The mth library is a library to support mathematical objects (vectors, matrices, tensors) templated over a scalar type and mathematical routines that use these objects. The math routines are intended to support small, dense linear algebra objects.

Static and dynamic vectors are in mthVector.h
Static and dynamic matrices are in mthMatrix.h
Basic linear algebra routines are in mth.h
A QR factorization / solver is in mthQR.h
An automatic differentiation variable is in mthAD.h