Error: Subscript indices must either be real positive integers or logicals. Please help me. My code

N3 = @(z)(exp(-(m+n)*z).*(-exp(2*l*n+(m+n)*z).*lamda.*n^2.*(3*m-(1+l*m)*n+l*lamda*n^4)+exp(n*(2*l+z)).*lamda^2.*n^6.*(l-z)+exp(l*(m+n)+m*z).*m^2.*(l*n*(l-z)-z)+exp(l*m+(m+n)*z).*m^2.*z-exp(l*n+(m+n)*z).*lamda.*n^3.*(-2*m+n).*z+exp(l*m+2*l*n+n*z).*lamda.*n^2.*(3*m-n-m*n*z+lamda*n^4*z)-exp(2*l*n+m*z).*lamda.*n^2.*(n+m*(-3+l*n-n*z))-exp(l*(m+n)+n*z).*lamda.*n^2.*(-n*(1+l*n)+m*(3+l*n*(3+l*n)-n*(1+l*n)*z))+exp(l*m+2*l*n+m*z).*(m^2*z+lamda*n^2*(n-m*(3+n*z)))-exp((m+n)*(l+z)).*(l^2*m*n*(m-lamda*n^3)+m^2*z+lamda*n^2*(-3*m+n+(2*m-n)*n*z)+l*n*(-m^2*z+lamda*n^2*(n+m(-3+n*z))))))/((exp(l*m).*m^2-exp(l*n).*lamda.*n^3.*(-2*m+n)+exp(l*(m+2*n)).*(m^2+2*lamda*m*n^3-lamda*n^4)+exp(2*l*n).*lamda.*n^3.*(n+m*(-2+l*n))-exp(l*(m+n)).*(-lamda*n^4+lamda*m*n^3*(2+l*n)+m^2*(2+l^2*n^2))));

Answer 1

[John D'Errico]

Hint: Never define a variable named exp. If you do, you will get that error.

Try this:

which exp -all

If that is not the problem, then look carefully at your code. Is there ANY place where you have a variable with NO operator between the variable and an open parens? Consider this line from your code:

n)*n*z)+l*n*(-m^2*z+lamda*n^2*(n+m(-3+n*z))))))/((exp(l*m).*m^2-exp(l*n).*lamda.*n^3.*

What might you have intended by the fragment m(-3+n*z)?

Is m a function? Is m a variable to be indexed by the expression -3+n*z? Or did you really intend there to be an operator between the m and the ( ?

When you get an error like this, look carefully at your code. If I could find it easily enough, surely you could have found it in much less time than it took me to answer this question.

There may be other errors. Check your code.

[thanh pham]

Sorry. I dont understand. Shall you repair my code. Please. I readly want it. Exp is logarit(e)

[John D'Errico]

You did not read the rest of my answer. How should MATLAB evaluate the expression:

m(-3+n*z)

when you answer that question, then you will know how to repair your code. Until then, I cannot know what you intended there.

[thanh pham]

thank you very much. i done it