What does the violin do in a Carnatic concert?

In a Carnatic concert the violin is the main melodic accompanist of the voice, and its tone and volume let it blend with the singer. It is tuned to the soloist's tonic, Pa-Sa-pa-sa. It also works as a solo instrument, and Baluswami Dikshitar and Vadivelu are among the musicians credited with bringing it into Carnatic music.