Matrix Product Toolkit | Installing / QuadPrecision

The toolkit is moving towards supporting quad-precision (via the __float128 GNU quadmath library), and possibly to higher precision via the GMP library.

Moving to quad precision involves several issues

treatment of constants, eg pi, sqrt2, etc need float128 support
BLAS/LAPACK library, it looks like a good candidate is MPACK
EXPOKIT needs porting to __float128. Or maybe use a different library, see eg http://people.sc.fsu.edu/~jburkardt/f_src/matrix_exponential/matrix_exponential.html
ARPACK needs porting to __float128. Probably a big job, but maybe someone has already done it?
Handling adjustable parameters, for example eigensolver tolerances, and default values.