Displaying 20 results from an estimated 2000 matches similar to: "Problems with fitdistr"
2012 Jul 22
1
Adding gamma and 3-parameter log normal distributions to L-moments ratio diagram lmrd()
How to adapt this piece of code but for: - gamma distribution - 3 parameter
log normal
More specifically, where can I find the specification of the parameter
(lmom) for pelgam() and pelln3()?
Lmom package info just gives: pelgam(lmom), lelln3(lmom), where lmom is a
numeric vector containing the L-moments of the distribution or of a data
sample.
# Draw an L-moment ratio diagram and add a line for
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))
2009 Apr 04
2
threshold distribution
Dear ALL
I have a list of data below
0.80010 0.72299 0.69893 0.99597 0.89200 0.69312 0.73613 1.13559
0.85009 0.85804 0.73324 1.04826 0.84002
1.76330 0.71980 0.89416 0.89450 0.98670 0.83571 0.73833 0.66549
0.93641 0.80418 0.95285 0.76876 0.82588
1.09394 1.00195 1.14976 0.80008 1.11947 1.09484 0.81494 0.68696
0.82364 0.84390 0.71402 0.80293 1.02873
all of them are ninty.
Nowaday, i try to find a
2011 Oct 28
1
weibull fitdistr problem: optimization failed
I'm getting errors when running what seems to be a simple Weibull
distribution function:
This works:
x <-
c(23,19,37,38,40,36,172,48,113,90,54,104,90,54,157,51,77,78,144,34,29,45,16,15,37,218,170,44,121)
rate <- c(.01,.02,.04,.05,.1,.2,.3,.4,.5,.8,.9)
year <- c(100,50,25,20,10,5,3.3,2.5,2,1.2,1.1)
library(MASS)
x <- sort(x)
tryCatch(
f<-fitdistr(x, 'weibull'),
error
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)
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'
2011 Aug 06
2
Gamma distribution parameter estimation
Hey,
I have a set of income data which I'd like to fit to a gamma
distribution. How can I estimate the two parameters of the gamma
distribution for a vector, e.g.
c(2039L, 2088L, 5966L, 2353L, 1966L, 2312L, 3305L, 2013L, 3376L,
3363L, 3567L, 4798L, 2032L, 1699L, 3001L, 2329L, 3944L, 2568L,
1699L, 4545L)
I sense this will be a very easy one-liner, but my searching didn't come
up with
2004 Feb 25
2
PWM Help
I saw a Help e-mail related to MLE. Does R have a probability weighted method (PWM) estimator function? I can't seem to find anything on PWM, unless my eyes are playing trick on me.
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2007 Feb 25
2
RFA
Dear Sir in the following example,is the vector lmom a l-moment ratios
vector? What is meant by size = northCascades[,1]? And what are the values
in c(0.0104,0.0399,0.0405)?
Please help me I am unable to understand these from help manual.
Best Regards
AMINA
data(northCascades)
lmom <- c(1, 0.1103, 0.0279, 0.1366)
kappaParam <- kappalmom(lmom)
heterogeneity(500, 19, size =
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
2003 Sep 30
3
fitdistr, mle's and gamma distribution
Dear R Users,
I am trying to obtain a best-fit analytic distribution for a dataset
with 11535459 entries. The data range in value from 1 to 300000000. I
use: fitdistr(data, "gamma") to obtain mle's for the parameters.
I get the following error:
Error in optim(start, mylogfn, x = x, hessian = TRUE, ...) :
non-finite finite-difference value [1]
And the following warnings:
2005 May 18
1
'fitdistr' and two views of the same data?
Hello,
I have detailed (with pictures and whatnot) my question on my weblog at
http://www.cs-ed.org/blogs/mjadud/archives/2005/05/a_question_abou.html
The short version of the question is this:
When I ask 'fitdistr' to try and fit my distribution as a "weibull"
distribution, it comes up with some rather wacky parameters.
If I take the same distribution, and do something
2009 Jul 21
1
lmom - Estimating Normal Distribution Parameters using lmom package
Dear R helpers,
I have a data of 2102 observations (consisting of 0's also), to which I am trying to fit Normal distribution using "lmom" pacakage. If I use Excel, its easy to estimate the parameters of Normal distribution as simple mean and standard devaition. The results I get if I use teh excel are as
Parameters of Normal distribution :-
Mean = 22986.44 and standard
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
2012 Feb 21
3
HELP ERROR Weibull values must be > 0
GUYS,
I NEED HELP WITH ERROR:
library(MASS)
> dados<-read.table("mediaRGinverno.txt",header=FALSE)
> vento50<-fitdistr(dados[[1]],densfun="weibull")
Erro em fitdistr(dados[[1]], densfun = "weibull") :
Weibull values must be > 0
WHY RETURN THIS ERROR? WHAT CAN I DO?
BEST REGARDS
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2009 Nov 16
1
lmomco package and confidence limits?
Hello,
I am using the lmomco package (lmom.ub and pargev) to compute the GEV
parameters (location, scale, and shape), which are used to estimate
return values. I was wondering how/if I can calculate upper and lower
confidence (CI_u, CI_l) intervals for each return frequency using the
GEV parameters to fill-in the table below?
Xi (location) = 35.396
Alpha (scale) = 1.726
Kappa (shape) =
2008 Feb 09
1
Problem with fitdistr function
Hello,
I am using fitdistr function for parameter estimation.
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
fd<-fitdistr(V2,"weibull")
Error in optim(x = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, :
2009 Mar 16
1
Fw: Fitting GUMBEL Distribution - CDF function and P P Plot
Dera R Helpers,
I am re-posting my query.
Please guide me.
Maithili
--- On Fri, 3/13/09, Maithili Shiva <maithili_shiva at yahoo.com> wrote:
I am trying to fit the Gumbel distribution to a data. I am
using lmom package. I am getting problem in Cumulative
Distribution Function of Gumbel distribution as I am getting
it as a series of 0's and 1's thereby affecting the
P P
2008 Oct 07
3
Fitting weibull, exponential and lognormal distributions to left-truncated data.
Dear All,
I have two questions regarding distribution fitting.
I have several datasets, all left-truncated at x=1, that I am attempting
to fit distributions to (lognormal, weibull and exponential). I had
been using fitdistr in the MASS package as follows:
fitdistr<-(x,"weibull")
However, this does not take into consideration the truncation at x=1. I
read another posting in this
2010 Feb 22
1
lmom: plotting log Pearson Type III
Can anyone show me how to add a log Pearson type III plot using the
evdistq() command to an extreme value plot using the lmom package?
Attached sample code below...
Thanks in advance,
Dave
library(lmom)
# annual maximum daily streamflows Mackenzie River
mackenzieRiver = c(26600, 30300, 34000, 32000, 29200, 28300, 28600,
26400, 28300, 28800, 29000, 22100, 32900, 31800, 21600, 32100, 27000,