AVOID FOR LOOP for changing size vector

Question

gabriele fadanelli 2020-3-27

回答： Abhisek Pradhan 2020-3-30

I need to solve this problem without a for loop:

B= (1:20)   
A = [];                     
A(1) = 1/(1+B(1));      
for k = 2:length(B)
    A(k,1) = (1-B(k)*sum(A))/(1+B(k));    
end

i.e. I need to know if it is possible to get information from previous calculation to create a vector, but without a for loop. Thanks.

Adam 2020-3-27

Can't think if there is a way to avoid a for loop for that, but the vector size certainly does not need to change. You can presize A as

A = zeros( size( B ) );

编辑：gabriele fadanelli 2020-3-27

Thank you! Actually I was trying to change the for loop at first.

Answer 1

Abhisek Pradhan 2020-3-30

I could understand you want to avoid use of loop. This can be done using vectorization.

Refer the following link which has few examples on how to do vectorization.