Displaying 20 results from an estimated 1000 matches similar to: "Ask for help with Error: Object not found"
2010 Sep 20
1
ERROR: Object not found
Dear All,
I am trying to use ode solver "rk4" to solve an ODE system, however, it
keeps saying: Error in eval(expr, envir, enclos) : object "dIN" not found.
The sample codes are enclosed as follows, please help me. Thank you very
much!
rm(list=ls())
library(odesolve)
# The ODE system
ode <- function(t,x,p){
with(as.list(c(x,p)),{
2010 Apr 06
1
estimating the starting value within a ODE using nls and lsoda
All-
I am interested in estimating a parameter that is the starting value for an ODE model.
That is, in the typical combined fitting procedure using nls and lsoda (alternatively rk4), I first defined the ODE model:
minmod <- function(t, y, parms) {
G <- y[1]
X <- y[2]
with(as.list(parms),{
I_t <- approx(time, I.input, t)$y
dG <- -1*(p1 + X)*G +p1*G_b
dX <-
2004 Jan 22
4
Fitting compartmental model with nls and lsoda?
Dear Colleagues,
Our group is also working on implementing the use of R for pharmacokinetic compartmental analysis. Perhaps I have missed something, but
> fit <- nls(noisy ~ lsoda(xstart, time, one.compartment.model, c(K1=0.5, k2=0.5)),
+ data=C1.lsoda,
+ start=list(K1=0.3, k2=0.7),
+ trace=T
+ )
Error in eval(as.name(varName), data) : Object
2003 Oct 07
2
freebsd.org mirroring
Hello all,
Help me please do mirror of freebsd.org.
I got *.sgml through CVSup, installed textproc/docproj.
But when I typed make:
[root@xxx /www/freebsd/]make
===> en
===> en/security
===> en/commercial
===> en/docproj
===> en/news
===> en/news/1993
===> en/news/1996
===> en/news/1997
===> en/news/1998
===> en/news/1999
===> en/news/2000
===> en/news/2001
2009 Jun 12
2
External signal in ODE written in C (using deSolve and approx1?)
Dear list
The deSolve package allows you to specify the model code in C or Fortran.
Thanks to the excellent vignette this works fine. However I have not yet
managed to use forcing functions in C code.
In pure R code this works very well with approxfun() specified outside the
model:
###############################################
#Model
lvml <- function(t, x, parms) {
2010 Sep 16
1
More accurate ODE solver?
Dear All,
I was using rk4 and lsoda to solve a ODE system. However, both of them gave
bad accurate solutions, especially compared with Matlab solver ODE45. For
example, ODE45 gave solutions that can go to a stable level (about 1.6) when
time goes to infinity, however, the solutions from lsoda are decreasing to
very very small (about 1e-130) numbers.
Does R have more accurate ODE solvers as
2004 Jun 10
2
odesolve: lsoda vs rk4
I'm trying to use odesolve for integrating various series of coupled 1st
order differential equations (derived from a system of enzymatic
catalysis and copied below, apologies for the excessively long set of
parameters).
The thing that confuses me is that, whilst I can run the function rk4:
out <- rk4(y=y,times=times,func=func, parms=parms)
and the results look not unreasonable:
2009 Sep 02
2
Configuring Parallel SIP Trunks
Hi,
I'm trying to configure 2 parallel sip trunks between 2 boxes.
However I seem to have the problem that when making a call from Box 2
to Box 1, it sometimes
says authentication failed because it is using the username of the other trunk.
Here's my configuration:
Box 1:
[dp-dp2]
type=peer
username=dp-dp2
secret=mysecret
qualify=yes
host=box.2.ip.address
context=from-internal
[e911-dp2]
2004 Oct 04
3
Beginners problem
Hi,
I'm new to R and have a problem with a little test program (see below).
Why doesn't <<- in function rk4
assign the new value to y so that it is seen in rktest. I thought that
<<- does exactly this. But it seems that I
didn't get it right. I would be very appreciative for an explanation of
that behaviour of <<-. I know how to
write the whole thing so that it
2020 Apr 16
2
Strangeness on X11 screen capture
Hi all,
I am running CentOS 7 on a NUC5CPYB. Intel video:
00:02.0 VGA compatible controller: Intel Corporation Atom/Celeron/Pentium
Processor x5-E8000/J3xxx/N3xxx Integrated Graphics Controller (rev 35)
When I take a screen shot I get "different" things.
I use:
export DISPLAY=:0.0
/usr/bin/xwd -silent -root -out screen; convert screen screen.png
I tried import also for the screen
2008 Apr 09
3
LSODA not accurate when RK4 is; what's going on?
I'm solving the differential equation dy/dx = xy-1 with y(0) = sqrt(pi/2).
This can be used in computing the tail of the normal distribution.
(The actual solution is y(x) = exp(x^2/2) * Integral_x_inf {exp(-t^2/2) dt}
= Integral_0_inf {exp (-xt - t^2/2) dt}. For large x, y ~ 1/x, starting
around x~2.)
I'm testing both lsoda and rk4 from the package odesolve.
rk4 is accurate using step
2010 May 14
2
Subscripting a matrix-like object
I have an S3 class called "tis" (Time Indexed Series) which may or may
not have multiple columns. I have a function "[<-.tis" that I've
reproduced below.
My question is this: inside of "[<-.tis", how can I distinguish between
calls of the form
x[i] <- someValue
and
x[i,] <- someValue ?
In either case, nargs() is 3, and looking at the values
2010 May 14
2
Subscripting a matrix-like object
I have an S3 class called "tis" (Time Indexed Series) which may or may
not have multiple columns. I have a function "[<-.tis" that I've
reproduced below.
My question is this: inside of "[<-.tis", how can I distinguish between
calls of the form
x[i] <- someValue
and
x[i,] <- someValue ?
In either case, nargs() is 3, and looking at the values
2009 May 07
1
data transformation using gamma
Hi R-users,
I have this code to uniformise the data using gamma:
> length(dp1)
[1] 696
> dim(dp1)
[1] 58 12
> dim(ahall)
[1] 1 12
> dim(bhall)
[1] 1 12
> trans_dt <- function(dt,a,b)
+ { n1 <- ncol(dt)
+ n2 <- length(dt)
+ trans <- vector(mode='numeric', length=n2)
+ dim(trans) <- dim(dt)
+ for (i in 1:n1)
+ { dt[,i] <- as.vector(dt[,i])
2009 May 10
4
Partial Derivatives in R
Quick question:
Which function do you use to calculate partial derivatives from a model
equation?
I've looked at deriv(), but think it gives derivatives, not partial
derivatives. Of course my equation isn't this simple, but as an example,
I'm looking for something that let's you control whether it's a partial or
not, such as:
somefunction(y~a+bx, with respect to x,
2006 Mar 26
2
Problem with names() in a plot after ordering a data.frame. Syntax or stupidity?
I am a complete newbie in R .
Using R 2.2.0 Windows XP
This started as a simple exercise to see if I could
produce a simple
Cleveland style dotchart with a line from the '2' axis
to the dot rather
than a continuous line as do "dotchart" and
"dotchart2". At least I could not
find that option.
I got a crude program to work but it includes
unnecessary steps.
2011 Aug 20
4
[PATCH 1/2] Make xencommons a bit more idiomatic
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff -r 8d6edc3d26d2 -r cfb49fe940fd tools/hotplug/Linux/init.d/xencommons
--- a/tools/hotplug/Linux/init.d/xencommons Sat Aug 13 10:14:58 2011 +0100
+++ b/tools/hotplug/Linux/init.d/xencommons Tue Aug 16 16:56:16 2011 -0700
@@ -29,11 +29,9 @@
XENCONSOLED_PIDFILE=/var/run/xenconsoled.pid
shopt -s extglob
-if test
2007 Feb 05
2
Exact matching with grep
Hello,
I would know if it is possible with grep to match a exact string. For
example, I want to match the string "DP2" (and only this) and grep match
"DP2BS" too.
I have sought in the grep help but I didn't find what I want.
2010 Mar 17
9
[Bug 27136] New: blank screen with G98 [Quadro NVS 420] (NV98) dual GPU, 4-head
http://bugs.freedesktop.org/show_bug.cgi?id=27136
Summary: blank screen with G98 [Quadro NVS 420] (NV98) dual GPU,
4-head
Product: xorg
Version: 7.5
Platform: x86-64 (AMD64)
OS/Version: Linux (All)
Status: NEW
Severity: normal
Priority: medium
Component: Driver/nouveau
2012 Dec 04
1
Solve system of equations (nleqslv) only returns origin
I'm solving 4 complex equations simultaneously. Code is below. The code
returns only zero's for the solution though there should also be a non-zero
result. I'm pretty confident that the equations are correct because they
are straight from a published paper and I checked them pretty thoroughly.
The parameter values I used are from the published paper as well. Any
suggestions for how