential", "f", "gamma",
"geometric", "log-normal", "lognormal",
2010 Jan 28
4
Problems with fitdistr
Hi,
I want to estimate parameters of weibull distribution. For this, I am using
fitdistr() function in MASS package.But when I give fitdistr(c,"weibull") I
get a Error as follows:-
Error in optim(x = c(4L, 41L, 20L, 6L, 12L, 6L, 7L, 13L, 2L, 8L, 22L,
:
non-finite value supplied by optim
Any help or suggestions are most welcomed
--
View this message in context:
2008 Sep 22
0
Warnings in fitdistr() from MASS.
For a lark, I experimented a bit with the data from Ted Byers' recent
postings. The result of fitdistr() seemed sensible, but I was bothered
by the warnings about NaNs that arose. Warnings always make me nervous.
Explicitly this is what I did:
TXT <- "0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2008 Sep 22
0
Re lative novice: Working with fitdistr(MASS): 3 questions
OK, I am now at the point where I can use fitdistr to obtain a fit of one of
the standard distributions to mydata.
It is quite remarkable how different the parameters are for different
samples through from the same system. Clearly the system itself is not
stationary.
Anyway, question 1: I require a visual perspective of the fit I get. I can
use hist.scott to get a hisogram (and just have to
2008 Feb 09
2
print.fitdistr buglet
Dear developers,
There's a small bug in print.fitdistr that can cause output to be printed
twice, but only if print is called explicitly:
> fit<-fitdistr(rt(1000,3),"t")
There were 11 warnings (use warnings() to see them)
> fit
m s df
-0.02181723 1.00145296 3.13723878
( 0.03865057) ( 0.03999447) ( 0.33298377)
> print(fit)
2003 Jul 28
1
Optimization failed in fitting mixture 3-parameter Weibull distri bution using fitdistr()
Dear All;
I tried to use fitdistr() in the MASS library to fit a mixture
distribution of the 3-parameter Weibull, but the optimization failed.
Looking at the source code, it seems to indicate the error occurs at
if (res$convergence > 0)
stop("optimization failed").
The procedures I tested are as following:
>w3den <- function(x, a,b,c)
2006 Sep 23
1
Fitdistr() versus nls()
Hello R-Users,
I'm new to R so I apologize in advance for any big mistake I might
be doing. I'm trying to fit a set of samples with some probabilistic
curve, and I have an important question to ask; in particular I have
some data, from which I calculate manually the CDF, and then I import
them into R and try to fit: I have the x values (my original samples)
and the y values
2003 Jul 25
5
named list 'start' in fitdistr
Hi R lovers!
I'd like to know how to use the parameter 'start' in the function
fitdistr()
obviously I have to provide the initial value of the parameter to optimize
except in the case of a certain set of given distribution
Indeed according to the help file for fitdistr
" For the following named distributions, reasonable starting values
will be computed if `start'
2005 Jul 12
1
three par. fitting with fitdistr
Hello,
I want to fit a tree parameter distribution to given data. I tried it with
sample data using the "fitdistr" function.
Here my workflow that didn't had any result:
I started with the generalized gamma distr, which is:
r*dgamma(x^r,shape,rate)
The R-function is:
ggamma = function (x,r,shape,rate) r*dgamma(x^r,shape,rate=rate)
For the first step I assumed r = 1 and I
2011 Apr 23
0
MASS fitdistr call in plyr help!
I have a set of wind speeds read at different locations. The data is
a data frame with two columns: site and wind speed. I want to split
the data on site and call a function to find the shape and scale
parameters of a weibull distribution fit.
The end result is a plot with x-axis = shape and y-axis = scale.
Currently my code looks like:
fit_wind_speed<-function(x){
2005 Nov 17
1
Problem with fitdistr for gamma in R 2.2.0
Dear R developers,
I have encountered strange behaviour of fitdistr for gamma in recent R
build i.e. 2.2.0. I have attached the code for data at the end of this mail
so you can reproduce the problem. In short, I am able to run fitdistr under
2.1.0 without problems, while I get the following error under 2.2.0
(Version 2.2.0 Patched (2005-11-15 r36348))
> fitdistr(otm, "gamma")
Error
2005 Apr 05
1
Fitdistr and likelihood
Hi all,
I'm using the function "fitdistr" (library MASS) to fit a distribution to
given data.
What I have to do further, is getting the log-Likelihood-Value from this
estimation.
Is there any simple possibility to realize it?
Regards, Carsten
2007 Sep 09
1
fitdistr()
I am trying to fit the chi-squared distribution to a set of data using the fitdistr function found in the MASS4 library, the data set is called ONES3, I have loaded it using the command
ONES3<-read.table("ONES3.pdf",header=TRUE,na="NA")
I print out the dataset ONES3 to the screen to make sure it has loaded
Then I try to fit this data using the command