Error in for loop calculation

Hi, I am getting 0 as answer though the answers cannot be zero. If some one can guide

temperature = 212 ; % temperature in deg F
oilapi = 41 ; % oil API
gamma = (0.00091 * temperature) - (0.0125*oilapi);
gasg = 0.65 ;
U(100)= 100;
for P = 101:2000
U(P) = gasg * U(P-1);                   %/ (18 * (10 ^ (gamma)))^1.205);
end
U

Answer 1

[Stephen23]

You are confusing data with indices. Do not use data as indices.

temperature = 212 ; % temperature in deg F
oilapi = 41 ; % oil API
gamma = (0.00091 * temperature) - (0.0125*oilapi);
gasg = 0.65 ;
P = 100:2000; % data!
U = P;        % data!
for k = 2:numel(U) % indices!
    U(k) = gasg * U(k-1);                   %/ (18 * (10 ^ (gamma)))^1.205);
end
U

U = 1×1901

100.0000 65.0000 42.2500 27.4625 17.8506 11.6029 7.5419 4.9022 3.1864 2.0712 1.3463 0.8751 0.5688 0.3697 0.2403 0.1562 0.1015 0.0660 0.0429 0.0279 0.0181 0.0118 0.0077 0.0050 0.0032 0.0021 0.0014 0.0009 0.0006 0.0004