I’m physicist looking for a relatively ergonomic linear algebra library to use. Eigen is pretty close to ideal on the “nice to use vs fast” tradeoff, but unfortunately Eigen doesn’t seem to have support for computing Pfaffians.

There is a package “pfafpack” which works with blas and can be called from c/c++ but the Fortran syntax makes the ergonomics much less nice to use, for example I’d much prefer to write

C = A* B; 

than

cblas_dgemm(CblasRowMajor, CblasNoTrans, CblasNoTrans, m, n, k, alpha, A, k, B, n, beta, C, n);

I’ve not been able to find any “nice to use” libraries with this capability after some searching.