Not able to figure out the way to deal with large vectors

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Hi ,
I was doing problem and faced a issue how to deal with large vectors .
I have a function
x(n) = e0.1n [u (n + 5) – u (n − 10)]
and want to fetch the even and odd components of it to perform some operations over them .The issue i am computing them by iterating through the since to get access of the values and checking if it is odd or even and perform operation right away there.But it might be too silly to use when 'n' value goes very high .
can anyone suggest any good way for that ? Here is the Pseduo code
for loop
%%cheking the conditions if the current x(n)
%%value is odd or even and performing operations there only .
%%plot the parts

Accepted Answer

Harsh Kumar
Harsh Kumar on 20 Jul 2023
Edited: Harsh Kumar on 20 Jul 2023
Hi Bhaskar ,
I understand that you are looking to compute the odd and even parts of a function optimistically in MATLAB .
To achieve this, you can use the vector definition of function and use the theoretical definition of odd/even function to compute them optimistically .
Odd= (func(x)-func(-x))/2
Even= (func(x)+func(-x))/2
Refer to the below code snippet for better understanding .
func1=exp(0.1*n).*((n>=-5)-(n>=10)); % orginal function
func2=exp(-1*0.1*n).*((n<=5)-(n<=-10)); %conjugate function
odd=(func1-func2)/2; %odd function calculated using given formula
even=(func1+func2)/2; %even function calculated using given formula
Refer to the documentation for more details on vector operations :

More Answers (2)

KSSV on 20 Jul 2023
c1 = 0 ; c2 = 0 ;
E = zeros([],1) ;
O = zeros([],1) ;
for i = 1:length(n)
%% Get your x(n)
if mod(x(n))
c1 = c1+1 ;
% Odd do your calculations
% save the value
O(c1)=val ;
c2 = c2+1 ;
% even do your calculation
% save the value
E(c2) = val ;
%%plot the parts
hold on
Alternatively, you can calculate x in the loop and later find it is even or odd using mod. This would be vectorised.

Walter Roberson
Walter Roberson on 20 Jul 2023
mask = mod(x,2) == 1;
Now do the "odd" operations on x(mask) and do the "even" operations on x(~mask).


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