ratio using for loops

https://www.mathworks.com/matlabcentral/answers/2035579-ratio-using-for-loops

I am still trying to solve it.

for s_ast=(0:1:T)
    ratio_1=(y_2^(s_ast+1)*(1-y_2^T)*(1-x_2)*epsilon_2^(s_ast+1))/(x_2^(s_ast+1)*(1-x_2^T)*(1-y_2));
    ratio_2=((1-y_1^(s_ast+1))*(1-x_1)*epsilon_1^(s_ast+1))/((1-y_1)*((1-x_1^(s_ast+1)+K^(1/gamma)*x_1^T*(1-x_1))));
    ratio_tax(s_ast+1)=ratio_1/ratio_2;
    if (ratio_tax>1)
        s_asterisk_tax=s_ast(end);
    else
        continue
    end
end 
disp(s_asterisk_tax);

As suggested, I simplified using geometric series and I excluded when x_1 and x_2, y_1 and y_2 are equal to 0.

However, I am getting s_asterisk_tax wrong.

What is wrong in my code?

Thank you,

Answer 1

[Walter Roberson]

if ratio_tax > 1
    s_asterisk_tax = s_ast;
    break;
end

And make sure you put in protection for the case that you get through all the s_ast values without the ratio ever being > 1.

[Raushan]

Unfortunately, it doesn't calculate correctly. What do you mean by put in protection.

for s_ast=(0:1:T)
    ratio_1=(y_2^(s_ast+1)*(1-y_2^T)*(1-x_2)*epsilon_2^(s_ast+1))/(x_2^(s_ast+1)*(1-x_2^T)*(1-y_2));
    ratio_2=((1-y_1^(s_ast+1))*(1-x_1)*epsilon_1^(s_ast+1))/((1-y_1)*((1-x_1^(s_ast+1)+K^(1/gamma)*x_1^T*(1-x_1))));
    ratio_tax(s_ast+1)=ratio_1/ratio_2;
    if (ratio_tax>1)
        s_asterisk_tax=s_ast(end);
    else
        continue
    end
end 
disp(s_asterisk_tax);

Am I indexing correctly?

In fact, ratio tax are

1.67222545714237 1.24503545388894 1.09297189680532 1.00973256667129 0.954062035513025 0.912212597405483 0.878295820907719 0.849370429500316 0.823804921876207 0.800622614482470 0.779203928807902

But I am always getting stopping time 3

[Walter Roberson]

ratio_satisfied = false;
for s_ast=(0:1:T)
    ratio_1=(y_2^(s_ast+1)*(1-y_2^T)*(1-x_2)*epsilon_2^(s_ast+1))/(x_2^(s_ast+1)*(1-x_2^T)*(1-y_2));
    ratio_2=((1-y_1^(s_ast+1))*(1-x_1)*epsilon_1^(s_ast+1))/((1-y_1)*((1-x_1^(s_ast+1)+K^(1/gamma)*x_1^T*(1-x_1))));
    ratio_tax(s_ast+1)=ratio_1/ratio_2;
    if (ratio_tax>1)
        s_asterisk_tax = s_ast;
        ratio_satisfied = true;
        break;
    end
end

if ratio_satisfied
    disp(s_asterisk_tax);
else
    disp('got through all iterations without the ratio being satisfied');
end

Note in particular that you were using s_ast(end) in your assignment to s_asterisk_tax . However, s_ast is the index variable in your for s_ast and as such it is assigned one value at a time. At any time within the for loop, s_ast is a scalar, so it does not make any sense to index s_ast(end) . It is not "wrong" to do so, but it indicates that you are confused about what you are doing, and it confuses people who read the code, so you should avoid the unnecessary (end)

[Raushan]

Thank you, I got my mistake, I should have (ratio_tax(s_ast+1)<1)