In this paper , we report our multiwavelength observations of the large-amplitude longitudinal oscillations of a filament on 2015 May 3 .
Located next to active region 12335 , the sigmoidal filament was observed by the ground-based H \alpha telescopes from the Global Oscillation Network Group ( GONG ) and by the Atmospheric Imaging Assembly ( AIA ) instrument aboard the Solar Dynamics Observatory ( SDO ) .
The filament oscillations were most probably triggered by the magnetic reconnection in the filament channel , which is characterized by the bidirectional flows , brightenings in EUV and SXR , and magnetic cancellation in the photosphere .
The directions of oscillations have angles of 4 ^ { \circ } -36 ^ { \circ } with respect to the filament axis .
The whole filament did not oscillate in phase as a rigid body .
Meanwhile , the periods ( 3100 - 4400 s ) of oscillations have a spatial dependence , implying that the curvature radii ( R ) of the magnetic dips are different at different positions .
The values of R are estimated to be 69.4 - 133.9 Mm , and the minimum transverse magnetic field of the dips is estimated to be 15 G. The amplitudes of S5-S8 grew with time , while the amplitudes of S9-S14 damped with time .
The amplitudes of oscillations range from a few to ten Mm , and the maximal velocity can reach 30 km s ^ { -1 } .
Interestingly , the filament experienced mass drainage southwards at a speed of \sim 27 km s ^ { -1 } .
The oscillations continued after the mass drainage and lasted for more than 11 hr .
After the mass drainage , the phases of oscillations did not change a lot .
The periods of S5-S8 decreased , while the periods of S9-S14 increased .
The amplitudes of S5 - S8 damped with time , while the amplitudes of S9-S14 grew .
Most of the damping ( growing ) ratios are between -9 and 14 .
We propose a schematic cartoon to explain the complex behaviors of oscillations by introducing thread-thread interaction .