Install libghc-erf-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libghc-erf-doc
Description:
The error function, erf, and related functions; documentation
A type class for the error function, erf, and related functions. Instances for Float and Double. . This package provides the documentation for a library for the Haskell programming language. See http://www.haskell.org/ for more information on Haskell.
Homepage: http://hackage.haskell.org/package/erf
Version: 2.0.0.0-11build1
Section: universe/doc