fix compute for model1D
fix compute for model1D

SasView/sasview,SasView/sasview,lewisodriscoll/sasview,lewisodriscoll/sasview,SasView/sasview,lewisodriscoll/sasview,lewisodriscoll/sasview,lewisodriscoll/sasview,SasView/sasview,SasView/sasview,SasView/sasview