  A simple analytical ansatz, which has been used to describe the intensity
profile of the similariton laser (a laser with self-similar propagation of
ultrashort pulses), is used as a variational wave function to solve the
Gross-Pitaevskii equation for a wide range of interaction parameters. The
variational form interpolates between the noninteracting density profile and
the strongly interacting Thomas-Fermi profile smoothly. The simple form of the
ansatz is modified for both cylindrically symmetric and completely anisotropic
harmonic traps. The resulting ground-state density profile and energy are in
very good agreement with both the analytical solutions in the limiting cases of
interaction and the numerical solutions in the intermediate regime.
