Displaying 20 results from an estimated 10000 matches similar to: "D(dnorm...)?"
2009 Aug 07
1
Gauss-Laguerre using statmod
I believe this may be more related to analysis than it is to R, per se.
Suppose I have the following function that I wish to integrate:
ff <- function(x) pnorm((x - m)/sigma) * dnorm(x, observed, sigma)
Then, given the parameters:
mu <- 300
sigma <- 50
m <- 250
target <- 200
sigma_i <- 50
I can use the function integrate as:
> integrate(ff, lower= -Inf, upper=target)
2019 Dec 07
2
What should dnorm(0, 0, -Inf) return?
Hi,
Apropos of a recent Inf question, I've previously wondered if dnorm "does the right thing" with
dnorm(0, 0, -Inf)
which gives zero. Should that be zero or NaN (or NA)?
The help says "'sd < 0' is an error and returns 'NaN'" and since -Inf < 0 is TRUE, then... is this a bug?
Thank you,
Stephen
Rochester, MN USA
2010 Jul 06
1
plotmath vector problem; full program enclosed
Here's another example of my plotmath whipping boy, the Normal distribution.
A colleague asks for a Normal plotted above a series of axes that
represent various other distributions (T, etc).
I want to use vectors of equations in plotmath to do this, but have
run into trouble. Now I've isolated the problem down to a relatively
small piece of working example code (below). If you would
2019 Dec 08
2
What should dnorm(0, 0, -Inf) return?
Yes, that looks like a bug and an easily fixable one too.
However, I spy another issue: Why do we check the !R_FINITE(x) && mu == x before checking for sd < 0 ? The difference is whether we
return ML_NAN;
or
ML_ERR_return_NAN;
but surely negative sd should always be an error?
I'd be inclined to do
if (sigma < 0) ML_ERR_return_NAN;
if(!R_FINITE(sigma)) return R_D__0;
2012 Mar 23
3
R numerical integration
Hi all,
Is there any other packages to do numerical integration other than the
default 'integrate'?
Basically, I am integrating:
integrate(function(x) dnorm(x,mu,sigma)/(1+exp(-x)),-Inf,Inf)$value
The integration is ok provided sigma is >0.
However, when mu=-1.645074 and sigma=17535.26
It stopped working. On the other hand, Maple gives me a value of
0.5005299403.
It is an
2010 Mar 09
3
Shade area under curve
I want to shade the area under the curve of the standard normal density.
Specifically color to the left of -2 and on. How might i go about doing
this?
Thanks
--
View this message in context: http://n4.nabble.com/Shade-area-under-curve-tp1586439p1586439.html
Sent from the R help mailing list archive at Nabble.com.
2008 Jan 31
1
Ryacas
I'm tinkering around in Ryacas trying to find an easy way to get the
first and second partial derivatives of mu and sigma from a normal
distribution (actually a bitterly ugly likelihood but this example works
for now).
I've done all of the work in Mathematica, but I then need to manually
write R code whereas I think Ryacas will give me the expression such
that I can export for Tex and
2008 Oct 01
2
Bivariate normal
Package mvtnorm provides dmvnorm, pmvnorm that can be used to compute
Pr(X=x,Y=y) and Pr(X<x,Y<y) for a bivariate normal.
Are there functions that would compute Pr(X<x,Y=y)?
I'm currently using "integrate" with dmvnorm but it is too slow.
2009 Jun 03
1
Would like to add this to example for plotmath. Can you help?
Greetings:
I would like comments on this example and after fixing it up, I need
help from someone who has access to insert this in R's help page for
plotmath.
I uploaded a drawing
http://pj.freefaculty.org/R/Normal-2009.pdf
that is created by the following code
http://pj.freefaculty.org/R/Normal1_2009_plotmathExample.R
This will be a good addition to the plotmath help page/example.
2007 Apr 05
1
Plotting multiple curves with lattice graphs
Hi List,
I would like to plot multiple curves (parametric
density curves) in one plot.
For example:
# parameters for three normal density curves
parms =
data.frame(ID=c(1,2,3),mu=c(50,55,60),sigma=c(10,12,15))
# I can easily draw three normal density curves using
curve():
curve(dnorm(x,mean=parms$mu[1],sd=parms$sigma[1]),from=0,
to=150, ylab="density", col="red")
2012 Mar 22
2
Quicker way to apply values to a function
Hi all,
myint=function(mu,sigma){
integrate(function(x) dnorm(x,mu,sigma)/(1+exp(-x)),-Inf,Inf)$value
}
mymu=seq(-3,3,length(1000))
mysigma=seq(0,1,length(500))[-1]
k=1
v=c()
for (j in 1:length(mymu)) {
for (i in 1:length(mysigma)) {
v[k]=myint(mymu[j],mysigma[i])
k=k+1
}
}
Basically, I want to investigate for what values of mu and sigma, the
integral is divergent.
Is there another way
2008 Dec 31
3
Plotmath with values?
I hope to use the plotmath facility to print titles that mix
math and values of R variables.
The help for "plotmath" has an example, which after repeated
reading, I find baffling. Likewise, I have read the help file
for "substitute" (wqhich seems to be needed) without ever
understanding what it does, other than being used in some magic
incantations.
I would like to do
2008 Jul 23
1
R2WinBUGS problem
Dear friends - I'm on winXP, R 2.71 - I have with some help dveloped
this multivariate normal model, which gives very plausible results in
WinBUGS even without any
initial values specified. However, when I then try to run the same model
via the bugs function in R2WinBUGS with inits specified as inits=NULL
the program stops in a dead end. So I have tried to make inits for the
bugs function
2010 Sep 09
5
Help on simple problem with optim
Dear all,
I ran into problems with the function "optim" when I tried to do an mle estimation of a simple lognormal regression. Some warning message poped up saying NANs have been produced in the optimization process. But I could not figure out which part of my code has caused this. I wonder if anybody would help. The code is in the following and the data is in the attachment.
da <-
2011 Jan 16
3
rootogram for normal distributions
Using R-2.12.1 and latticeExtra-0.6-14, I would like to understand
why a rootogram displaying samples from the Poisson distribution looks like I
expected it, whereas a rootogram using the normal distribution does not:
library(latticeExtra)
rootogram(~rpois(1000, lambda = 50), dfun = function(x) dpois(x, lambda = 50))
rootogram(~rnorm(1000), dfun = function(x) dnorm(x,mean(x),sd(x)))
I
2005 Mar 18
3
plotmath question
R listers:
I have been foiled by plotmath!
(in R 2.01,Windows 2000)
The task: Plot a normal density and label the ticks as mu - 3 sigma, mu - 2
sigma, ...., mu + 3 sigma, where the mu's and sigmas appear as Greek
symbols, of course.
The following code does this:
x<-seq(-3,to=3,by=.01)
y<-dnorm(x)
plot(x,y,type='h',col='lightblue',axes=FALSE)
2009 Dec 03
2
Help R2WinBUGS
Hello,
I have problem running WinBUGS from R.
The following example works in WinBUGS but it does not work in R through
package R2WinBUGS.
Does anyone know what the problem is?
x <- c(0.2, 1.1, 1, 2.2, 2.5, 2.9, 2.9, 3.6, 3.8, 0.6, 1, 2, 2.4, 2.6, 2.8,
3.2, 3.9, 3.5)
y <- c(0.5, 1.3, 0.1, 0.7, -0.4, 0.5, -0.9, -0.3, -0.3, 0.6, 0.4, 0.9, -0.1,
-0.4, -0.5, -0.2, 0.3, -1.5)
eco <- c(1, 3,
2010 Jun 23
1
A question about R2Winbugs
Dear R users:
I was trying to fit a HMM with mixture of Gaussian into the dataset, and I
tried to implement it by R2Winbugs. But I got the following errer.
*
Error in FUN(X[[1L]], ...) :
.C(..): 'type' must be "real" for this format*
Does anybody know what's the problem? Does R2Winbugs accept some matrix as
inits? I would really appreciate your help. Thank you very much.
2006 Oct 31
2
Put a normal curve on plot
I would like to be able to place a normal distribution surrounding the
predicted values at various places on a plot. Below is some toy code
that creates a scatterplot and plots a regression line through the data.
library(MASS)
mu <- c(0,1)
Sigma <- matrix(c(1,.8,.8,1), ncol=2)
set.seed(123)
x <- mvrnorm(50,mu,Sigma)
plot(x)
abline(lm(x[,2] ~ x[,1]))
Say I want to add a normal
2004 Jul 08
1
(PR#7070)
> version
_
platform i686-pc-linux-gnu
arch i686
os linux-gnu
system i686, linux-gnu
status
major 1
minor 7.1
year 2003
month 06
day 16
language R
Bug:
integrate(f,lower,upper,extra_args)
where
f <- function(x,extra_args)
{
body
}
integrate doesn't pass the extra arguments when calling f.
As a first check of this finding I integrated dnorm from