Returning NaN after mean calculation?

Just wondring why my code is returning NaN when I use the mean fucntion? My numbers are not that big i have scaled back the number of runs from 1000 to 10 but still no change. I'm confused

clear all
close all
clc
% set up variables
no_of_calls = 60;
no_of_runs = 10;
CallTime = [];
CallLength =[];
n = ones(1,no_of_calls).*42;
E_1 = zeros(no_of_runs, no_of_calls);
call_timeDIST= makedist('Uniform');
call_lengthDIST = makedist('Poisson','lambda',3);
CallLength = zeros(no_of_runs,no_of_calls);
for i = 1:no_of_calls
    for j = 1:no_of_runs
        % Create distribution for calls in time
        CallTime(j) = random(call_timeDIST);
        % Create distribution for call length
        CallLength(j,i) = random(call_lengthDIST);
        % calculate A0
        A_0       = 600.*(CallLength./60);
        % calculate E_1 using Erlings-B Formula
        E_1(j,i) = part_2(A_0(j,i), n(i));
    end
    % Find Mean for number of iterations
    GOS = mean(E_1,2);
end

Unrecognized function or variable 'part_2'.

CT = sort(CallTime)';
plot(CT, GOS)

[Torsten]

We don't know what "part_2" does with A_0(j,i) and n(i).

[Cormac Carr]

function E_1 = part_2(A_0,n)

for i = 1:n

S(i) = (A_0^i)/factorial(i); %% Create vector of

% values to be summed

% to create denominator

dnom = cumsum(S); %% Create denominator

end

for n = 1:n

num1(n) = ((A_0^n)/factorial(n)); %% loop through values

% values of n for numerator

% createing vector of numerators

% for specified A0

end

for n = 1:n

E_1 = num1(n)./dnom(n); % Complete formula for answer

end

Answer 1

[David Hill]

function E_1 = part_2(A_0,n) 
n=1:n;
S = (A_0.^n)./factorial(n); 
dnom = cumsum(S);           
E_1 = S./dnom; 
end

[Cormac Carr]

Unable to perform assignment because the size of the left side is 1-by-1 and the

size of the right side is 1-by-42.

Error in EE4101_Cormac_Carr_Part2 (line 26)

E_1(j,i) = matlab(A_0(j,i), n(i));

[Cormac Carr]

Got it working thanks for your help