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 calling sequence 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 progession 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 xand y.

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

Examples

t = linspace(0,10*%pi,500);
clf();set(gca(),"isoview","on"); //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)])

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

• comet3d
• paramfplot2d

Authors

• Serge Steer

History

• First version April 2011, for Scilab-5.3.2