Displaying 20 results from an estimated 1400 matches similar to: "distribution functions and lists"
2013 Mar 10
1
Error with grad() for numerical differential of a function
Hello everyone,
I have programmed a function and, among other things, it has to compute the differential of a function. I have been using the function grad() and I have programmed some simulated studies. I have testes with 72,576 different combinations of the initial values and now I got an error in only 4 situations.
The error comes from the function grad() and I don't understand why. This
2010 May 26
2
Survival analysis extrapolation
Dear all,
I'm trying to fit a curve to some 1 year failure-time data, so that I can
extrapolate and predict failure rates up to 3 years. The data is in the
general form:
Treatment Time Status
Treatment A 28 0
Treatment B 28 0
Treatment B 28 0
Treatment A 28
2011 Nov 07
1
Problema with Excel files
Hi,
I have a Excel file with three spreadsheets: PlanA, PlanB
and PlanC.
I'm trying to read the three spreadsheets and then adding
them together.
But, when I try read the PlanA there is an error message:
rm(list=ls())
setwd('C:/Test/Dados/Teste')
require(RODBC)
Arquivo = odbcConnectExcel('T070206_1347.xls')
(Geral = sqlFetch(Arquivo, 'PlanA'))
(Lactacao =
2008 Feb 08
2
Catching NaNs from pweibull()
Hello,
I am working with the nls() function and inserting a formula into it that
uses the pweibull function. However the pweibull function is annoyingly
producing NaNs, which nls() refuses to handle. I have put a sample of the
code below. Is there a way to prevent these NaNs from interfering, for
example a method to catch them? I get the following error when I try to run
the code:
res.nls <-
2002 May 11
4
Is this a bug of pweibull()?
In rw1050, I found that
> pweibull(3:10, 2)
[1] 0.9998766 0.9999999 1.0000000 1.0000000 NaN NaN
[7] NaN NaN
Warning message:
NaNs produced in: pweibull(q, shape, scale, lower.tail, log.p)
more surprisingly,
> pweibull(3:10, 2.1)
[1] 0.9999566 1.0000000 1.0000000 -Inf NaN NaN
[7] NaN NaN
Warning message:
NaNs produced in: pweibull(q,
2011 Jun 23
2
Confidence interval from resampling
Dear R gurus,
I have the following code, but I still not know how to estimate and extract
confidence intervals (95%CI) from resampling.
Thanks!
~Adriana
#data
penta<-c(770,729,640,486,450,410,400,340,306,283,278,260,253,242,240,229,201,198,190,186,180,170,168,151,150,148,147,125,117,110,107,104,85,83,80,74,70,66,54,46,45,43,40,38,10)
x<-log(penta+1)
plot(ecdf(x),
2002 May 12
2
Is this a bug of pweibull()? (Follow up)
Please allow me to add just a little more about this:
nothing wrong with pweibull(), namely, the two cases I reported:
pweibull(3:10, 2) and pweibull(3:10, 2.1),
in rw1041 and earlier version.
I wonder this might just due to the change from rw1041 to rw1050,
however, I can't find anything relevant (seems to me) in the News
or Readme.
Thanks Sundar for the suggestion of using 1 -
2008 Nov 26
1
survreg and pweibull
Dear all -
I have followed the thread the reply to which was lead by Thomas
Lumley about using pweibull to generate fitted survival curves for
survreg models.
http://tolstoy.newcastle.edu.au/R/help/04/11/7766.html
Using the lung data set,
data(lung)
lung.wbs <- survreg( Surv(time, status)~ 1, data=lung, dist='weibull')
curve(pweibull(x, scale=exp(coef(lung.wbs)),
2008 Mar 02
1
Problem plotting curve on survival curve (something silly?)
OK this is bound to be something silly as I'm completely new to R -
having started using it yesterday. However I am already warming to its
lack of 'proper' GUI... I like being able to rerun a command by editing
one parameter easily... try and do that in a Excel Chart Wizzard!
I eventually want to use it to analyse some chemotherapy response /
survival data. That data will not be
2005 Jan 09
3
"so old bootloader ..." with syslinux-3.05 on x86_64
Hi,
I'm trying to install Fedora Core 3 on an AMD 64-based machine using PXE (via DHCP and TFTP). I've managed to get the machine to load the kernel over the network and start booting, but instead of loading the root fs from initrd.img (that I appended as a config via pxelinux.cfg), it loads the pre-existing rootfs on my harddisk.
At the top of dmesg is the message: "so old
2004 Apr 22
1
slower execution in R 1.9.0
I have an R function (about 1000 lines long) that takes more than 20
times as long to run under R Windows 1.9.0 and 1.8.1 than it does under
1.7.1. Profile results indicate that the $<-.data.frame operation is
the culprit, but I don't understand exactly what that is (assignment of
data frame elements to another variable?), or why it's only a problem
under 1.8.1 and 1.9.0. Any advice?
2005 Jan 09
4
More on Problems with PXELinux and ramdisk not loading
Had to changed the Subject header because the mailing list software thought the previous one ("so old bootloader" ...) was suspicious.
Just a backgrounder and a little more info I've gathered:
Trying to install Fedora Core 3 via PXE using DHCP-TFTP. Kernel loads but initrd isn't used for rootfs.
The machine's an AMD Athlon 64-based box with 512MB physical memory (one DDR
2010 Sep 21
2
Survival curve mean adjusted for covariate: NEED TO DO IN NEXT 2 HOURS, PLEASE HELP
Hi
I am trying to determine the mean of a Weibull function that has been fit to
a data set, adjusted for a categorical covariate , gender (0=male,1=female).
Here is my code:
library(survival)
survdata<-read.csv("data.csv")
##Fit Weibull model to data
WeiModel<-survreg(Surv(survdata$Time,survdata$Status)~survdata$gender)
summary(WeiModel)
P<-pweibull(n,
2010 Mar 01
1
Fitting chi-squared distribution
Dear all,
I have a question regarding performing test if the data fits chi-squared
distribution.
For example, using ks.test()
I found in the examples how to fit it to gamma or weibull
x<-rnorm(100)
ks.test(x, "pweibull", shape=2,scale=1)
for the gamma, pgamma can be used
But I cannot find the value of this second parameter for the chi-squared
distribution.
Maybe someone
2012 Jan 04
1
KS and AD test for Generalized PAreto and Generalized Extreme value
Dear R helpers,
I need to use KS and AD test for Generalized Pareto and Generalized extreme value.
E.g. if I need to use KS for Weibull, I have teh syntax
ks.test(x.wei,"pweibull", shape=2,scale=1)
Similarly, for AD I use
ad.test(x, distr.fun, ...)
My problem is fir given data, I have estimated the parameters of GPD and GEV using lmom. But I am not able to find out the distribution
2011 Oct 20
1
R code Error : Hybrid Censored Weibull Distribution
Dear Sir/madam,
I'm getting a problem with a R-code which calculate Fisher Information
Matrix for Hybrid Censored Weibull Distribution. My problem is that:
when I take weibull(scale=1,shape=2) { i.e shape>1} I got my desired
result but when I take weibull(scale=1,shape=0.5) { i.e shape<1} it gives
error : Error in integrate(int2, lower = 0, upper = t) : the integral is
probably
2004 Nov 05
1
R usage -- for article
Hello all,
I write a decision-support column for a computing magazine,
Intelligent Enterprise. In my next column, I'll be revisiting a topic I
wrote on 3 years ago, open-source analytical software. R is perhaps the
most successful open-source analytical package.
I'd like to hear from users, especially those who chose R for some
other reason than that it's free, about what
2001 Jul 02
1
nls newbie: help approximating Weibull distribution
Hi folks,
I tried to retain the Weibull distribution using the `nls' function
and proceeding along the lines of the example provided in the
`SSweibull' help (at least I thought so):
t <- (1:200)/100
v <- pweibull(t, shape=3, scale=1)
df <- data.frame(Time=t, Value=v)
Asym <- 1.0; Drop <- 1.0; lrc <- 0; pwr <- 1
df.estimate <- nls(Value ~ SSweibull(Time,
2002 Feb 28
1
pweibull.c (PR#1334)
Full_Name: M Welinder
Version: 1.4
OS: (src)
Submission from: (NULL) (192.5.35.38)
It seems to me that pweibull can be improved in the lower_tail=TRUE and
log_p=FALSE
case by using expm1. Something like
-expm1(-pow(x / scale, shape)),
I think.
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read
2008 Aug 21
1
pnmath compilation failure; dylib issue?
(1) ...need to speed up a monte-carlo sampling...any suggestions about
how I can get R to use all 8 cores of a mac pro would be most useful
and very appreciated...
(2) spent the last few hours trying to get pnmath to compile under os-
x 10.5.4...
using gcc version 4.2.1 (Apple Inc. build 5553) as downloaded from
CRAN, xcode 3.0...
...xcode 3.1 installed over top of above after