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Scilab Help >> Graphics > 2d_plot > champ1

champ1

2D vector field plot with colored arrows

Syntax

champ1(x, y, fx, fy, [arfact, rect, strf])

Arguments

x, y

two vectors which define the grid.

fx

a matrix which describes the x component of the vector field. fx(i,j) is the x component of the vector field at point (x(i),y(j)).

fy

a matrix which describes the y component of the vector field. fy(i,j) is the y component of the vector field at point (x(i),y(j)).

arfact

an optional argument of type real which gives a scale factor for the display of the arrow heads on the plot (default value is 1.0).

rect

a vector rect = [xmin, ymin, xmax, ymax] which gives the boundaries of the graphics frame to use.

frameflag

controls the computation of the actual coordinate ranges from the minimal requested values. The associated value should be an integer ranging from 0 to 8.

axesflag

specifies how the axes are drawn. The associated value should be an integer ranging from 0 to 5.

strf

a string of length 3 "xyz" which has the same meaning as the strf parameter of plot2d. The first character x has no effect with champ1.

Description

champ1 draws a 2D vector field with colored arrows. The color of the arrows depends on the intensity of the field.

If you want arrows proportional to the intensity of the field, use champ.

Enter the command champ1() to see a demo.

Be cautioned about the fact that using meshgrid function before using champ1 requires adjustment. For more details, see the last example below.

Examples

champ1(-5:5,-5:5,rand(11,11),rand(11,11),rect=[-10,-10,10,10],arfact=2) // using meshgrid to get fx and fy
clf()
x = linspace(-1,1,30);
y = linspace(-1,1,30);
[X,Y] = meshgrid(x,y);
fy = 2.*Y;
fx = 2.*X;
champ1(x,y,fx',fy'); //here we have transposed fx and fy • champ — 2D vector field plot
• fchamp — direction field of a 2D first order ODE
• plot2d — 2D plot