VecDecomRem: Vector decomposition and remainder fields

In QPot: Quasi-Potential Analysis for Stochastic Differential Equations

Description

This function calculates the remainder field.

Usage

VecDecomRem(surface, x.rhs, y.rhs, x.bound, y.bound)

Arguments

surface	matrix output from QPGlobal or QPotential.
x.rhs	a string containing the right hand side of the equation for x.
y.rhs	a string containing the right hand side of the equation for y.
x.bound	the x boundaries denoted at c(minimum, maximum).
y.bound	the y boundaries denoted at c(minimum, maximum).

Value

returns an array of the remainder vector field. The array has three dimensions with the respective lengths of the columns of the surface, the rows of the sruface, and the number of variables (always 2). The two variables are the x-remainder and y-remainder.

Examples

# First, the system of equations
	equationx <- "1.54*x*(1.0-(x/10.14)) - (y*x*x)/(1.0+x*x)"
	equationy <- "((0.476*x*x*y)/(1+x*x)) - 0.112590*y*y"

# Second, shared parameters for each quasi-potential run
	xbounds <- c(-0.5, 10.0)
	ybounds <- c(-0.5, 10.0)
	xstepnumber <- 150
	ystepnumber <- 150

# Third, first local quasi-potential run
	xinit1 <- 1.40491
	yinit1 <- 2.80808
	storage.eq1 <- QPotential(x.rhs = equationx, x.start = xinit1, 
	x.bound = xbounds, x.num.steps = xstepnumber, y.rhs = equationy, 
	y.start = yinit1, y.bound = ybounds, y.num.steps = ystepnumber)

# Fourth, second local quasi-potential run
	xinit2 <- 4.9040
	yinit2 <- 4.06187
	storage.eq2 <- QPotential(x.rhs = equationx, x.start = xinit2, 
	x.bound = xbounds, x.num.steps = xstepnumber, y.rhs = equationy, 
	y.start = yinit2, y.bound = ybounds, y.num.steps = ystepnumber)

# Fifth, determine global quasi-potential 
	unst.x <- c(0, 4.2008)
	unst.y <- c(0, 4.0039)
	ex1.global <- QPGlobal(local.surfaces = list(storage.eq1, storage.eq2), 
	unstable.eq.x = unst.x, unstable.eq.y = unst.y, x.bound = xbounds, 
	y.bound = ybounds)

# Sixth, create remainder field
VDR <- VecDecomRem(surface = ex1.global, x.rhs = equationx, y.rhs = equationy, 
	x.bound = xbounds, y.bound = ybounds)	

QPot documentation built on May 2, 2019, 2:34 p.m.