The Relationship Between Yoga and Samkhya Philosophy

There's a close relationship between this text and the Samkhya philosophical tradition which has its own kind of founding document. Is it really two texts that are emanating from the same tradition or is it more like Patanjali's reflecting on Ishvara Krishna? The problem with Samkhya and probably also yoga texts is that much of the literature that may have existed once has been lost in the course of the transmission. So what we have are just pieces of jigs or puzzles and it's our difficult task to reconstruct the past from this.