similar to: differential equation

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

Hi R-users: I have a data formatting question. I have a data set that looks something like this: foo.dat <- cbind(c(NA, 1, 2, 3, 4, 5), c(NA, NA, 0, 10 ,20, 30)) What I have: [,1] [,2] [1,] NA NA [2,] 1 NA [3,] 2 0 [4,] 3 10 [5,] 4 20 [6,] 5 30 I want to line up the columns by the first value that is not NA. Like so: [,1] [,2] [1,] 1 0 [2,]

I am an initial user of R. Could you give me some explanations or examples on how to solve the first order differential equations by the first-order Runge-Kutta method? Thank you very much Kind regards

Dear All A new non-linear mixed-effects modelling package for R called nlmeODE is now available at www.cran.r-project.org and http://nlmeODE.sourceforge.net. It combines Pinheiro and Bates' NLME library in R with an ordinary differential equations (ODE) solver thereby enabling the use of differential equations in population PK/PD modelling. It includes several PK examples such as one- and

i am trying to solve a partial differential equation analytically(PDE) in R . i have found some functions that do the stuff numerically. But that will not meet my purpose. is there any function to solve PDE analytically. please help. -- View this message in context: http://r.789695.n4.nabble.com/analytical-solution-of-partial-differential-equation-tp4291618p4291618.html Sent from the R help

Hi, I am using package deSolve to run some ordinary differential equations (ODE) as part of a mathematical modeling project. I have solved for the following equilibrium states: Seq1<-a*(1-Neq1)/(f*Veq1+m+d) Ceq1<-(f*Seq1*Veq1+g*Ieq1+r*(1-Neq1)-b1*Veq1*Ieq1)/(b2+m+d+g) Ieq1<-(-b2*Ceq1)-r*(1-Neq1)/(b1*Veq1-g-u) Veq1<-o*(Ceq1+Ieq1)/e I want to take the differential of both sides of

This is applicable to either using optim or the differential equation solver or any similar solver Suppose I want to use the differential equation solver and this is my code d<-y[2] vdpol<-function(t,y) { list(c(1, d, 3, 4 ) } stiff<-ode(y=rep(0,4),times=c(0,1),func=dvdpol,parms=1) The thing is I want d to be composed of one of state variables in the

Hello, I am trying to find the analytical solution to this differential equation dR/dt = k1*R (1-(R/Rmax)^k2); R(0) = Ro k1, k2, and Rmax are parameters that need to fitted, while Ro is the baseline value (which can be fitted or fixed). The response (R) increases initially at an exponential rate governed by the rate constant k1. Response has a S-shaped curve as a function of time and it

I haven't used r in quite a while but would like to get back into it. I have a problem that I would like to solve with r. I have some multinomial data that looks to follow an asymmetric sigmoidal growth pattern. Solving a multinomial gompertz partial differential equation in r is what I’m after. Would anyone be able to provide me the code and packages to do something like this? Regards,

Hello, I want to know if there are some functions or packages to solve differential and integral equation using R. Thanks. Shao chunxuan. [[alternative HTML version deleted]]

To whom it may concern, I am a student at Macaleste College, and next semester Macalester is going to offer a course for CellBio that is mainly statistically based. For the most part the students will be using R for analysis. The problem is there will be some simple differential equations for the students to solve. The committee that in charge of the classes corriculam would like only to

Hello list I have a theoretical differential equation model (two coupled differential equations) describing the acidification of dairy cultures in milk: dX/dt = f(H, param)*X dH/dt = g(param)*dX/dt pH = -log10(H) I also have actual data of the same. I would like to estimate the parameters of the theoretical model from real data, but don't know how to go about it in R (I'm fairly new

Hello, I am trying to find the analytical solution to this differential equation dR/dt = k1*(R^k2)*(1-(R/Rmax)); R(0) = Ro k1 and k2 are parameters that need to fitted, while Ro and Rmax are the baseline and max value (which can be fitted or fixed). The response (R) increases initially at an exponential rate governed by the rate constants k1 and k2. Response has a S-shaped curve as a function

Hello! I would like to know if R can solve Differential Equations... I don't think so because, in my point, I see R like a Statistical System, not a Math System. Am I wrong? Thank you very much. M??rcio de Medeiros Ribeiro Graduando em Ci??ncia da Computa????o Departamento de Tecnologia da Informa????o - TCI Universidade Federal de Alagoas - UFAL Macei?? - Alagoas - Brasil Projeto CoCADa

Hi, I would like to plot the following equation: dF(x)/dx=(k1+k2F(x))(1-F(x)) where k1 and k2 are parameters that I have estimated already. How can I plot the curve in R? Thanks! Montserrat Rue Universitat de Lleida (Spain) [[alternative HTML version deleted]]

Hi, Does somebody knows of the existence of a library of functions for solving differential equations, I need a solver for a system of non linear first order differential equations. I think there was something in IMSL but that was a long time ago and probably there are some new algorithms in the new now. Thanks for any pointers. . R. Heberto Ghezzo Ph.D. Meakins-Christie Labs McGill

Dear R-community My ODE problems looks as follows: (1) dA/dt = u*A - v*B (2) dB/dt = v*B - u*A where u is a constant, and v=k*t (k=constant, t=time) Does anybody knows a good function/procedure of solving? Should one involve the equation (3) dv/dt = k? Thanks for your support. -- Dominik Heinzmann Master of Science in Mathematics, EPFL Ph.D. student in Biostatistics Institute of Mathematics

Hello, I am having troubles with heat conduction problem. Below is the given information. Should I move forward with this problem like any other 1-D PDE? ?T/?t = a* (?^2T/?x^2) I.C. For t = 0 and 0 ? x ? 10, T = 0 ?C B.C. For x = 0 cm and all t , T = 100?C For x = 10 cm and all t , T = 0 ?C The thermal diffusivity is a = 2.0 cm^2 /s. I also added what I have for code in R. Any help will

Hi, I'd like to know whether R is capable to assess parameters in a model describing the kinetic of a pollutant adsorption onto activated carbon. A common relation is for instance the Adam-Bohart-Thomas' one: dx/dt = K1 * (qm-x)*C - K2x where {K1,K2} are the unknown paramters and {qm,C} are known parameters Of course I get experimental data sets of measured x as a function of time.

Hello List, Can you recommend me if odeSolve can handle stiff delay differential equations with discontinuities? Or any other package? Best, -m