fchamp(2)

NAME
fchamp - draw a 2d vector field

CALLING SEQUENCE
fchamp(f,t,xr,yr,[arfact,flag])

PARAMETERS

f   : a function which describes the vector field.

    -   It can be a function name f, where f is supposed to be a function of type [y]=f(t,x,[u]) ( f returns a column vector of dimension 2, y, which gives the value of the vector field f at point x and time t.

    -   It can also be an object of type list, list(f1,u1) where f1 is a function (f [y]=f1(t,x,u) ) and u1 gives the value of the parameter u.

t   : The selected time.

xr,yr
    : two vectors of size (1,n1) (1,n2) which specifies the grid on which the vector field is to be computed.

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)

flag
    : string of length 1

    "0" : No axis (default value)

    "1" : axis using the value of rect

    "2" : axis and rectangle using previous call.

DESCRIPTION
the fchamp is used to draw a two dimensional vector field described by a a Scilab external.

EXAMPLE
enter the command champ() to see a demo

Another example :
 deff('[xdot] = derpol(t,x)',['xd1 = x(2)';
           "xd2 = -x(1) + (1 - x(1)**2)*x(2)";
           "xdot = [ xd1 ; xd2 ]"]);
 fchamp(derpol,0,-1:0.1:1,-1:0.1:1);

AUTHOR
J.Ph.C.