I am getting error like invalid expression

function Le=lyapunovk(n,rhs_ext_fcn,tstart,stept,tend,ystart,R);

n1=n; n2=n1*(n1+1);

% Number of steps

nit = round((tend-tstart)/stept);

% Memory allocation

y=zeros(n2,1); cum=zeros(n1,1); y0=y;

gsc=cum; znorm=cum;

% Initial values

y(1:n)=ystart(:);

for i=1:n1

y((n1+1)*i)=1.0; end;

t=tstart;

% Main loop

for ITERLYAP=1:nit

% Solutuion of extended ODE system

[T,Y] = ode15s(rhs_ext_fcn,[t t+stept],y,R);

Y=transpose(Y);

t=t+stept;

y=Y(size(Y,1),:);

for i=1:n1

for j=1:n1

y0(n1*i+j)=y(n1*j+i); end;

end;

%

% construct new orthonormal basis by gram-schmidt

%

znorm(1)=0.0;

for j=1:n1

znorm(1)=znorm(1)+y0(n1*j+1)^2; end;

znorm(1)=sqrt(znorm(1));

for j=1:n1

y0(n1*j+1)=y0(n1*j+1)/znorm(1); end;

for j=2:n1

for k=1:(j-1)

gsc(k)=0.0;

for l=1:n1

gsc(k)=gsc(k)+y0(n1*l+j)*y0(n1*l+k); end;

end;

for k=1:n1

for l=1:(j-1)

y0(n1*k+j)=y0(n1*k+j)-gsc(l)*y0(n1*k+l);

end;

end;

znorm(j)=0.0;

for k=1:n1

znorm(j)=znorm(j)+y0(n1*k+j)^2; end;

znorm(j)=sqrt(znorm(j));

for k=1:n1

y0(n1*k+j)=y0(n1*k+j)/znorm(j); end;

end;

%

% update running vector magnitudes

%

for k=1:n1

cum(k)=cum(k)+log(znorm(k)); end;

%

% normalize exponent

%

for k=1:n1

lp(k)=cum(k)/(t-tstart);

end;

% Output modification

i=1;

while i<=n1

j=1;

while j<=n1;

y(n1*j+i)=y0(n1*i+j);

j=j+1;

end

i=i+1;

end;

y=transpose(y);

nit=nit+1;

end

function f=l_ext(t,x,R)

SIGMA = 10;

BETA = 8/3;

f=zeros(9,1);

X= [x(4) x(7) x(10);

x(5) x(8) x(11);

x(6) x(9) x(12)];

%Lorenz equation

f(1)=SIGMA*(x(2)-x(1));

f(2)=-x(1).*x(3)+R*x(1)-x(2);

f(3)=x(1).*x(2)-BETA*x(3);

%Linearized system

Jac=[-SIGMA, SIGMA, 0;

R-x(3), -1, -x(1);

X(2), x(1), -BETA];

%Variational equation

f(4:12)=Jac*X;

%Output data must be a column

function run_L_p(n,rhs_ext_fcn,0,0.5,200,[0 1 0],10,R_min,R_max,nk);

hold on;

rhs_ext_fcn=@l_ext

n=3;

nk=100;

R_min=10;

R_max=28;

R_step=(R_max-R_min)/nk

R=R_min;

while R<=R_max

lp=lyapunovk(3,@l_ext,0,0.5,200,[0 1 0],10,R);

R=R+R_step;

plot(R,lp);

end

I am gettion error:

Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses.

Answer 1

[Karim]

the error is located in syntax of the run_L_p function. You need to change the numeric values into variables

i.e. change

function run_L_p(n,rhs_ext_fcn,0,0.5,200,[0 1 0],10,R_min,R_max,nk)

into

function run_L_p(n,rhs_ext_fcn,var1,var2,var3,var4,var5,R_min,R_max,nk)

before call the function you need to define the extra variables as

var1 = 0;
var2 = 0.5;
var3 = 200;
var4 = [0 1 0];
var5 = 10;

or if they are fixed you can set them in the function itself.

[nune pratyusha]

Now it showing error like

>> run_L_p

rhs_ext_fcn =

function_handle with value:

@l_ext

R_step =

0.180000000000000

Error using lyapunovk

Too many input arguments.

Error in run_L_p1 (line 16)

lp=lyapunovk(3,@l_ext,0,0.5,200,[0 1 0],10,R);

>>

[Karim]

yes... it mentions Error using lyapunovk Too many input arguments which indicates that you call the function with to many inputs...

you call the function as

lyapunovk(3, @l_ext, 0, 0.5, 200, [0 1 0], 10, R)

which has 8 inputs.

However you have defined

lyapunovk(n, rhs_ext_fcn, tstart, stept, tend, ystart, R)

which expects 7 input variables... hence when you call the function it has too many inputs...

[nune pratyusha]

please suggest where i have to change the code to modify error

[Bruno Luong]

Sometime it's good to read what is displayed on your PC monitor:

"Error in run_L_p1 (line 16)

lp=lyapunovk(3,@l_ext,0,0.5,200,[0 1 0],10,R)"

[nune pratyusha]

yes after modification i changed functiom name as run_L_p1 and saved it as run_L_p1