  We work out the effective scaling approach to frictionless quantum quenches
in a one-dimensional Bose gas trapped in a harmonic trap. The effective scaling
approach produces an auxiliary equation for the scaling parameter interpolating
between the noninteracting and the Thomas-Fermi limits. This allows us to
implement a frictionless quench by engineering inversely the smooth trap
frequency, as compared to the two-jump trajectory. Our result is beneficial to
design the shortcut-to-adiabaticity expansion of trapped Bose gases for
arbitrary values of interaction, and can be directly extended to the
three-dimensional case.
