MATLAB: Errors when using the function ODE 45

differential equationserrorMATLABode45

Hello! Please help me when using ODE 45! I receive errors:
1) Not enough input arguments. Error in peFun (line 5) eta=ALPHA(1);
2) Error in odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
3) Undefined function or variable 'vPUR'
function fval=peFun(t,ALPHA)
tspan=[0 1];
% Get variables
eta=ALPHA(1);
r=ALPHA(2);
beta=ALPHA(3);
alpha=ALPHA(4);
xP=ALPHA(5);
yP=ALPHA(6);
xE=ALPHA(7);
yE=ALPHA(8);
% Constants
vER=3;
vPUR=5;
a=1;
% Describing dALPHA/dt
fval=zeros(8,1);
fval(1,1)=(-vPUR*SIN(beta)+vER*SIN(alpha))/r;
fval(2,1)=vER*COS(alpha)-vPUR*COS(beta);
fval(3,1)=(a/r)*(vER*SIN(alpha)-vPUR*SIN(beta));
fval(4,1)=(-vER*SIN(alpha)+vPER*SIN(beta))/r;
fval(5,1)=vPUR*COS(eta+beta);
fval(6,1)=vPUR*SIN(eta+beta);
fval(7,1)=vER*COS(eta+alpha);
fval(8,1)=vER*SIN(eta+alpha);
% To run P-E system
%%Initialization
eta0=pi/4;
r0=sqrt(2);
beta0=0;
alpha0=pi/4;
xP0=0;
yP0=0;
xE0=1;
yE0=1;
ALPHA0=[eta0;r0;beta0;alpha0;xP0;yP0;xE0;yE0];
%Solve using ODE45
[tSol,ALPHASol]=ode45(@peFun,tspan,ALPHA0);
%Plot the results
plot(tSol,ALPHASol);
Thank you!

Best Answer

tspan=[0 1];
% To run P-E system
%%Initialization
eta0=pi/4;
r0=sqrt(2);
beta0=0;
alpha0=pi/4;
xP0=0;
yP0=0;
xE0=1;
yE0=1;
ALPHA0=[eta0;r0;beta0;alpha0;xP0;yP0;xE0;yE0];
[tSol,ALPHASol]=ode45(@peFun,tspan,ALPHA0);      %function calling before function definition
plot(tSol,ALPHASol);
function fval=peFun(t,ALPHA)
% Get variables
eta=ALPHA(1);
r=ALPHA(2);
beta=ALPHA(3);
alpha=ALPHA(4);
xP=ALPHA(5);
yP=ALPHA(6);
xE=ALPHA(7);
yE=ALPHA(8);
% Constants
vER=3;
vPUR=5;
a=1;
% Describing dALPHA/dt
fval=zeros(8,1);
fval(1,1)=(-vPUR*sin(beta)+vER*sin(alpha))/r;
fval(2,1)=vER*cos(alpha)-vPUR*cos(beta);
fval(3,1)=(a/r)*(vER*sin(alpha)-vPUR*sin(beta));
fval(4,1)=(-vER*sin(alpha)+vER*sin(beta))/r;
fval(5,1)=vPUR*cos(eta+beta);
fval(6,1)=vPUR*sin(eta+beta);
fval(7,1)=vER*cos(eta+alpha);
fval(8,1)=vER*sin(eta+alpha);
end
Related Question