Index exceeds the number of elements (1) HELP

it gives me an error with the x1 calculation

% Ask for inputs
y1 = input('Please input y1:');
t = input('Please input T:');

% Calculations

y2 = 1-y1;
p1 = exp(16.59158-(3643.31/(t-33.424)));
p2 = exp(14.25326-(2665.54/(t-53.424)));
a = 2.771-(0.00523*t);

% Initialize
c1(1) = 1;
c2(1) = 1;


% Initial P calculation
p(1) = 1./((y1/(c1(1)*p1)+(y2/(c2(1)*p2))));

% loop

for i = 2:8
    
    % update calculations
    
    x1(i) = (y1.*p(i-1))./(c1(i).*p1);
    x2(i) = (y2.*p(i-1))./(c2(i).*p2);
    c2(i) = exp(a.*(x1(i).^2));
    c1(i) = exp(a.*(x2(i).^2));
    p(i)=  1./((y1./(c1(i).*p1)+(y2./(c2(i).*p2))));

 
end

[tejas alva]

x1(i) = (y1.*p(i-1))./(c1(i).*p1);

c1(i) in the for loop would start with c1(2) which has not been initialized. I think if you sort that for all variables, including c2, it should not throw you any error.

Answer 1

[Anant Upadhyay]

Hi Cansu,

According to my understanding, you are facing error while calculating x1 because, in the expression

>> x1(i) = (y1.*p(i-1))./(c1(i).*p1);

“x1(i)” depends upon the value of “c1(i)” which is not being initialized/pre-calculated. Similar pattern is repeated for “x2(i)” also.

It may be a case, that for updating “x1(i)” you require “c(i-1)” and not “c(i)”.