MATLAB: Must return a column vector

column vector

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]);

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

Notice the ; instead of ,

You have the indices reversed.

Try this:

function dydt = Phase_1(t, y)
dydt(1,1) = y(3);
dydt(2,1) = y(4);
dydt(3,1) = 2*t;
dydt(4,1) = 1.5*t;
dydt(5,1) = t^(1/9);
dydt(6,1) = t^(1/6);
end

This works for me (in R2015a):

govequ = @(t,y) -t.^2-4*y;
[ts,ys] = ode45(govequ, [0,10], 1);
figure(1)
plot(ts, ys)
grid