bvpSolve (version 1.1)

plot.bvpSolve: Plot Method for Output of bvpSolve

Description

Plot the output of boundary value solver routines.

Usage

## S3 method for class 'bvpSolve':
plot(x, which = 1:(ncol(x)-1), ask = NULL, ...)

Arguments

x

the output of bvpSolve, as returned by the boundary value solvers, and to be plotted.

which

the name(s) or the index to the variables that should be plotted. Default = all variables.

ask

logical; if TRUE, the user is asked before each plot, if NULL the user is only asked if more than one page of plots is necessary and the current graphics device is set interactive, see

...

additional graphics arguments passed to plot.default

Details

Based on the S3-method of package bvpSolve. The number of panels per page is automatically determined up to 3 x 3 (par(mfrow=c(3, 3))). This default can be overwritten by specifying user-defined settings for mfrow or mfcol. Other graphical parameters can be passed as well. Parameters xlab and ylab are vectorized, so it is possible to assign specific axis labels to individual plots.

Examples

## =============================================================================
## The example MUSN from Ascher et al., 1995.
## Numerical Solution of Boundary Value Problems for Ordinary Differential
## Equations, SIAM, Philadelphia, PA, 1995.
##
## The problem is
##      u' =  0.5*u*(w - u)/v
##      v' = -0.5*(w - u)
##      w' = (0.9 - 1000*(w - y) - 0.5*w*(w - u))/z
##      z' =  0.5*(w - u)
##      y' = -100*(y - w)
##   on the interval [0 1] and with boundary conditions:
##      u(0) = v(0) = w(0) = 1,  z(0) = -10,  w(1) = y(1)
## =============================================================================

musn <- function(t,Y,pars)
{
  with (as.list(Y),
  {
   du=0.5*u*(w-u)/v
   dv=-0.5*(w-u)
   dw=(0.9-1000*(w-y)-0.5*w*(w-u))/z
   dz=0.5*(w-u)
   dy=-100*(y-w)
   return(list(c(du,dv,dw,dy,dz)))
  })
}

#--------------------------------
# Residuals
#--------------------------------
res  <- function (Y,yini,pars)  with (as.list(Y), w-y)

#--------------------------------
# Initial values; y= NA= not available
#--------------------------------

init <- c(u=1,v=1,w=1,y=NA,z=-10)
sol  <-bvpshoot(y= init, x=seq(0,1,by=0.05), func=musn,
           yend=res, guess=1, atol=1e-10, rtol=0)

mf <- par("mfrow")
plot(sol)
par(mfrow=mf)