Displaying 20 results from an estimated 20000 matches similar to: "library MASS fitdistri() funciotn question"
2008 Aug 06
1
Problem in using MASS
Dear Sir
I am very new user of R project. Sir I am a research scholar. I am doing work on fitting distributions. Sir in using MASS package I am facing the following errors for my data.
fitdistr(urban$x, "gamma")Error in fitdistr(urban$x, "gamma") : 'x' must be a non-empty numeric vector
Would you please help in this regard.
Kind Regards
Tayyaba
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",
2008 Jun 11
2
MLE Estimation of Gamma Distribution Parameters for data with 'zeros'
Greetings, all
I am having difficulty getting the fitdistr() function to return without
an error on my data. Specifically, what I'm trying to do is get a
parameter estimation for fracture intensity data in a well / borehole.
Lower bound is 0 (no fractures in the selected data interval), and upper
bound is ~ 10 - 50, depending on what scale you are conducting the
analysis on.
I read in the
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
2011 Jan 07
0
Fitting an Inverse Gamma Distribution to Survey Data
Hello,
I've been attempting to fit the data below with an inverse gamma
distribution. The reason for this is outside proprietary software (@Risk)
kicked back a Pearson5 (inverse gamma) as the best fitting distribution with
a Chi-Sqr goodness-of-fit roughly 40% better than with a log-normal fit.
Looking up "Inverse gamma" on this forum led me the following post:
2011 Jan 13
1
Fitting an Inverse Gamma Distribution
http://r.789695.n4.nabble.com/file/n3216865/Inverse_Gamma.png
Hello,
I am seeking help in estimating the parameters of an inverse gamma
distribution (from the 'actuar' package) using a function like 'fitdistr'.
Unfortunately I haven't found such a package using findFn('fit Inverse
Gamma') from the 'sos' package and was therefore hoping someone might be
aware
2010 Jun 16
2
Fitting Gamma distribution
I'm looking for goodness of fit tests for gamma distributions with large data
sizes and for different data.
I have a matrix with around 4.000 data values in it and i have fitted a
gamma distribution with "fitdistr".
You can see the example:
> fitdistr(corpo,"gamma",lower=0.001)
Errore in optim(x = c(5000, 5000, 5000, 5000, 5000, 5000, 5000, 5000,
5000, :
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
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
2012 Feb 15
1
Parameter estimation of gamma distribution
Hi,
I am trying to estiamte parameters for gamma distribution using mle for
below data using fitdist & fitdistr functions which are from "fitdistrplus"
& "MASS"packages . I am getting errors for both functions. Can someone
please let me know how to overcome this issue??
data
y1<-
c(256656, 76376, 6467673, 46446, 3400, 3100, 5760, 4562, 8000, 512, 4545,
4562,
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'
2002 Jan 29
1
fitdistr() in MASS library
Prof Brian Ripley wrote:
>
> Even better, use the function fitdistr in package MASS...
>
I had a look in my MASS library (from the package VR_6.2-6) and couldn't
find this function. Is there a newer version available? Thanks for any
help.
Jim
This email message and any accompanying attachments may contain confidential information. If you are not the intended recipient, do not
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
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
2009 Oct 26
0
MLE for noncentral t distribution
Hi,
Actually I am facing a similar problem. I would like to fit both an ordinary (symmetric) and a non-central t distribution to my (one-dimensional) data (quite some values.. > 1 mio.).
For the symmetric one, fitdistr or funInfoFun (using fitdistr) from the qAnalyst package should do the job, and for the non-central one.. am I right to use
gamlss(x ~ 1, family=GT()) ?
Anyway, I am a little
2008 Feb 10
1
Error in optim while using fitdistr() function for estimation of parameters
Hello,
I am trying to fit distribution for data consisting of 421 readings.It is
basically no of requests arrived per minute.It contains many 0 entries as no
of requests.When i use
fd<-fitdistr(V2,"gamma")
I get following error:
Error in optim(x = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, :
initial value in 'vmmin' is not finite
What should I do ? I need
2005 Aug 27
1
bug in L-BFGS-B? (PR#8099)
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Content-Transfer-Encoding: 7bit
G'day all,
I believe that this is related to PR#1717 (filed under
not-reproducible) which was reported for a version of R that is a
quite a bit older than the ones used in for this report. But I
noticed this behaviour under R 2.1.1 and R 2.2.0 on my linux box and
2010 Jan 12
1
Strange behavior when trying to piggyback off of "fitdistr"
Hello.
I am not certain even how to search the archives for this particular question, so if there is an obvious answer, please smack me with a large halibut and send me to the URLs.
I have been experimenting with fitting curves by using both maximum likelihood and maximum spacing estimation techniques. Originally, I have been writing distribution-specific functions in 'R' which work
2008 Dec 24
1
Non-finite finite difference error
Hello, I'm trying to use fitdistr() from the MASS package to fit a gamma
distribution to a set of data. The data set is too large (1167 values) to
reproduce in an email, but the summary statistics are:
Min. 1st Qu. Median Mean 3rd Qu. Max.
116.7 266.7 666.7 1348.0 1642.0 16720.0
The call I'm trying to make is:
fitdistr(x,"gamma")
and the error is:
Error in optim(x =
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