It’s time for Dev Patel to add fresh paints to his palette. This talented actor — who got his feature start in Danny Boyle’s “Slumdog Millionaire” — has largely specialized in handsome, earnest and well-meaning characters (in both “Best Exotic Marigold Hotel” movies and the canceled HBO series “The Newsroom”). Now comes “The Man Who Knew Infinity,” Matthew Brown’s respectful and, yes, earnest biopic about the early-20th-century mathematician Srinivasa Ramanujan, who found the divine in integers. Ramanujan, who was mentored by the Cambridge professor G. H. Hardy, eventually became the first Indian to hold a fellowship at Trinity College.
We first meet the young, married Ramanujan in a temple in Madras (now Chennai) in India, scrawling mathematical notations like a man possessed. Despite the skepticism of his British boss (a haughty Stephen Fry, barely seen), Ramanujan contacts Hardy (Jeremy Irons) at Trinity with his ideas. And soon he leaves his wife and mother for England. Initially resistant to proofs, he eventually delivers the goods — which yield, among other things, discoveries in the partition of numbers — defying Cambridge bigots and warming the heart of the clinical, atheistic Hardy, as well as those of the scholars Bertrand Russell (Jeremy Northam) and J. E. Littlewood (Toby Jones).
Tidy production values are present (Cambridge locations lend verisimilitude), as is a convenient historical omission (specifically, the real Mr. Ramanujan’s marriage to a 10-year-old girl when he was 21). Mr. Irons handily hits the emotional beats, as does Mr. Patel, as Ramanujan confronts incipient tuberculosis. But perhaps Mr. Patel is now ready to try his hand at a sinner, not a saint.