comet

Parameters

x

a real vector or matrix. If omitted, it is assumed to be the vector 1:ny where ny is the number of curve points (see below).

y

a real vector or matrix of length.

p

a real scalar in the interval[0 1[. Default value is 0.1.

fun

a scilab function with syntax y=fun(x). fun can also be a polynomial or a rational fraction.

c

a vector of ny color index.

Description

If (x,y) are two vectors with the same number of elements, this function draws a 2D comet animated plot showing the progression of the curve (x(1:k),y(1:k)) for k varying from 1 to size(x,'*').

The plot is made of three parts:

a head

mark that shows the current (x(i),y(i)) position.

a body

that shows the trailing curve that follows the head: the (x(i-k:i),y(i-k:i)) part of the curve.

a tail

that shows the (x(1:i-k),y(1:i-k)) part of the curve.

comet(x,fun,...) is equivalent to comet(x,feval(x,fun),...).

comet(...,p) can be used to set the relative length of the body. k is defined as k = round(p*ny).

If y is a matrix then animated curves are drawn for each pair (x,y(:,l)). In this case ny is the number of rows of y.

If x and y are matrices with identical sizes then animated curves are drawn for each pair (x(:,l),y(:,l)). In this case ny is the number of rows of x and y.

comet(...,"colors",c) can be used to set the colors of each curves.

Examples

t = linspace(0,10*%pi,500);
clf();
isoview; //set isoview axes
comet(t.*sin(t), t.*cos(t))

t = linspace(0,10*%pi,500)';
clf();
comet(t.*sin(t), [t.*sin(2*t) t.*sin(3*t)])

t = linspace(0,10*%pi,500)';
clf();comet(t.*sin(t),[t.*sin(2*t) t.*sin(3*t)],"colors",[3 5])

function y=traj(x)
  y=1.5*sin(x^2)
endfunction
clf();
comet(linspace(0,5,500),traj)

clf();
comet(linspace(-2,4,500), (%s-3)/(%s^3+2*%s^2+1))

See also

• color — returns the color id of a color
• comet3d — 3D comet animated plot.
• paramfplot2d — animated plot of a 2D parametrized curve.

History