Code is not working, can someone help me?

So I have successfully written scripts for three different functions of 3 variables, Sum1(x,y,z) Sum2(x,y,z) and Sum3(x,y,z)

I have 2 other scripts for functions of just two of these variables: QuantumDimension(x,y) and Twist(x,y)

I'm trying to relate these functions as so:

function c = CJ(x,y,z)
c = (Twist(x,y)^(-2*z)/QuantumDimension(x,y))*(Sum1(x,y,z)+Sum2(x,y,z)-Sum3(x,y,z))
end

So Twist^(-2z) divided by the QuantumDimension, multipled by the sum of the three summations, (Sum1 + Sum2 + Sum3)

This is the output I get when I try to run the code:

Error in CJ (line 2)
c = (Twist(x,y)^(-2*z)/QuantumDimension(x,y))*(Sum1(x,y,z)+Sum2(x,y,z)-Sum3(x,y,z))

I do not see anything wrong with this line!! Insights appreciate, thanks for being patient.

[Rik]

What is the full error message (all the red text)? And how are you calling this function?

[Michael Vaughan]

Here is the error message:

__________________

Output argument "sum" (and maybe others) not assigned during call to "Sum1".

Error in CJ (line 2)

c = (Twist(x,y)^(-2*z)/QuantumDimension(x,y))*(Sum1(x,y,z)+Sum2(x,y,z)-Sum3(x,y,z))

__________________

i am calling the function by typing

CJ(3,2,2)

[Rik]

How did you define the Sum1 function?

Also note that using sum as a variable name is generally not a good idea, as it will then shadow the built-in function.

Also, is the minus sign intential before Sum3?

[Michael Vaughan]

Here is the code for Sum1

function sum = Sum1(x,y,z)

s = 0;

for i=0:min(x,y)

for k=0:x-i

s = s + (-1)^k * QuantumDimension(2*x-2*k-2*i, 2*y+k-2*i) * Twist(2*x-2*k-2*i, 2*y+k-2*i)^(z/2);

end

end

s

The minus sign is indeed intentional

Thanks for the tips! I really appreciate them

[Michael Vaughan]

I renamed sum to be s1 and now I get this error message:

Output argument "s1" (and maybe others) not assigned during call to "Sum1".

Error in CJ (line 2)

c = (Twist(x,y)^(-2*z)/QuantumDimension(x,y))*(Sum1(x,y,z)+Sum2(x,y,z)-Sum3(x,y,z))

Answer 1

[Rik]

This should fix it:

function s = Sum1(x,y,z)
s = 0;
for i=0:min(x,y)
  for k=0:x-i
      s = s + (-1)^k * QuantumDimension(2*x-2*k-2*i, 2*y+k-2*i) * Twist(2*x-2*k-2*i, 2*y+k-2*i)^(z/2);
  end
end
end

[Michael Vaughan]

Thanks man!! Much Appreciated!!

Another question: If I wanted to change CJ(x,y,z) to be a function of two variables whilst keeping z as an indeterminant, how would I have to alter my scripts?? I went through the scripts on Sum1, Sum2, Sum3, QuantumDimension and Twist and added syms z and turned them all into functions of two variables, but that didn't seem to work.

[Rik]

What do you mean by that? Do you want to provide z at a later time than x and y? Like a lambda? You can probably get most of the way there with an anonymous function.

Note that I didn't make an attempt to simplify or speed up your code, so the current shape of your functions may not allow you to do what you want.