How to solve the error "[t, z]= ode45(@observer, t_temp,z0)" in line 23.

function will
    clc
    global E A B C N P L M x0 tspan u
    E=[0.5 -2.5 0;3 -3 4;2 -1 3];
    A=[-1 4.5 -0.5;-7 7 -8;-5 3 -6];
    B=[1 0 1;0 1 1;1 0 -1];
    C=[1 0 1];

  N=[-0.75 -1 0.25;0 -2 0;0.25 1 -0.75];
    L = [51.3257 11.2723;41.5581 7.8378;-24.3673 -6.2663];
    M = [-0.4488 2.4167;-0.0898 0.4833;0.2693 -1.4500];
    R = [0.3565 0.6582;0.1578 -0.2295;-0.3565 -0.6582]
    B1= [-0.7306 -0.8299 -0.5319;0.4742 0.0304 1.3620]
    P = R*B1
    x0 = [1 0 -1];
    tspan = 0:.1:20;
    [x,y]=solbasic;
    function dzdt = observer(t,z)
    dzdt=N*z+L*[(y(i,:)+y(i+1,:))/2]'+P*u;
    end
    z0=[10 11 6];
    for i = 1:length(y)-1;
    t_temp =((i-1)/10):.05:(i/10);
    [t,z]=ode45(@observer,t_temp,z0);
    end
    z1;
    x;
   x_cap=z+y*M';
    e=x-x_cap;
end
 function [x,y] = solbasic()
 %y is the output which we will get after finding value of x
 global E tspan x0 C
    opt = odeset('RelTol',1e-6,'Mass',E);
    [~, x] = ode15s(@basic, tspan, x0, opt)
    y = x*C';
end
function dxdt = basic(t,x)
global A B u
 u=[exp(-t)*sin(t);0.2*sin(2*t);0.2*sin(3*t)];
 dxdt=A*x+B*u;
 end
 
My errors are-
Error using odearguments (line 93)
WILL/OBSERVER must return a column vector.

Error in ode45 (line 115)
  odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
  Error in will (line 23)
    [t,z]=ode45(@observer,t_temp,z0);
 

Answer 1

[Mischa Kim]

dzdt seems to be a (3x2 ?) matrix. It needs to be a 3x1 vector to be consistent with the initial conditions, z0, which is also a 3-component vector.

function dzdt = observer(t,z)
  dzdt = N*z + L*[(y(i,:)+y(i+1,:))/2]' + P*u;
end

[Meenakshi Tripathi]

it worked.

Thank you so much sir for your quick reply.