Using fminunc() for logistic regression

I've been using fminunc to get parameters for logistic regression for a while now and it was working fine. However, everytime I convert one column of my data into log of that data, it shows the following error: "Objective function is undefined at initial point. Fminunc cannot continue"

Can someone tell me why this is happening?

x is a matrix and I wanted to include log of one of the columns to calculate my parameters theta. It works fine if I don't convert it into log values.

In_cost is a function I wrote to calculate cost and gradient vector.

lambda = 0; 
theta_i = zeros(size(x,2),1);
options = optimoptions(@fminunc,'Algorithm','Quasi-Newton','GradObj', 'on', 'MaxIter', 1000);

[theta, J, exit_flag] = fminunc(@(t)(in_cost(t, x, y, lambda)), theta_i, options);

[the cyclist]

Could you upload your in_cost function and a small dataset that will exhibit the error?

Answer 1

[Matt J]

Can someone tell me why this is happening?

The problem has nothing to do with fminunc. As the error message says, your objective function is not returning a valid value at the initial point. You simply need to call your function with the initial point and observe the output to verify what the message is telling you.

Answer 2

[the cyclist]

Is there a zero in x, such that the log is undefined?

[Sree Bhargavi Moganti]

No zeros and no negative values