# comet

2D comet animated plot

### Syntax

comet(y) comet(x, y) comet(x, y, Lf) comet(x, fun) comet(x, fun, Lf) comet(..., "colors",c)

### Parameters

- x
- a real vector or matrix. If omitted, it is assumed to be the vector
`1:np`

where`np`

is the total number of curve points (see below). As a matrix, each column defines the abscissae of the trace of a separate comet. - y
- a real vector or matrix. As a matrix, each column defines the ordinates
of the trace of a separate comet.
`nc=size(y,"c")`

is the number of comets simultaneously drawn. - Lf
- a real scalar in the interval
`[0,1[`

. Default value is 0.1: It defines the Leading fraction of the comet's trace. The`k=Lf*np`

most recent points are plotted in thicker line. - fun
- a scilab function with syntax
`y = fun(x)`

.`fun`

can also be a polynomial or a rational fraction. - c
`nc`

colors of the`nc`

comets traces. They may be specified as a vector of`nc`

color indices or color names or "#RRGGBB" hexadecimal color codes. Or by a matrix (ncx3) of`[r,g,b]`

vectors of Red-Green-Blue intensities in the [0,1] interval.

### Description

If `(x,y)`

are two vectors, this function draws a 2D comet animated
plot showing the progression of the curve `(x(1:m),y(1:m))`

for
`m`

varying from `1`

to
`np=length(x)`

.

The plot is made of three parts:

a head |
mark that shows the current `(x(i),y(i))` position. |

a body |
consisting in the `k=round(Lf*np)` most recent points
of the trajectory, displayed as a thicker part of the trace. |

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),...)`

.

If `x`

and `y`

are matrices with identical sizes,
then animated curves are drawn for each pair `(x(:,j),y(:,j))`

.
In this case `np`

is the number of rows of
`x`

and `y`

.

`comet(...,"colors",c)`

can be used to set the colors of each
trajectory.

### Examples

// One comet in spiral: t = linspace(0, 10*%pi, 500); clf, isoview comet(t.*sin(t), t.*cos(t), "colors", "orange")

// Two simultaneous comets with default colors: t = linspace(0, 10*%pi, 500)'; clf comet(t.*sin(t), [t.*sin(2*t) t.*sin(3*t)])

### See also

- comet3d — 3D comet animated plot
- paramfplot2d — animated plot of a 2D parametrized curve.
- realtime — sets the time unit
- colors names — list of named colors

### History

Version | Description |

5.3.2 | Function comet() introduced. |

6.1.0 | Colors can now be specified also by their name, or by their "#RRGGBB" hexadecimal code, or by their [r g b] Red-Green-Blue intensities. |

Report an issue | ||

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