EulerRichardson-class: EulerRichardson ODE solver class

Description Usage Arguments Examples

Description

EulerRichardson ODE solver class

EulerRichardson generic

EulerRichardson constructor ODE

Usage

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
EulerRichardson(ode, ...)

## S4 method for signature 'EulerRichardson'
init(object, stepSize, ...)

## S4 method for signature 'EulerRichardson'
step(object, ...)

## S4 method for signature 'ODE'
EulerRichardson(ode, ...)

Arguments

ode

an ODE object

...

additional parameters

object

internal passing object

stepSize

the size of the step

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
# ++++++++++++++++++++++++++++++++++++++++++++++++++      example: PendulumApp.R
# Simulation of a pendulum using the EulerRichardson ODE solver

suppressPackageStartupMessages(library(ggplot2))

importFromExamples("Pendulum.R")      # source the class

PendulumApp <- function(verbose = FALSE) {
    # initial values
    theta <- 0.2
    thetaDot <- 0
    dt <- 0.1
    pendulum <- Pendulum()
    # [email protected][3] <- 0      # set time to zero, t = 0
    pendulum <- setState(pendulum, theta, thetaDot)
    pendulum <- setStepSize(pendulum, dt = dt) # using stepSize in RK4
    pendulum@odeSolver <- setStepSize(pendulum@odeSolver, dt) # set new step size
    rowvec <- vector("list")
    i <- 1
    while (getState(pendulum)[3] <= 40)    {
        rowvec[[i]] <- list(t        = getState(pendulum)[3],    # time
                            theta    = getState(pendulum)[1], # angle
                            thetadot = getState(pendulum)[2]) # derivative of angle
        pendulum <- step(pendulum)
        i <- i + 1
    }
    DT <- data.table::rbindlist(rowvec)
    return(DT)
}
# show solution
solution <- PendulumApp()
plot(solution)

f0nzie/rODE documentation built on May 14, 2019, 10:34 a.m.