> expression templates bring no benefits to 99% of linear algebra computations If you limit the scope of your statement adequately enough, I would agree. What

> expression templates bring no benefits to 99% of linear algebra computations If you limit the scope of your statement adequately enough, I would agree. What ET did was to remove the overhead that conventional style C++ brought to OOP matrix libraries. Fortran and C would beat C++ libraries hands down. So ET pulled C++ up to level 0: what a naïve (but verbose) implementation in, say C, would have got you. It is only after this the real stuff begins, optimizing for cache reuse, common subexpression elimination. Nowadays there are more advanced ET libraries that do this. > linear algebra computations To elaborate on this a bit more. We usually encounter two broad kinds of operations. One is of the linear algebraic variety, e.g. mat_vec, mat_mat etc. Here ET by itself wont buy you much. Here it is all about cach re-use. The other kind of operations are those chained operations (some times these are called array operations, as opposed to matrix or linear algebraic operations), it is here that ET will show its strength. A high performance library in C++ would typically use ET for these and fall back to BLAS for the former.