libmathlib2-gfortran binary package in Ubuntu Xenial arm64

 CERNLIB is a suite of data analysis tools and libraries created for
 use in physics experiments, but also with applications to other
 fields such as the biological sciences.
 .
 The mathlib library is a large set of mathematical routines used for purposes
 such as evaluating special functions and integrals, numerically solving
 algebraic and differential equations, performing matrix and vector operations,
 running statistical tests, and generating random numbers in specified
 distributions.
 .
 In order to compile and link programs against this library, you
 must also install the libmathlib2-dev package.

Source package