The eSTOMP simulator is distributed as source code for a particular operational mode, with the source code required for external packages (e.g., PETSc and GA Toolkit libraries). Assembly of the executable occurs through the make utility (Talbott 1988) which is also distributed with the source code. Except for external packages, the eSTOMP simulator is coded in FORTRAN.
Distributing an open source allows users to read and modify the simulator, which will hopefully result in an open exchange of scientific ideas. A drawback of an open source is that the user is responsible for compiling and linking the source code to generate an executable. Users will also need to compile the external libraries independently of eSTOMP. This inherently assumes that the user has a FORTRAN 90 compiler and is familiar with its use for generating code. The unassembled eSTOMP source is coded in a combination of FORTRAN 77 and FORTRAN 90.