erebolini / xcfun

Exchange-Correlation functionals with arbitrary order derivatives.

Arbitrary order Exchange-Correlation functional library

Copyright Ulf Ekström [email protected] and contributors 2009-2017. See http://dftlibs.org/xcfun/ for more information.

The main interface is in include/xcfun.h (or fortran/xc_fun_module.f90 for Fortran bindings).

License

The project license is specified in COPYING.md and COPYING.LESSER.md

XCFun is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

In addition to the rights granted to you under the LGPL license (described in COPYING.md and COPYING.LESSER.md) you may distribute the compiled XCFun library statically linked to an application. It is understood that doing so will prevent the end user from relinking the application to a newer version of the XCFun library, but static linking is explicitly allowed by this exception. This exception does not free you from your obligation under the LGPL to provide the full (possibly modified by you) source code of the XCFun library to anyone who receives a copy of the library or an application linked to the library.

XCFun is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

Documentation

• http://xcfun.readthedocs.io

Contribution guide

• All patches are contributed through fork-pull request mechanism.
• We do not require any formal copyright assignment or contributor license agreement. Any contributions intentionally sent upstream are presumed to be offered under terms of the LGPL version 3.0.
• Maintainers do not push directly to the repository.
• Maintainers do not review their own patches.
• Approval of one maintainer is sufficient for trivial patches.
• Trivial patches are typos and trivial bugfixes.
• For any patch that is not trivial, two maintainers need to sign off the patch.
• TODO: We need to better define what "trivial" means.

Configuration

Check that XC_MAX_ORDER is defined to the highest order derivatives you need (and not higher) in src/config.h~. Using a too large value for XC_MAX_ORDER` makes compilation slow and the generated code huge.

Building a debug/development version

Edit the Makefile that matches your compiler (Makefile.gcc or Makefile.intel or ...) to set CXX (C++ compiler) and flags and run

$ make -f Makefile.gcc

(or using the corresponding Makefile) This will create the library file lib/libxcfun.so

Building an optimized version

Edit the Makefile that matches your compiler (Makefile.gcc or Makefile.intel or ...) and add -DNDEBUG to the compiler flags. Add optimization compiler options. Make sure your compiler performs inlining (-O3 with gcc).