When did Ugrādityācārya live, according to the editor, and on what evidence?

Detailed answer

The work cites earlier ācāryas presumed to be before the sixth century, and its closing sentence says Ugrāditya delivered its last section in the assembly of Nṛpatuṅga Vallabha; the editor identifies this king with Amoghavarṣa I, whose accession historians place in Śaka 736 (815 CE) and who was a disciple of Jinasena. He cites Prof. Saletore and Rai Bahadur Narasiṁhācārya, who calls Ugrāditya a contemporary of Amoghavarṣa I and of the Eastern Cālukya king Kali Viṣṇuvardhana V. The earlier introduction by Gaṅgādhar Guṇe Śāstrī infers only that the work is later than Vāgbhaṭa.