What is the error mean?

What is the error mean?

The following error occurred when converting from CVX to double
Cannot convert from CVX to double
temp(i+1)=(H_U^2+sk(i))/(gama1*pi_f(i));

You probably need to declare temp as an expression holder (array). http://cvxr.com/cvx/doc/basics.html#assignment-and-expression-holders .

Thank you,Mark ! I have solved it.

I have another question.
when I use log_sum_inv() in CVX, why CVX occur the error: Function or variable log_sum_inv() is not defined ? But when I replace log_sum_inv() by log_sum_exp(),there is no error.

Because CVX does not provide log_sum_inv. It would be possible to add such a function to CVX (write your own?) using the formulations in 5.2.7 of https://docs.mosek.com/modeling-cookbook/expo.html , but it has not been.

OK, Thank you for your reply!
I will try to transform log_sum_exp() tomorrow by refering http://ask.cvxr.com/t/using-cvxquad-pade-approximant/1031 .

I am not sure what you are planning, because you link to an already deleted SPAM post. But in the first log_sum_inv formulation approach in the link from my preceding post, log_sum_exp would be used to implement the first constraint in that formulation in CVX.