Always remind me the Illegal operation: log( {convex} )

this is my code zeta is variable
A1=power(delta,2)+(belta).*p2.*inv_pos(zeta);
R=log(A1)./log(2)
Ii dont know how to deal with this problem

Is zeta the only variable in A1? If so, it should be reformulable per the table in section 5.2.10 of https://docs.mosek.com/modeling-cookbook/expo.html#modeling-with-the-exponential-cone . Whether the convexity (concavity) goes in the “correct” direction" depends on how R` is being used in your problem.

actually zeta is a slack variable ,and the A1 just the part of my goal function .in the matlab i need to deal this problem first

You haven’t provided enough information. The first thing you need to do is prove your optimization problem is convex.

A1 is convex but after add the log ,this problem be the illgal operatrion :log({convex})

i can upload my code ,whether ytou have enough time to deal this problem for me i will appreciate

Have you proven the problem is convex? That is your responsibility. if you need help on that, perhaps post at https://math.stackexchange.com/

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actually in A1 the variable is just the slack variable(zeta)

I ask you for the last time, have you proven this problem is convex? if so, the table i previously referenced should be of help.

yes this function is convex

That’s good to know. So follow my tips and implement it in CVX.

thanks for your advice :grinning: :grinning: