Artificial intelligence is clearly the menace of the cinematic hour. The old menace posed by the Skynet of the “Terminator” franchise has taken on additional credibility in the era of “big data,” which offers the possibility of algorithmic analysis on a heretofore undreamt-of scale. Alex Garland’s recent thriller “Ex Machina,” however, trades guns for words and explosions for psychological turbulence, raising fundamental questions within a deeply intimate context. “Ex Machina” opens as Caleb Smith (Domhnall