This movie was a true-to-life movie about the tragic life of the very gifted mathematician and mystic Mr. Ramanujan.
I liked the themes of triumph despite English racism to the Indian people.
And I was most glad to see the theme of Faith in God as the source of Mr. Ramanujan's otherwise inexplicable and seemingly magical formulas that came to him entirely completed --- as if glimpsed from the revelations of God. For, every mathematician, deep down, believes they are discovering something already true and pre-existent to their writing it down. Mr. Ramanujan was simply a better visionary than the rest of mathematicians because his formulas came to him already worked out and seemingly out of nowhere. The downside was that he could not really prove that his formulas held. Nor was it evident from the formulas themselves how to prove them, given their quite esoteric nature.
Mr. Ramanujan credited his flashes of inspiration to God (and isn't The Holy Spirit responsible for all inspiration?). But this belief deeply conflicted with the beliefs of the world-famous and very gifted mathematician Mr. Hardy, who was an atheist. Somehow they made their short and brilliant collaboration work. But the movie does not answer --- and I do not know that it can answer, given the historical information that we have --- how Mr. Hardy could explain the flashes of inspiration that came to Mr. Ramanujan while at prayer; or indeed, how Mr. Hardy could explain the existence and nature of mathematics itself.
I find one particular detail about Mr. Ramanujan's formulas that the title of the movie alludes to quite intriguing. For his formulas are technically wrong, as Mr. Littlewood explains in one of his letters. For they often give results that are sometimes slightly higher, and sometimes slightly lower than the true value. But the striking part is that the error in his formulas decreases as the numbers get higher and higher, so that they end up being absolutely correct at infinity --- if infinity were a place the natural numbers could arrive. It is almost as if he had been given glimpses of the "facts at infinity": the view that God must have, since He is not hampered by finitude. Hence the title of the movie: The Man Who Knew Infinity.
Finally, for those of us who know a little bit about the biographies of the mathematicians of the time, the relationship shown in the screen between Mr. Hardy and Mr. Littlewood is quite heart-warming. It brings life to the well-known fact of their life-long collaboration in numerous mathematical problems.