BUG: fix replace for dense
BUG: fix replace for dense

mnicholl/MOSFiT,mnicholl/MOSFiT,guillochon/MOSFiT,guillochon/MOSFiT,mnicholl/MOSFiT,bmockler/MOSFiT,bmockler/MOSFiT,villrv/MOSFiT,guillochon/FriendlyFit,guillochon/MOSFiT,villrv/MOSFiT