7DIM 7DIM build the invisible 7dim world in the universe The deviation of Trace   Uncategorized   No Responses » Oct 26 2010   The trace function is very commonly used in optimization problem, and I always could not remember its deviation clearly. Just write it down !! $$tr(ABC)=tr(CAB)=tr(BCA)$$ $$trA=trA^T$$ $$tr(A+B)=tr(A)+tr(B)$$