How can the C++ Eigen library perform better than specialized vendor libraries?

Question

I was looking over the performance benchmarks: http://eigen.tuxfamily.org/index.php?title=Benchmark

I could not help but notice that eigen appears to consistently outper

Answer 1

It doesn't seem to consistently outperform other libraries, as can be seen on the graphs further down on that page you linked. So the different libraries are optimized for different use cases, and different libraries are faster for different problems.

This is not surprising, since you usually cannot optimize perfectly for all use cases. Optimizing for one specific operation usually limits the optimization options for other use cases.