direction field of a 2D first order ODE
fchamp(f, t, xr, yr, [arfact, rect, strf]) fchamp(f, t, xr, yr, <opt_args>) h = fchamp(...)
an external (function or character string) or a list which describes the ODE.
It can be a function name f,
where f is supposed to be
a function of type y=f(t, xy, [p1, ..., pn]).
f returns a column vector
of size 2, y, which gives
the value of the direction field f
at point xy=[x,y] and at
time t.
It can also be an object of type list,
list(f,P1, ..., Pn) where
f is a function of type
y=f(t, xy, p1, ..., pn)
and Pi gives the value of
the parameter pi.
the selected time.
two row vectors of size n1 and
n2 which define the grid on
which the direction field is computed.
This represents a sequence of statements
key1=value1, key2=value2,...
where key1, key2,...
can be one of the following: arfact,
rect, strf (see
below).
Optional arguments, see champ.
This optional output contains a handle to a Champ entity. Use h to modify its properties
For a list of properties, see champ_properties.
fchamp is used to draw the direction field of a
2D first order ODE defined by the external function
f.
 | Note that if the ODE is autonomous, argument
t is useless, but it must be given. |
Enter the command fchamp() to see a demo.
deff("[xdot] = derpol(t,x)",.. ["xd1 = x(2)";.. "xd2 = -x(1) + (1 - x(1)**2)*x(2)";.. "xdot = [ xd1 ; xd2 ]"]) xf= -1:0.1:1; yf= -1:0.1:1; fchamp(derpol,0,xf,yf) |  |  |
deff("[xdot] = derpol(t,x)",.. ["xd1 = x(2)";.. "xd2 = -x(1) + (1 - x(1)**2)*x(2)";.. "xdot = [ xd1 ; xd2 ]"]) xf= -1:0.1:1; yf= -1:0.1:1; clf() fchamp(derpol,0,xf,yf,1,[-2,-2,2,2],"011") | | |
| Version | Description |
| 2025.0.0 | Function returns the created handle(s). |