Getting NaN for the mean of a vector, is this normal?

Hi there,

So I wrote a code here an when I try to calc the mean I get a NaN result for the final mean. This is due inaround 5 hours and I have no idea what to do. Any ideas?

%% Get user input

Prototype_id = input('Please Enter the prototype ids in vector form: ');

Time_intial = input('Please input the activation times in vector form: ');

Time_Final = input('Please inputthe time of decay in vector form: ');

% Calculate the mean time for activation

Mean = mean(Time_intial);

% Calculate the mean time for decay

Mean_f = mean(Time_Final);

%% Display the result

disp(['The number of prototypes is: ', num2str(Prototype_id)]);

disp(['The average amount of time for activation is: ', num2str(Mean)]);

disp(['The average amount of time for decay is: ', num2str(Mean_f)]);

[Ameer Hamza]

What are the inputs Time_intial and Time_Final?

[Loic Roy-Seger]

Please Enter the prototype ids in vector form: [3:8:14:17:21:22:25:32:34:40:46:43:48:49]

Please input the activation times in vector form: 0:12:6:17:32:14:35:22:10:18:29:23:4:15

Please inputthe time of decay in vector form: 130:115:158:180:250:292:117:217:231:172:123:182:218:200

[Loic Roy-Seger]

At least, that's what I plugged in

Answer 1

[Ameer Hamza]

I think you misunderstand the colon operator. Read about it here: https://www.mathworks.com/help/matlab/ref/colon.html. You should input these values like this

prototype ids

[3, 8, 14, 17, 21, 22, 25, 32, 34, 40, 46, 43, 48, 49]

activation times

[0, 12, 6, 17, 32, 14, 35, 22, 10, 18, 29, 23, 4, 15]

time of decay

[130, 115, 158, 180, 250, 292, 117, 217, 231, 172, 123, 182, 218, 200]

[Stephen23]

+1 Even better would be to always use comma delimiter, as the space is a common cause of bugs:

https://www.mathworks.com/matlabcentral/answers/320231-either-i-or-matlab-is-going-crazy-with-vertcat-using-brackets

https://www.mathworks.com/matlabcentral/answers/460861-error-when-calling-a-function-dimensions-of-arrays-being-concatenated-are-not-consistent

https://www.mathworks.com/matlabcentral/answers/374549-dimensions-of-matrices-being-concatenated-are-not-consistent

https://itectec.com/matlab/matlab-error-when-calling-a-function-dimensions-of-arrays-being-concatenated-are-not-consistent/

[Ameer Hamza]

Yes, it might cause confusion and bug in some cases. I have updated the answer to use commas as the separator.

Answer 2

[Sudhakar Shinde]

NaN returns the scalar representation of "not a number". Operations return NaN when they have undefined numeric results, such as 0/0 or 0*Inf.

[Loic Roy-Seger]

See I know that and that's the reason why I'm confused because it's a vector with normal numbers that should work

[Sudhakar Shinde]

time of decay in vector form gives an empty vector and hence mean is NaN.