“The Man Who Knew Infinity” tells the true story of an unlikely team that collaborated on groundbreaking mathematical research in the early years of the 20th century. It’s a remarkable example of pure ideas overcoming real-world conflicts like race, faith and class, even if the movie itself unfolds in a fairly unremarkable way.

Dev Patel plays Srinivasa Ramanujan, who grew up in British India with a spotty education but, around the age of 11, emerged as a mathematical prodigy. In his early 20s his hand-scrawled equations earned him a place at Trinity College, Cambridge, in England, under the tutelage of the eminent G.H. Hardy (Jeremy Irons). Despite entrenched racial and class bias, Ramanujan became one of the most celebrated fellows at Trinity since (the movie tells us) Sir Isaac Newton. Both their original notebooks are enshrined on campus.

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The best part of writer-director Matthew Brown’s straightforward drama is the dynamic between the main characters: Hardy’s grouchy atheism versus Ramanujan’s religious devotion, the professor’s intellectual rigor versus the student’s near-magical flashes of inspiration. The two become so close that Hardy counted his collaboration with Ramanujan to be his greatest achievement.

Irons is fine as the tweedy Hardy — all cardigans, pipes and brollies — and the strong support cast includes Toby Jones as number theorist John Littlewood and Jeremy Northam as Bertrand Russell. The film’s British sequences look handsome, while its scenes in India pop with color.

Patel, however, simply isn’t right for the role of Ramanujan. From his breakout film, “Slumdog Millionaire” (2008), through the two “Best Exotic Marigold Hotel” movies, Patel has played the same role: a young Indian brimming with sincerity, enthusiasm and Western aspirations. He plays it again here, but Ramanujan was also a possibly unparalleled genius. Patel never communicates the kind of mental intensity we’d expect from a man who could whip up impossibly complex formulae in his head.

“The Man Who Knew Infinity” shines a welcome light on a lesser-known figure in mathematics, but it isn’t as illuminating as it could have been.