simplify md_zwavg
simplify md_zwavg

mjacob75/bart,sidward/bart,sdimoudi/bart,sidward/bart,Takishima/bart,sdimoudi/bart,mrirecon/bart,mjacob75/bart,mjacob75/bart,sdimoudi/bart,Takishima/bart,mjacob75/bart,sdimoudi/bart,mrirecon/bart,mjacob75/bart,sdimoudi/bart,mrirecon/bart,mrirecon/bart,sidward/bart,Takishima/bart,sidward/bart,mrirecon/bart,Takishima/bart,Takishima/bart,sidward/bart