As far as the movies are concerned, great mathematicians are all mentally unstable misfits, weirdos, and social outcasts. What else can we conclude from Good Will Hunting, A Beautiful Mind, and The Imitation Game – not to mention Pi, 21, Fermat's Room, The Oxford Murders, Proof . . . I could go on all day.

Granted, it's more fun to see a genius tear out his hair as he stares, wild-eyed, into the infinite abyss than it is to watch some dude quietly toiling away at his desk.

So it's not a surprise that The Man Who Knew Infinity, a solid, well-written biopic about the great early 20th-century theorist Srinivasa Ramanujan, would take the outcast route, making much hay of the racism and elitist snobbery that the poor, uneducated Indian genius faced throughout his life.

Made on a low budget, writer-director Matthew Brown's feature debut is an easy-to-digest period drama that will feel comfortable and familiar to fans of Downton Abbey and Merchant Ivory. It touches on serious - and ridiculously complex - ideas but always cuts them down to manageable, middle-brow morsels.

Born into a poor Hindi family in Madras, Ramanujan had no formal education but managed to attain a mastery of mathematics rare at even the most prestigious universities. He made substantial contributions to several branches of mathematics, including number theory, before dying in 1920 at age 32 from what is believed to be tuberculosis.

British thesp Dev Patel, who made a stunning debut in 2008's Slumdog Millionaire, is sensational as the soft-spoken thinker. Recently married and penniless, Ramanujan is desperate to find a steady office job as an accountant or clerk, but he's mocked and jeered at by business owners. Undaunted, he stays up at night and slays one monstrous math problem after another.

Patel's performance is so honest and raw, you can feel the passion that drove his character and understand why he believed math to be an achievement as beautiful as painting.

Ramanujan is convinced by a friend to send his ideas to England's top professors, and he eventually earns an invite to Cambridge from G.H. Hardy (Jeremy Irons).

Hardy is warm, paternal - and a little paternalistic. Irons delivers a nuanced performance as the iconoclastic prof, whose motives for helping the young outsider aren't quite as altruistic as he'd like everyone to believe.

The movie does a fine job of evoking the stuffy, stiff, and conflict-ridden academic world that his hero enters, with a strong supporting cast that includes Toby Jones, Jeremy Northam, Kevin McNally, and Anthony Calf.

And yet, The Man Who Knew Infinity is far more sentimental, even maudlin, than it should be. Its portrayal of Ramanujan's relationships with his mother and his wife feels forced. And Brown's direction feels lazy, complacent.

Though it's essential viewing for math geeks, a bold original like Ramanujan deserves a film that's better than just that.