Dear all, I am new to CVX. I am trying to solve a primal form and then a corresponding dual form, but the results made me confusing.

From the primal form, the result is as following, where **primal objective value**,**dual objective value** and **Optimal value** are the same value.

**primal objective value** = 9.24733749e+001

**dual objective value** = 9.24733744e+001

gap := trace(XZ) = 4.85e-007

relative gap = 2.61e-009

actual relative gap = 2.59e-009

…

Status: Solved

**Optimal value** (cvx_optval): +92.4734

But from the corresponding dual form, I got:

**primal objective value** = -2.61003379e+002

**dual objective value** = -2.61003382e+002

gap := trace(XZ) = 2.39e-006

relative gap = 4.58e-009

actual relative gap = 4.53e-009

…

Status: Solved

**Optimal value** (cvx_optval): -92.4734

where the **primal objective value**=**dual objective value**, but not equal to the **Optimal value**.(here optimal value of dual form is -92.4734, and we can take it the same as the optimal value of primal form because of some transformation relationship, it is correct).

Can anybody help me interpret what are the **primal objective value**,**dual objective value**, and how they are calculated? Why they don’t equal to **Optimal value** in the dual form result?

Thanks so much.