Question: Which South Indian poet and composer has a school of music where Sooryakantam  is called Chāyāvati ?

full_context: Document 1: Melakarta: Mēḷakarta is a collection of fundamental ragas (musical scales) in Carnatic music (South Indian classical music). "Mēḷakarta" ragas are parent ragas (hence known as "janaka" ragas) from which other ragas may be generated. A "melakarta" raga is sometimes referred as "mela", "karta" or "sampurna" as well, though the latter term is inaccurate, as a "sampurna" raga need not be a "melakarta" (take the raga "Bhairavi," for example).
Document 2: Sargam (music): Sargam refers to singing the notes instead of the words of a composition, with use of various ornamentations such as meend, gamak, kan and khatka, as part of a khyal performance. This is generally done in medium-tempo as a bridge between the alap and taan portions. As an example, one could sing PmRSnSRRSRnSPnmPgmnnPmgmRSnS in raga Adana, given that raga's vadi-samvadi and the rules of the raga (see "swara" for explanation of the notes).
Document 3: Deva (composer): Devanesan Chokkalingam, popularly known as Deva, is an Indian film composer and singer. He has composed songs and provided background music for Tamil, Telugu, Malayalam and Kannada films in a career spanning about 20 years. Many know his gaana songs, written mostly using Madras Tamil. He is known as the "Father of Gaana Genre" in the Tamil film industry.
Document 4: Nattakurinji: Nattakurinji is a raga (musical scale) in Carnatic music. It is an "audava janya" raga of 28th Melakarta raga Harikambhoji. This raga is good to sing in evenings. It is used both in Hindustani and Carnatic music.
Document 5: 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.
Document 6: M. Venkataraju: M Venkataraju, one of the finest music directors of Kannada film world, who had a short span of life. He composed very good tunes for few movies due to his sudden demise. He was comparable to G.K. Ventakesh and if he was with us for long then there could have been a very good competition to give us more good songs. One technique he used was Ugabhogas (one of ways in Kannada poetry - Daasa Sahitya has used this more) in the beginning of the songs or just the Ugabhogas were his specialty (SwarnaGowri, Kanakadasa has good examples). He was brother of noted music director M.Rangarao (who famous for Saakshatkaara, Bandhana,etc.).
Document 7: List of Janya ragas: Janya ragas are Carnatic music ragas derived from the fundamental set of 72 ragas called "Melakarta" ragas, by the permutation and combination of the various ascending and descending notes. The process of deriving janya ragas from the parent "melakartas" is complex and leads to an open mathematical possibility of around thirty thousand ragas. Though limited by the necessity of the existence of individual "swaroopas" (unique identities) for the "janya" ragas, a list is never comprehensive or exhaustive. Thus the list below is open to additions or corrections. Moreover, some musicians experiment and use new scales, leading to new "janya" ragas. The 72 "Melakarta" ragas are numbered according to the ancient Indian system for numerical notation — the "Katapayadi system".
Document 8: Muthu Thandavar: Muthu Thandavar (1525 – 1600 CE) (Tamil:முத்துத்தாண்டவர்)was composer of Carnatic music. He was an early architect of the present day Carnatic "kriti" (song) format, which consists of the "pallavi" (refrain), "anupallavi" and "charanam". He lived in the town of Sirkazhi in Tamil Nadu. His contributions to Carnatic music have been largely forgotten and not many of his "kritis" are in vogue today. Muthu Thandavar, along with Arunachala Kavi (1712–1779) and Marimutthu Pillai (1717–1787) are known as the Tamil Trinity of Carnatic music.
Document 9: Madurai Mani Iyer: Madurai Mani Iyer (Tamil: மதுரை மணி ஐயர் ) (October 25, 1912 – June 8, 1968) was a Carnatic music singer, who was famous for his unique style. He was one of the most highly celebrated carnatic vocalists during the first half of the 20th century. He, along with his contemporaries Semmangudi Srinivasa Iyer and G.N. Balasubramaniam, are referred to as the 20th century male trinity of Carnatic music. He was renowned for his adept skills at singing kalpana swarams, neraval, and raga alapana. His music continues to be highly regarding today.
Document 10: Sunadavinodini: Sunadavinodini is a rāgam in Carnatic music (musical scale of South Indian classical music). It is an "audava" rāgam (or "owdava" rāgam, meaning pentatonic scale). It is a "janya" rāgam (derived scale), as it does not have all the seven "swaras" (musical notes). This raga was discovered by Mysore Vasudevachar.
Document 11: Vatapi Ganapatim: Vatapi Ganapatim, also known as Vatapi ganapatim bhaje ham or Vatapi ganapatim bhaje, is a Sanskrit "kriti" song by the South Indian poet-composer Muthuswami Dikshitar (1775–1835), one of the "Trinity of Carnatic music". The panegyrical hymn praises Vatapi Ganapati, Ganesha (Ganapati) worshipped in a shrine in Tiruchenkattankudi in the Indian state of Tamil Nadu. The hymn is composed in Hamsadhvani raga (musical mode), however in tradition of kritis, individual performers add their own variations in the tune. "Vatapi Ganapatim" is described as the best-known piece of Muthuswami Dikshitar as well as one of the most popular compositions of Carnatic music (South Indian classical music school). The hymn is traditionally sung at the beginning of many Carnatic music concerts.
Document 12: List of compositions by Muthuswami Dikshitar: Muthuswami Dikshitar was a South Indian poet and composer and is one of the Musical Trinity of Carnatic music. His compositions, of which around 500 are commonly known, are noted for their contemplative nature and for capturing the essence of the raga forms through the vainika (veena) style that emphasises gamakas. They are typically in a slower speed (chowka kala). He is also known by his signature name of Guruguha. His compositions are widely sung and played in classical concerts of Carnatic music.
Document 13: Hanumatodi: Hanumatodi, more popularly known as Todi, (pronounced hanumatōdi and tōdi) is a rāgam in Carnatic music (musical scale of South Indian classical music). It is the 8th "melakarta" rāgam (parent scale) in the 72 "melakarta" rāgam system. This is sung very often in concerts. It is known to be a difficult rāgam to perform in owing to its complexity in "prayoga" (phrases of notes and intonation). It is called Janatodi in Muthuswami Dikshitar school of Carnatic music.
Document 14: Atana: Atana is a raga (musical scale) in Carnatic music (South Indian classical music). It is a "Janya" raga (derived scale), whose "Melakarta" raga (parent, also known as "janaka") is "Shankarabharanam", 29th in the 72 "Melakarta" raga system.
Document 15: Muthuswami Dikshitar: Muthuswami Dikshitar (March 24, 1775 – October 21, 1835) was a South Indian poet and composer and is one of the Musical Trinity of Carnatic music. His compositions, of which around 500 are commonly known, are noted for their contemplative nature and for capturing the essence of the raga forms through the vainika (veena) style that emphasises gamakas. They are typically in a slower speed (chowka kala). He is also known by his signature name of Guruguha which is also his mudra (can be found in every one of his songs). His compositions are widely sung and played in classical concerts of Carnatic music.
ground_truth: Muthuswami Dikshitar