Which South Indian poet and composer has a school of music where Sooryakantam  is called Chāyāvati ?
Suryakantam Suryakantam or Sooryakantam (pronounced sūryakāntam) is a rāgam in Carnatic music (musical scale of South Indian classical music). It is the 17th "melakarta" rāgam (parent scale) in the 72 "melakarta" rāgam system of Carnatic music. It is called Chāyāvati in Muthuswami Dikshitar school of Carnatic music.
Vadya Vadya (IAST: Vādya, वाद्य), also called "Vadyaka" or "Atodya", is one of the three components of "sangita" (musical performance arts), and refers to "instrumental music" in the Indian traditions. The other two components of "sangita" are "gita" (vocal music, song) and "nrtya" (dance, movement). In the general sense, "Vadya" means an instrument and the characteristic music they produce, sound or play out.