vectorfield: Add a Vector Field to a Plot

In gek: Gradient-Enhanced Kriging

Add a Vector Field to a Plot

Description

Draw a vector field to an existing plot.

Usage

vectorfield(x, gradient, scale = 1, max.len = 0.1, min.len = 0.001, ...)

Arguments

x	a matrix with 2 columns containing the coordinates.
gradient	a matrix with 2 columns columns containing the corresponding gradients at the locations in x.
scale	a scaling factor for the arrows to be drawn.
max.len	the maximum length of the edges of the arrow head.
min.len	the minimum length of the edges of the arrow head.
...	further graphical parameters to be passed to arrows.

Author(s)

Carmen van Meegen

See Also

arrows for drawing arrows between pairs of points.

Examples

x <- seq(-2, 2, 0.2)
n <- length(x)
X <- expand.grid(X = x, Y= x)

f <- function(x,y) x * exp(-x^2-y^2)
df <- deriv(~ x * exp(-x^2-y^2), c("x", "y"), function(x, y){})
res <- df(X[, 1], X[,2])
grad <- attr(res, "gradient")

contour(x, x, matrix(res, n, n), asp = 1)
vectorfield(X, grad)
contour(x, x, matrix(res, n, n), asp = 1)
vectorfield(X, grad, col = 4, code = 1, scale = 2)
contour(x, x, matrix(res, n, n), asp = 1)
vectorfield(X, grad, col = 4, lwd = 2, scale = 2)
contour(x, x, matrix(res, n, n), asp = 1)
vectorfield(X, grad, col = 1, angle = 20, scale = 2)
contour(x, x, matrix(res, n, n), asp = 1)
vectorfield(X, grad, col = 4, angle = 20, length = 0.1)
contour(x, x, matrix(res, n, n), asp = 1)
vectorfield(X, grad, col = 4, angle = 20, length = 0.1, scale = 2)
contour(x, x, matrix(res, n, n), asp = 1)
vectorfield(X, grad, col = 3, min.len = 0.1, max.len = 0.15, scale = 2)

gek documentation built on Jan. 31, 2026, 1:07 a.m.