Displaying 20 results from an estimated 3000 matches similar to: "fit to spike with exponential decay : optim() question"
2001 Dec 14
1
nls fit to exponential decay with unknown time origin
I'm trying to use nls() to fit an exponential decay with an unknown offset
in the time (independent variable). (Perhaps this is inherently very
difficult?).
> decay.pl <- nls (amp ~ expn(b0,b1,tau,t0,t), data = decay,
+ start = c(b0=1, b1=7.5, tau=3.5, t0=0.1), trace=T)
Error in nlsModel(formula, mf, start) : singular gradient matrix at
initial parameter estimates
2001 Sep 01
2
interpolation and numerical differentiation in R ?
Hi,
I'm trying to determine if R is useful to me. I've browsed 'The Basics of
S and S-Plus' (Krause & Olson), and like the logic of the language.
However, I don't see an easy way to do things like this:
* given a set of observations (x,y) (x and y equal-length vectors), and a
2nd set of abscissas x2, interpolate y at the new abscissas x2. (for now,
I don't really
2001 Oct 05
1
nls() fit to a lorentzian - can I specify partials?
First, thanks to all who helped me with my question about rescaling axes
on the fly. Using unlist() and range() to set the axis ranges in advance
worked well. I've since plotted about 300 datasets with relative ease.
Now I'm trying to fit a lossy oscillator resonance to (the square root of)
a lorentzian (testframe$y is oscillator amplitude, testframe$x is drive
frequency):
lorentz
2002 Jun 04
4
par(xaxp)
I think this is a bug; at least this behavior is not documented in plot
or plot.default.
plot.default resets xaxp, and leaves xaxp reset when it exits:
par(xaxp=c(0,1,4))
print(par("xaxp"))
plot(c(0,1),c(0.2,0.3))
print(par("xaxp"))
R. Woodrow Setzer, Jr. Phone:
(919) 541-0128
Experimental Toxicology Division
2011 Jan 15
1
Weighted least squares regression for an exponential decay function
Hello,
I have a data set of data which is best fit by an exponential decay
function. I would like to use a nonlinear weighted least squares regression.
What function should I be using?
Thank you!
[[alternative HTML version deleted]]
2009 Nov 09
0
Testing treatment effects on exponential decay models
Hello all:
I would like to test whether there are treatment effects on decomposition
rate, and I would like to inquire about the best, most appropriate means
using R.
I have plant decomposition data that is generally considered to follow an
exponential decay model as follows:
Wt = Wi * exp(-k * t)
Where Wt and Wi are the weights of the plant material at time t and 0,
respectively. k is a
2018 Apr 06
2
Obtain gradient at multiple values for exponential decay model
> Sent: Friday, April 06, 2018 at 4:53 AM
> From: "Jeff Newmiller" <jdnewmil at dcn.davis.ca.us>
> To: "g l" <gnulinux at gmx.com>
> coef( graphmodeld )
>
coef(graphmodelp)
Error: $ operator is invalid for atomic vectors
A quick search engine query revealed primarily references to the dollar sign ($) operator which does not seem relevant to this
2018 Apr 06
0
Obtain gradient at multiple values for exponential decay model
You did not try my suggestion. You tried David's, which has a leftover mistake from your guesses about what the argument to coef should be.
--
Sent from my phone. Please excuse my brevity.
On April 6, 2018 3:30:10 AM PDT, g l <gnulinux at gmx.com> wrote:
>> Sent: Friday, April 06, 2018 at 4:53 AM
>> From: "Jeff Newmiller" <jdnewmil at dcn.davis.ca.us>
2018 Apr 06
1
Obtain gradient at multiple values for exponential decay model
> Sent: Friday, April 06, 2018 at 1:44 PM
> From: "Jeff Newmiller" <jdnewmil at dcn.davis.ca.us>
>
> You did not try my suggestion. You tried David's, which has a leftover mistake from your guesses about what the argument to coef should be.
Yes, sorry for the mistake.
coef(graphmodeld)
(Intercept) graphdata[, 1]
4.513544204 -0.006820623
This corresponds
2018 Apr 06
0
Obtain gradient at multiple values for exponential decay model
> On Apr 6, 2018, at 3:43 AM, g l <gnulinux at gmx.com> wrote:
>
>> Sent: Friday, April 06, 2018 at 5:55 AM
>> From: "David Winsemius" <dwinsemius at comcast.net>
>>
>>
>> Not correct. You already have `predict`. It is capale of using the `newdata` values to do interpolation with the values of the coefficients in the model. See:
2018 Apr 06
2
Obtain gradient at multiple values for exponential decay model
> Sent: Friday, April 06, 2018 at 5:55 AM
> From: "David Winsemius" <dwinsemius at comcast.net>
>
>
> Not correct. You already have `predict`. It is capale of using the `newdata` values to do interpolation with the values of the coefficients in the model. See:
>
> ?predict
>
The ? details did not mention interpolation explicity; thanks.
> The
2018 Apr 07
0
Obtain gradient at multiple values for exponential decay model
I have never found the R symbolic differentiation helpful because my
functions are typically quite complicated, but was prompted by Steve
Ellison's suggestion to try it out in this case:
################# reprex (see reprex package)
graphdta <- read.csv( text =
"t,c
0,100
40,78
80,59
120,38
160,25
200,21
240,16
280,12
320,10
360,9
400,7
", header = TRUE )
nd <- c( 100, 250,
2013 Dec 03
1
Outbound traffic spike every 30 minutes
Is inbound or outbound?
What port?
tcp or udp?
------Mensaje original------
De: Bowie Bailey
Remitente: centos-bounces at centos.org
Para: CentOS mailing list
Responder a: CentOS mailing list
Asunto: [CentOS] Outbound traffic spike every 30 minutes
Enviado: 3 de dic de 2013 19:36
Since Sunday morning, one of my CentOS servers has been generating a
small spike of outbound traffic every 30
2001 Oct 01
3
can I add to a plot and auto-re-scale axes?
(I'm new to R)
Is there a way to add data to an existing plot, and have the plot axes
rescaled automatically (i.e. if the new data lie outside the current
axes) ?
If not, how can I specify multiple datasets at once, so the axes are
scaled to accomodate all sets?
Details:
(Am I using R's data structures in a reasonable way?)
I have many small datasets taken under different
2018 Apr 06
3
Obtain gradient at multiple values for exponential decay model
> On Apr 6, 2018, at 8:03 AM, David Winsemius <dwinsemius at comcast.net> wrote:
>
>
>> On Apr 6, 2018, at 3:43 AM, g l <gnulinux at gmx.com> wrote:
>>
>>> Sent: Friday, April 06, 2018 at 5:55 AM
>>> From: "David Winsemius" <dwinsemius at comcast.net>
>>>
>>>
>>> Not correct. You already have
2013 Dec 03
1
Outbound traffic spike every 30 minutes
Since Sunday morning, one of my CentOS servers has been generating a
small spike of outbound traffic every 30 minutes (X:00 and X:30). It's
not enough traffic to really cause any notice except for the fact that
it is a very regular pattern and it started abruptly at midnight Sunday.
This server is used for mail (Courier-MTA), and DNS (Bind). I cannot
find anything unusual in either of
2008 Dec 24
1
dovecot-auth Temporary But Frequent CPU Spike
Hi.. I am setting up a new server (2GHz CPU, Ubuntu 8.10) and am using
dovecot for an IMAP server. I have installed dovecot 1.1.4 and
Squirrelmail 1.4.15. sudo dovecot -n shows this:
# 1.1.4: /etc/dovecot/dovecot.conf
log_timestamp: %Y-%m-%d %H:%M:%S
protocols: imap
login_dir: /var/run/dovecot/login
login_executable: /usr/lib/dovecot/imap-login
login_process_per_connection: no
2008 Sep 10
0
STAR (Spike Train Analysis with R) uploaded on CRAN
Hi all,
I've uploaded STAR (Spike Train Analysis with R) on CRAN two days ago.
The package is designed to analyze neuronal spike (action potential)
trains. It uses S3 classes and methods and makes heavy use of other
CRAN packages like gss, R2HTML, mgcv, survival.
* Analysis of both spontaneous and stimulus evoked activity is
implemented for single neuron spike trains as well as for many
2008 Sep 10
0
STAR (Spike Train Analysis with R) uploaded on CRAN
Hi all,
I've uploaded STAR (Spike Train Analysis with R) on CRAN two days ago.
The package is designed to analyze neuronal spike (action potential)
trains. It uses S3 classes and methods and makes heavy use of other
CRAN packages like gss, R2HTML, mgcv, survival.
* Analysis of both spontaneous and stimulus evoked activity is
implemented for single neuron spike trains as well as for many
2013 Dec 03
0
Outbound traffic spike every 30 minutes
Sorry...
Try with some tool to see what type of traffic.
(Munin,cacti,ganglia, etc)
Is in your lan?
Diego Sanchez
Sent from my mobile
-----Original Message-----
From: diegors at gmail.com
Date: Tue, 3 Dec 2013 20:42:39
To: CentOS mailing list<centos at centos.org>
Reply-To: diegors at gmail.com
Subject: Re: [CentOS] Outbound traffic spike every 30 minutes
Is inbound or outbound?
What