xtensor provides the following error and gamma functions for xexpressions:
Defined in xtensor/xmath.hpp
.. doxygenfunction:: erf(E&&) :project: xtensor
.. doxygenfunction:: erfc(E&&) :project: xtensor
.. doxygenfunction:: tgamma(E&&) :project: xtensor
.. doxygenfunction:: lgamma(E&&) :project: xtensor