Sympy and ExprTk¶

SLOTH provides interfaces with the C++ Mathematical Expression Toolkit Library ExprTk and the Python library for symbolic mathematics Sympy to handle physical properties with Coefficient.

Installing Sympy

Sympy is a mandatory prerequisite to build SLOTH. Please ensure that Sympy is well installed.

This page presents the instructions for installing these dependencies.

ExprTk¶

The following installation procedure describes how to install and link the library ExprTk to SLOTH applications.

Getting ExprTk¶

The C++ Mathematical Expression Toolkit Library ExprTk is contained in the C++ file name exprtk.hpp which can be downloaded either from the ExprTk website or with spack by running the following instructions in a terminal:

spack install exprtk

Other approaches exist as, for example, the use of conda.

Linking SLOTH and ExprTk¶

To link SLOTH with ExprTk, the user must run the envSloth.sh script file with the --exprtk option:

bash ../envSloth.sh [OPTIONS] --exprtk=$EXPRTK_PATH

where EXPRTK_PATH is an environment variable setting the path toward the exprtk folder containing the file exprtk.hpp and [OPTIONS] are:

Build type (default: --release):
  --release          Release, with -march=native
  --portable         Release without -march=native (generic x86-64 target on x86)
  --debug | --coverage | --optim | --minsizerel | --relwithdebinfo

Dependencies:
  --mfem=DIR         local MFEM build (instead of spack on Linux / Homebrew on macOS)
  --exprtk=DIR       ExprTk (directory containing exprtk.hpp)
  --voro=DIR         Voro++ installation prefix
  --libtorch=DIR     LibTorch installation prefix
  --external=EXT_LIBDIR,EXT_LIBNAME
                     link Sloth with an external library

Other options:
  --shared           build Sloth as a shared library
  --install=DIR      installation directory (default: ../SlothInstall)
  --np=N             number of parallel compilation jobs (default: 4)
  -h | --help        print this help

Everything after "--" is passed unchanged to CMake, e.g.:
  bash ../envSloth.sh --exprtk=../../exprtk -- -DMATOOLS_VERBOSITY_LEVEL_1=ON

The up-to-date list is printed by bash ../envSloth.sh --help.

With spack, this environment variable can be defined as:

export EXPRTK_PATH=$(spack location -i exprtk)/include/exprtk

Sympy¶

The Python script GenerateCoefficient.py (see the script folder in the SLOTH repository) used to build coefficients from a mathematical expression is built on top of Sympy.

To install Sympy and use the Python script GenerateCoefficient.py, the following instruction can be run in a terminal:

pip install Sympy

Users are free to use other installation procedures as described in the Sympy website.