how to overcome undefined function sum.

 throughput_E =@(t)Bmax*log2(1+p_fix(t)*gamma(t)/sum(p_fix(q,1,t-1).*gamma(t)));              
 overall_throughput_E = sum(sum(throughput_E));

If i run the code i am getting Undefined function 'sum' for input arguments of type 'function_handle'.

Error in overall_throughput_E = sum(sum(throughput_E));

[KSSV]

define p_fix as a anonymous function and try.

[Prabha Kumaresan]

throughput_E = @(t)Bmax*log2(1+p_fix(t)*gamma(t)/symsum(p_fix(q,1,t-1).*gamma(t)))
            overall_throughput_E = sum(sum(throughput_E));

after using anonymous function i am stiil getting

Undefined function 'sum' for input arguments of type 'function_handle'.

Error in overall_throughput_E =
            sum(sum(throughput_E));

[KSSV]

:( what is p_fix.....show us this function.

[Prabha Kumaresan]

p_fix is the fixed power which was given by 0.01 .

Answer 1

[Matt J]

You need to give some sort of input to throughput_E in this line

sum(sum( throughput_E( t_input) ));

[John D'Errico]

To amplify on what Matt said, and explain why there was a problem...

throughput_E is a function handle. It seems like it makes sense that you can sum the function, simply by putting it inside sum. But MATLAB does not understand your goal here. MATLAB is a very literal tool. The function sum looks at what you passed in. Sum recognizes only numeric inputs as candidates to be summable. It looks at throughput_E, and sees that it is NOT a number or vector or array of numbers. So sum just gives up and throws an error.

If you change things, so that throughput_E has an input as did Matt, then the result is now numeric. MATLAB evaluates the function at t_input, then passes the result to sum. All is good now.

Sometimes you really don't immediately have the input to throughput_E at the moment, but you want to define a new function that will take any input and sum the result, after going through throughput_E? Just create a NEW function, as I do here:

sum_of_throughput_E = @(inp) sum(sum(throughput_E(inp)));

So now you can use this new function as the summed result.

[Prabha Kumaresan]

i am getting the error

 Undefined function or variable 't_input'

if i use sum(sum( throughput_E( t_input) ));

and if i use

sum_of_throughput_E = @(inp) sum(sum(throughput_E(inp)));

in the below coding

throughput_E = @(t)Bmax*log2(1+p_fix(t)*gamma(t)/symsum(p_fix(q,1,t-1).*gamma(t)))
% overall_throughput_E = sum(sum(throughput_E(t_input)));
overall_throughput_E = sum(sum(throughput_E));
 sum_of_throughput_E = @(inp) sum(sum(throughput_E(inp)));
%             
            output_E(t,r)=overall_throughput_E;
            output_E_it(t,r,it)=output_E(t,r);

i am getting Undefined function 'sum' for input arguments of type 'function_handle'.

Error in 
overall_throughput_E = sum(sum(throughput_E));

Please help me to solve it.

[Matt J]

Undefined function or variable 't_input'

You must define t_input! What data are you trying to run throughput_E on?