Virasena

Acharya Virasena (750–825CE), also spelt as Veerasena, was a Jain monk and belonged to the lineage of Acharya Kundakunda. He was an Indian mathematician and Jain philosopher and scholar of Digambar sect. He was also known as a famous orator and an accomplished poet. He is renowned for his work on the monumental Jain commentary series on the ''Shatkhandagama'', known as the ''Dhavala'' texts. The late Dr. Hiralal Jain places the completion of this treatise in 816. He played a critical role in the development of Digambara scholasticism and is considered one of the greatest Jain scholars of early medieval India.

Virasena was a noted mathematician. He gave the derivation of the volume of a frustum by a sort of infinite procedure. He worked with the concept of ardhachheda: the number of times a number can be divided by 2. This coincides with the binary logarithm when applied to powers of two, but gives the 2-adic order rather than the logarithm for other integers.

Virasena gave the approximate formula C = 3d + (16d+16)/113 to relate the circumference of a circle, C, to its diameter, d. For large values of d, this gives the approximation π ≈ 355/113 = 3.14159292..., which is more accurate than the approximation π ≈ 3.1416 given by Aryabhata in the Aryabhatiya.