must return a column vector

Question

Taorui Wang 2019-5-3

评论： Taorui Wang 2019-5-3

I was drawing a vector field using phaplane, but I cannot draw any specific solution curve

>> g = @(t,Y) [Y(2), -Y(1)]
>> phaseplane(g, [-10,10], [-10,10], 25)
>> hold on
>> drawphase(g, 50, 3, 4)

Error using odearguments (line 93)

@(T,Y)[Y(2),-Y(1)] must return a column vector.

Error in ode45 (line 115)

odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in drawphase (line 20)

[ts,ys] = ode45(g,[0,tmax],[y1start;y2start]);

Answer 1

Walter Roberson 2019-5-3

g = @(t,Y) [Y(2); -Y(1)];

Notice the ; instead of ,

Taorui Wang 2019-5-3

Cannt believe i made such a silly mistake! Thank you for pointing that out and responding so quickly