How can I use summation and product, simultaneously???

Firstable Thank you for your kind.

I'm not good at MATLAB, so I always get information from this web-site.

I want to use summation(symsum) and product(symprod), simultaneously??

The equation is below.

plz help me...

Answer 1

[KSSV]

Something like this:

m = 2 ;  % i 
n = 3 ;  % j 

C = rand(m,1) ; 
k = rand(m,n) ;
M = rand(m,n) ; 

iwant = zeros(m,1) ; 

for i = 1:m
    p = 1 ; 
    for j = 1:n
        p = p*(1-k(i,j))^M(i,j) ;
    end
    iwant(i) = C(i)*p ; 
end

Please cross check the code, I gave it quickly.

[연승 김]

it works!! thank you.

But, is there any method to use 'symsum' and 'symprod'??

[Steven Lord]

symsum and symprod are not the right tools for this job. You cannot use them to evaluate expressions where the symbolic variables are used as indices into an array.

syms k
symsum(2.^k, k, 1, 10) % works

ans = 

2046

x = 1:10;
symsum(x(k), k, 1, 10) % does not work

Error using sym/subsindex (line 864)
Invalid indexing or function definition. Indexing must follow MATLAB indexing. Function arguments must be symbolic variables, and function body must be sym expression.

[연승 김]

Okay I understand!

THANK YOU for your kind!! Be happy^^