Displaying 20 results from an estimated 20000 matches similar to: "About searching criteria"
2010 Nov 26
1
How to save a data set as .txt on fly?
Hi folks,
Win7 64bit
I tried to save DNase, a data set on database, as .txt file for future use with
load.
I can't do it on fly;
> save(DNase, file="C:/Users/satimis/Documents/aaa.txt")
> load(file="C:/Users/satimis/Documents/aaa.txt")
> aaa
Error: object 'aaa' not found
> aaa.txt
Error: object 'aaa.txt' not found
I must perform following
2006 Sep 11
4
syntax of nlme
Hello,
How do I specify the formula and random effects without a startup object
? I thought it would be a mixture of nls and lme.
after trying very hard, I ask for help on using nlme.
Can someone hint me to some examples?
I constructed a try using the example from nls:
#variables are density, conc and Run
#all works fine with nls
DNase1 <- subset(DNase, Run == 1 )
fm2DNase1 <- nls(
2009 Nov 09
1
Parameter info from nls object
Hi!
When checking validity of a model for a large number
of experimental data I thought it to be interesting
to check the information provided by
the summary method programmatically.
Still I could not find out which method to
use to get to those data.
Example (not my real world data, but to show the point):
[BEGIN]
> DNase1 <- subset(DNase, Run == 1)
> fm1DNase1 <- nls(density ~
2003 Oct 28
2
Confidence ellipse for correlation
Hello,
SAS' point and click interface has the option of produce a scatterplot with a
superimposed confidence ellipse for the correlation coefficient. Since I
generally like R so much better, I would like to reproduce this in R. I've
been playing with the ellipse package. In order to have the points and the
ellipse on the same graph I've done the following.
(Load ellipse
2012 Jan 20
1
nobs() and logLik()
Dear all,
I am studying a bit the various support functions that exist for
extracting information from fitted model objects.
From the help files it is not completely clear to me whether the number
returned by nobs() should be the same as the "nobs" attribute of the
object returned by logLik().
If so, then there is a slight inconsistency in the methods for 'nls'
objects with
2005 Apr 19
3
Help with predict.lm
Hi
I have measured the UV absorbance (abs) of 10 solutions of a substance at
known concentrations (conc) and have used a linear model to plot a
calibration graph with confidence limits. I now want to predict the
concentration of solutions with UV absorbance results given in the new.abs
data.frame, however predict.lm only appears to work for new "conc" variables
not new "abs"
2000 Oct 14
2
Access to calculations in nls
Hi,
I would like to be able to access the calculated results from the nls package.
Using the example in R, fm3DNase1 we can reurn certain parts of the
calculations:
> coef(fm3DNase1)
Asym xmid scal
2.345179 1.483089 1.041454
> resid(fm3DNase1)
[1] -0.0136806237 -0.0126806237 0.0089488569 0.0119488569 -0.0025803222
[6] 0.0064196778 0.0026723396 -0.0003276604
2004 Jul 16
1
Does AIC() applied to a nls() object use the correct number of estimated parameters?
I'm wondering whether AIC scores extracted from nls() objects using
AIC() are based on the correct number of estimated parameters.
Using the example under nls() documentation:
> data( DNase )
> DNase1 <- DNase[ DNase$Run == 1, ]
> ## using a selfStart model
> fm1DNase1 <- nls( density ~ SSlogis( log(conc), Asym, xmid, scal ),
DNase1 )
Using AIC() function:
>
2007 May 31
1
predict.nls - gives error but only on some nls objects
Dear list,
I have encountered a problem with predict.nls (Windows XP, R.2.5.0), but I am not sure if it is a bug...
On the nls man page, an example is:
DNase1 <- subset(DNase, Run == 1)
fm2DNase1 <- nls(density ~ 1/(1 + exp((xmid - log(conc))/scal)),
data = DNase1,
start = list(xmid = 0, scal = 1))
alg = "plinear", trace =
2017 Apr 01
6
Intervalos de confianza de la varianza de los residuos en un modelo no lineal.-
Hola amigos,
Supongamos que se quiere ejecutar un modelo no lineal con nls. Pensemos en
el ejemplo de la ayuda:
DNase1 <- subset(DNase, Run == 1)
fm1DNase1 <- nls(density ~ SSlogis(log(conc), Asym, xmid, scal), DNase1)
summary(fm1DNase1)
Aquí se está modelando la densidad óptica de un ensayo relacionada de forma
no lineal (logística) con (el logaritmo) de la concentración de una
proteína.
2024 Mar 05
1
How to invert axis within defined range with ggplot2 scale_y_reverse?
Hello,
I am drawing some data with ggplot2 and would like to reverse the
order of the y axis and set a custom range for it.
I can do the former but when I add the key `limits` to
`scale_y_reverse` I get an error as shows below and, worse, no data
shown in the plot.
How can I properly set a reverse y scale with a defined range in ggplot2?
Thank you
```
A <- rep(c(0, 3, 6, 12, 24), 3)
B <-
2024 Mar 05
1
How to invert axis within defined range with ggplot2 scale_y_reverse?
On 05/03/2024 7:16 a.m., Luigi Marongiu wrote:
> A <- rep(c(0, 3, 6, 12, 24), 3)
> B <- c(rep(0,5), rep(1,5), rep(2,5))
> V <- c(27.5, 27.01, 27.75, 27.98, 27.4, 25.69,
> 26.17, 27.78, 26.08,
> 24.97, 23.18, 21.78, 22.49, 21.85, 22.2)
> df <- data.frame(Conc = A, Time = B, Value = V)
> df$Conc = as.factor(df$Conc)
>
2010 Jul 02
1
conditional dataframe search and find
After some processing...
ct.df <- data.frame(time,conc)
ct.df
gives
time conc
1 0 164.495456
2 1 133.671185
3 2 108.622975
4 3 88.268468
5 4 71.728126
6 5 58.287225
7 6 47.364971
8 7 38.489403
9 8 31.276998
10 9 25.416103
11 10 20.653462
12 11 16.783276
13 12 13.638313
14
2010 Apr 26
1
finite difference scheme for 2D differential equations
Hello everyone,
I am trying to solve 2D differential equations using finite difference
scheme in R. I have been able to work with the equations with only one
spatial dimensions but I want to extend it to the two dimensional problem.
For example i can simulate one dimensional diffusion using a code like the
following. But I want to write a similar code for,say, a two dimensional
diffusion
2008 Apr 30
2
Summary statistics across factor levels
R users,
I intention is to calculate some summary statistics across factor
levels. I know that in Hmisc package there is a summary function which
produces neat summary statistics when using "cross" option. I would
like to produce similar output with N and Missing columns but produce
a data.frame. Is there any built-in function for that?
#example data
install.packages("Hmisc")
2005 Oct 13
1
problems with loop and plot function
Hi all R users,
I have problems with my second loop for drawing the three curves in the
same graphic. I need help please
Thank you in advance
#########################################################################
simulation <- function(k, n){
conc <- seq(0,100,by=0.5)
#choixg <- seq(1, length(conc))
choixg <- rep(0,length(conc))
for (i in 1:length(conc)){
choixg[i] <- (k
2010 Jul 19
1
nls with some coefficients fixed
I'm using nls to fit a variety of different models. Here I use SSgompertz as
an example.
I want the ability to fix one (or more) of the coefficients that would
normally be optimised (e.g. fix b3=0.8).
Examples; based on and using data from example(SSgompertz)
#---------------------
# vanilla call to nls, no coefficients fixed, works fine
nls(density ~ SSgompertz(log(conc), Asym, b2, b3),
2005 Oct 11
2
Problems with plot function
Hello all R users,
My simulation function works correctly, but I have problems with plot
function. You will find the following code using it.
Thank you for your help
##################################################"
simulation <- function(k, n){
conc <- seq(0,10,by=0.5)
#choixg <- seq(1, length(conc))
choixg <- rep(0,length(conc))
for (i in 1:length(conc)){
choixg[i]
2008 Nov 11
2
strsplit (regex)
#how do I break these up into first two letters (RM), number, and then
the last part
#is there an easily accessible regex tutorial on the internet?
v = (structure(1:122, .Label = c("RM215Temp", "RM215SpCond", "RM215DO.Conc",
"RM215Depth", "RM215pH", "RM215ORP", "RM215Turbidity.", "RM215Battery",
"RM215DO.",
2011 Mar 11
2
insertion of a row between individuals
Can someone help with a fairly simple task?
I have a data set where I would like to insert a 0 time event between
individuals:
what I have:
VAR DATE TIME CONC COVAR
1 NOV2 0.25 10 group1
1 NOV2 0.5 20 group1
1 NOV2 1 5 group1
1 NOV2 2 1 group1
1 NOV2 3 0.1 group1
2 NOV2 0.25 10