direction field of a 2D first order ODE
fchamp(f, t, xr, yr, [arfact, rect, strf]) fchamp(f, t, xr, yr, <opt_args>)
an external (function or character string) or a list which describes the ODE.
It can be a function name
fis supposed to be a function of type
y=f(t, xy, [p1, ..., pn]).
freturns a column vector of size 2,
y, which gives the value of the direction field
xy=[x,y]and at time
It can also be an object of type list,
list(f,P1, ..., Pn)where
fis a function of type
y=f(t, xy, p1, ..., pn)and
Pigives the value of the parameter
the selected time.
- xr, yr
two row vectors of size
n2which define the grid on which the direction field is computed.
This represents a sequence of statements
key1=value1, key2=value2,... where
key2,... can be one of the following:
- arfact, rect, strf
Optional arguments, see
fchamp is used to draw the direction field of a
2D first order ODE defined by the external function
Note that if the ODE is autonomous, argument
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)
- champ — plots as arrows a field of 2D vectors
- champ_properties — description of the 2D vector field entity properties
- xarrows — draw a set of arrows in 2D or in 3D.
- Arrowed polyline — description of the Polyline entity properties
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