Displaying 20 results from an estimated 500 matches similar to: "deSolve output"
2011 Jan 25
1
deSolve: Problem solving ODE including modulo-operator
I have a problem integrating the 'standard map' (
http://en.wikipedia.org/wiki/Standard_map
http://en.wikipedia.org/wiki/Standard_map ) with deSolve:
By using the modulo-operator '%%' with 2*pi in the ODEs (standardmap1), the
resulting values of P and Theta, should not be greater than 2pi. Because
this was not the case, i was thinking that the function 'ode' has some
2011 Aug 16
1
deSolve, extracting variable values from inside ode function
I'm just getting to grips with using ode function and have used the
examples and vignettes to produce a small model of a one-pool,
michaelis-menten, enzyme kinetic reaction. The rate of flux of substrate
into pool A is constant (fluxoa) however the rate of flux out of pool A
is controlled by the HMM equation (v = Vmax/ ( 1 + (Km / Concentration A
)) ). This function works fine and
2013 Feb 21
1
using and event in deSolve
Hi All
Having been pointed the use of events and roots in deSolve, I was able to
implement the Izchikevich model of spiking neurons. However, I'm not too
sure of defining the event. The deSolve documentation says:
An event is triggered when the ball hits the ground (height = 0) Then
velocity (y2) is reversed
and reduced by 10 percent. The root function, y[1] = 0, triggers the event:
>
2010 Jun 07
1
Desolve package: How to pass thousand of parameters to C compiled code?
Hi,
I have used DeSolve package for my ODE problem regarding infectious disease transmission and currently am trying to pass lots (roughly a thousand) of model parameters to the C compiled model (I have to use C compiled code instead of R code purely because of the speed).
I can't go define it one by one as it gonna take ages to finish and also quite difficult to revise. I have read the
2012 Feb 03
1
Logistic population growth and deSolve
Hello, I am new to R and I am having problems trying to model logistic
population growth with the deSolve package. I would like to run the model
for four populations with the same initial population and carrying capacity
but with different growth rates and put the results into a data frame. When
I run the following lines of code I get unexpected results from "output" but
the format is
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) {
2013 Jun 18
1
deSolve question
Dear All
wonder if you could provide some insights on the following: currently I have this code which produces the expected results:
require(deSolve)
pars <- list(k = 0.08,v=15)
intimes <- c(0,0.5,12)
input <- c(800,0,0)
forc <- approxfun(intimes, input, method="constant", rule=2)
derivs <- function(t, state, pars) {
inp <- forc(t)
dy1 <- - pars$k * state[1]
2017 Nov 29
1
DeSolve Package and Moving Average
Dear all,
I am using the DeSolve Package to simulate a system dynamics model. At the problematic point in the model, I basically want to decide how many products shall be produced to be sold. In order to determine the amount a basic forecasting model of using the average of the last 12 time periods shall be used. My code looks like the following.
? [?]
# Time units in month
START<-0;
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,
2009 Jun 29
0
new version of package deSolve on CRAN
Dear R users,
an improved version of package deSolve (version 1.3) is now available on
CRAN. deSolve, the successor of R package odesolve, is a package to
solve initial value problems (IVP) of:
- ordinary differential equations (ODE),
- differential algebraic equations (DAE) and
- partial differential equations (PDE).
The implementation includes stiff integration routines based on the
ODEPACK
2009 Jun 29
0
new version of package deSolve on CRAN
Dear R users,
an improved version of package deSolve (version 1.3) is now available on
CRAN. deSolve, the successor of R package odesolve, is a package to
solve initial value problems (IVP) of:
- ordinary differential equations (ODE),
- differential algebraic equations (DAE) and
- partial differential equations (PDE).
The implementation includes stiff integration routines based on the
ODEPACK
2012 Jan 30
2
ode() tries to allocate an absurd amount of memory
Hi there R-helpers:
I'm having problems with the function ode() found in the package deSolve.
It seems that when my state variables are too numerous (>33000 elements),
the function throws the following error:
Error in vode(y, times, func, parms, ...) :
cannot allocate memory block of size 137438953456.0 Gb
In addition: Warning message:
In vode(y, times, func, parms, ...) : NAs
2018 May 31
0
Help in dynamic simulation using deSolve
Hi R help,
I wanted to simulate two pool model (A&B) using deSolve package for time 0 to 12 by 1.? Initial values of the state variables are A=5, B=3. The fluxes are as follows1) Flux into A= 5 units per unit time?2) Flux from A to B= 0.33) Flux out of A=0.1?4) Flux from B to A=0.35) Flux out of B=0.3
Here is the R code I compiled to estimate the size of A and B and graph the output
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 Apr 18
2
Event-triggered change in value with a time-delay
Hello,
I am solving a set of ODEs using deSolve and have run into a problem I
would appreciate some advice on. One of the parameters (m) in the ODEs
changes between two states when one of the variables (D) crosses a
threshold (D_T) for the first time in either direction. Additionally, when
the variable crosses the threshold (either by increasing or decreasing),
there is a time delay (delay)
2018 Apr 18
0
Event-triggered change in value with a time-delay
> On Apr 18, 2018, at 1:04 AM, Hannah Meredith <hrmeredith12 at gmail.com> wrote:
>
> Hello,
>
> I am solving a set of ODEs using deSolve and have run into a problem I
> would appreciate some advice on. One of the parameters (m) in the ODEs
> changes between two states when one of the variables (D) crosses a
> threshold (D_T) for the first time in either direction.
2011 Oct 03
0
deSolve - Function daspk on DAE system - Error (Vince)
Vince,
When that happens, one possible reason is that your DAE is of index > 1,
which cannot be solved by daspk.
The solver radau, also from deSolve can handle DAEs up to index 3, but
you need to rewrite the problem in the form M*y' = f(x,y), where M is a
mass matrix.
If you do that for your problem, and solve it with radau, then radau
complains that the "matrix is repeatedly
2012 Apr 25
1
Using apply() with a function involving ode()
Hello,
I am trying to get the output from the numerical simulation of a system
of ordinary differential equations for a range of values for three
parameters. I am using the ode() function (deSolve package) to run the
numerical simulation and apply() to run the simulation function for each
set of parameter values. I am having trouble getting the apply()
function to work.
Here is an
2011 Oct 02
0
deSolve - Function daspk on DAE system - Error
I'm getting this error on the attached code and breaking my head but can't
figure it out. Any help is much appreciated. Thanks, Vince
CODE:
library(deSolve)
Res_DAE=function(t, y, dy, pars) {
with(as.list(c(y, dy, pars)), {
res1 = -dS -dES-k2*ES
res2 = -dP + k2*ES
eq1 = Eo-E -ES
eq2 = So-S -ES -P
return(list(c(res1, res2, eq1, eq2)))
})
}
pars <- c(Eo=0.02,
2010 Jul 16
1
Creating symbolic expressions in R
Hello,
I'm trying to do some differential equation modeling in R using the
package 'deSolve.' Briefly, I'm trying to use the law of mass action
(the details of which aren't really important) to structure a vector
of rate equation which will be passed into an ODE function and solved
with associated functions from 'deSolve.' Roughly what this entails
is scanning