Displaying 20 results from an estimated 200 matches similar to: "matrix bending"
2004 Dec 03
1
Getting R to emit an image file as a pipe or Base64 strea m: Mac OSX 10.3 - R 2.0.1
> From: Yuandan Zhang
> 
> If you want to call R from perl, why don't you do a simple 
> system call like:
> 
> $callR="/usr/loca/bin/R CMD BATCH plotscript.R";
> system ($callR);
> 
> It is not necessary to start X display if anything can be 
> done in background
But the problem is jpeg()/png() are not available unless an X display is
available to the
2005 Jul 19
2
Michaelis-menten equation
Dear R users:
   I encountered difficulties in michaelis-menten equation. I found 
that when I use right model definiens, I got wrong Km vlaue, 
and I got right Km value when i use wrong model definiens. 
The value of Vd and Vmax are correct in these two models. 
#-----right model definiens--------
PKindex<-data.frame(time=c(0,1,2,4,6,8,10,12,16,20,24),
      
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
2001 May 11
1
lsoda
I am running R 1.2.3 with ESS5.1.18 with Windows 98.
I am trying to use lsoda in the odesolve apckage and am having problems.
Question:
The return value of the function of the system of ode's has to be a list
that includes first, the ode's and second, "a vector
          (possibly with a `names' attribute) of global values that are
required at each point in `times'."
I
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:
2004 Oct 06
1
Foreign code problem
Hello,
I wanted to test the odesolve package and tried to use compiled C-code.
But when I do:
erg <- lsoda(y, times, "mond", parms, rtol, atol, tcrit=NULL, jacfunc=NULL,
               verbose=FALSE, dllname="mond", hmin=0, hmax=Inf)
I get the error message:
Error in lsoda(y, times, "mond", parms, rtol, atol, tcrit = NULL,             
               jacfunc =
2009 Jun 11
3
deSolve question
Dear All,
I like to simulate a physiologically based pharmacokinetics model using R
but am having a problem with the daspk routine.
The same problem has been implemented in Berkeley madonna and Winbugs so
that I know that it is working. However, with daspk it is not, and the
numbers are everywhere!
Please see the following and let me know if I am missing something...
Thanks a lot in advance,
2006 Jul 21
3
positive semi-definite matrix
I have a covariance matrix that is not positive semi-definite matrix and I
need it to be via some sort of adjustment.  Is there any R routine or
package to help me do this?
Thanks, Roger
	[[alternative HTML version deleted]]
2005 Nov 06
1
Problem defining a system of odes as a C library with lsoda
I have been trying to make use of the odesolve library on my 
university's Linux grid - currently R version 2.0.1 is installed and 
the system runs 64-bit Scientific Linux based on Redhat. I cannot seem 
to get lsoda working when I define the model as a shared C library. For 
example, the following snippet uses the mymod.c example bundled with 
the package:
### START
rm(list=ls())
2002 Jan 07
3
cluster - clusplot.default (PR#1249)
The following code in clusplot.default (package cluster) is in error:
x1 <- cmdscale(x, k = 2, eig = TRUE)
        var.dec <- sum(x1$eig)/sum(diag(x1$x))
        if (var.dec < 0) 
            var.dec <- 0
        if (var.dec > 1) 
            var.dec <- 1
        x1 <- x1$points
x1 has components with names "points" and "eig", not "x", so 
2020 Sep 11
2
[cfe-dev] Phabricator -> GitHub PRs?
On Fri, Sep 11, 2020 at 6:53 PM David Blaikie <dblaikie at gmail.com> wrote:
> Is there any observable difference between "Squash and Merge" or "Rebase
> and Merge" when "enforce linear history" is enabled, then?
>
"Squash and Merge" will only generate one commit.
>
> On Fri, Sep 11, 2020 at 3:45 PM Stephen Neuendorffer via llvm-dev
2010 Feb 18
1
R-commands for MDS
Hello
I am using the following command but not able to text the values on the graph can
someone please make suggestions for improvement
 #here is the command
loc_mds <- cmdscale(dist.r, k = 7, eig = TRUE)
 loc_mds$eig
sum(abs(loc_mds$eig[1:2]))/sum(abs(loc_mds$eig))
sum((loc_mds$eig[1:2])^2)/sum((loc_mds$eig)^2)
x <-loc_mds$points[,1]
y <-loc_mds$points[,2]
plot(x, y,
2012 Nov 26
1
Help on function please
Dear All,
 
I could use a bit of help here, this function is hard to figure out (for me at least) I have the following so far:
 
PKindex<-data.frame(Subject=c(1),time=c(1,2,3,4,6,10,12),conc=c(32,28,25,22,18,14,11))
Dose<-200
Tinf <-0.5
 
defun<- function(time, y, parms) { 
 dCpdt <- -parms["kel"] * y[1] 
 list(dCpdt) 
 } 
modfun <- function(time,kel, Vd) {  
 out <-
2013 Apr 21
1
lsoda question from deSolve package
Dear List,
Wonder if you have some thoughts on the following question using lsoda in desolve:
I have the following data and function:
require(deSolve)
times <- c(0:24)
tin  <- 0.5
D <- 400
V    <- 26.3
k <-0.056
k12  <- 0.197118
k21  <- 0.022665
yini <- c(dy1 = 0,dy2 = 0)
 events <- data.frame(var = "dy1",time = c(10,15),value = c(200,100),method =
2018 Jul 30
2
trace in uniroot() ?
In looking at rootfinding for the histoRicalg project (see gitlab.com/nashjc/histoRicalg),
I thought I would check how uniroot() solves some problems. The following short example
ff <- function(x){ exp(0.5*x) - 2 }
ff(2)
ff(1)
uniroot(ff, 0, 10)
uniroot(ff, c(0, 10), trace=1)
uniroot(ff, c(0, 10), trace=TRUE)
shows that the trace parameter, as described in the Rd file, does not seem to
be
2008 Apr 01
1
superimpose histogram on biplot
Hi all,
I've been trying to figure out how to superimpose a histogram on a  
biplot that shows the relative contribution of each axis.  I have  
been using the NIPALS function (http://biomserv.univ-lyon1.fr/~dray/ 
files/softwares/nipals.R) to run principal component analyses.  Here  
is a toy example.
source("http://biomserv.univ-lyon1.fr/~dray/files/softwares/nipals.R")
2008 Nov 21
1
lsoda warning "too much accuracy requested"
Dear list -
 
Does anyone have any ideas / comments about why I am receiving the following
warning when I run lsoda:
 
1:  lsoda--  at t (=r1), too much accuracy requested in: lsoda(start, times,
model, parms) 
2:       for precision of machine..  see tolsf (=r2) in: lsoda(start, times,
model, parms)
 
I have tried changing both rtol and atol but without success.  I saw the
thread in the
2005 Dec 04
1
Understanding nonlinear optimization and Rosenbrock's banana valley function?
GENERAL REFERENCE ON NONLINEAR OPTIMIZATION?
	  What are your favorite references on nonlinear optimization?  I like 
Bates and Watts (1988) Nonlinear Regression Analysis and Its 
Applications (Wiley), especially for its key insights regarding 
parameter effects vs. intrinsic curvature.  Before I spent time and 
money on several of the refences cited on the help pages for "optim", 
2006 Dec 05
1
Cummulative Variance in Correspondence Analysis (ADE4)
Hi all:
How can I calculate the cumulative variance (or variance for each component)
in correspondence analysis?
If were possible in ADE4 package
Thank you
 -- Antonio Punzón Merino
 O__---- Instituto Español de Oceanografía
c/ /'_ --- Centro Oceanográfico de Santander
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~~~~~~~~~~ 39004-Santander; Spain
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Fax: +34
2003 Apr 03
2
Matrix eigenvectors in R and MatLab
Dear R-listers
Is there anyone who knows why I get different eigenvectors when I run
MatLab and R? I run both programs in Windows Me. Can I make R to produce
the same vectors as MatLab?
#R Matrix
PA9900<-c(11/24 ,10/53 ,0/1 ,0/1 ,29/43 ,1/24 ,27/53 ,0/1 ,0/1 ,13/43
,14/24 ,178/53 ,146/244 ,17/23 ,15/43 ,2/24 ,4/53 ,0/1 ,2/23 ,2/43 ,4/24
,58/53 ,26/244 ,0/1 ,5/43)
#R-syntax