This directory has BLAS and LAPACK files needed by the USER-ATC and USER-AWPMD packages, and possibly by other packages in the future. Note that this is an *incomplete* subset of full BLAS/LAPACK. You should only need to build and use the library in this directory if you want to build LAMMPS with the USER-ATC and/or USER-AWPMD packages AND you do not have any other suitable BLAS and LAPACK libraries installed on your system. E.g. ATLAS, GOTO-BLAS, OpenBLAS, ACML, or MKL. You can type "make lib-linalg" from the src directory to see help on how to build this library via make commands, or you can do the same thing by typing "python Install.py" from within this directory, or you can do it manually by following the instructions below. Build the library using one of the provided Makefile.* files or create your own, specific to your compiler and system. For example: make -f Makefile.gfortran When you are done building this library, one file should exist in this directory: liblinalg.a the library LAMMPS will link against You can then include this library and its path in the Makefile.lammps file of any packages that need it. As an example, see the lib/atc/Makefile.lammps.linalg file.