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The primary reason to use libint compiler is to generate custom Libint libraries. Most advanced customization, such as implementation of new integral types, recurrence relations, and computation strategies, will require making changes to the compiler. If you are interested in working on the compiler code please consider consulting with one of Libint authors, if possible, to avoid duplication of effort.
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- Robust C++ compiler with "some" C++0x support;
- Recent boost library;
- Recent GMP library, including C++ support;
- (optional) Recent MPFR library for high-precision (>64bit) testing of the computed integrals;
- Standard GNU toolchain (make, tar, autoconf);
- doxygen and latex to make compiler documentation.
- Git client.
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The only way to get the compiler source is from the Libint source code repository on GitHub. You can use a client, like GitHub app or (our favorite) SourceTree app from Atlassian. Or from the command line: git clone https://github.com/evaleev/libint.git
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- enter the top source directory
- aclocal -I lib/autoconf
- autoconf
- make a separate directory where you will build the compiler (WARNING: BUILD DIRECTORY CANNOT BE LOCATED WITHIN THE SOURCE TREE), and cd that directory
- run configure script with appropriate configure command-line options (see the next section for more info). All available options can be listed as such: [libint_srcdir]/configure --help. Some information can be passed to configure via standard environmental variables:
- CPPFLAGS can be used if the boost library is not in the default compiler search path, e.g. /path/to/libint/source/configure CPPFLAGS='-I/path/to/boost'.
- CXX can be used to specify the C++ compiler.
- CXXFLAGS can be used to specify the C++ compiler flags.
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These are the most useful configure options:
- --enable-eri=N Use this option to enable support for N-th order derivatives of (4-center) electron repulsion integrals. To disable support for ERIs set N to 'no', or use the --disable-eri option. By default, N=0 (i.e. no derivatives are requested).
- --enable-eri3=N Same as --enable-eri, except for 3-center ERIs.
- --enable-eri2=N Same as --enable-eri, except for 2-center ERIs.
- --with-max-am=L Species the maximum angular momentum level for the Gaussian basis functions when computing electron repul- sion integrals. By default, integrals over g-type functions (L=4) are supported.
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--with-cartgauss-ordering=ORDER Specifies the ordering of cartesian Gaussians in shells. The known values are:
- standard (default) -- the standard ordering (xxx, xxy, xxz, xyy, xyz, xzz, yyy, ...); this is ordering of the Common Component Architecture (CCA) standard for molecular integral data exchange described in “Components for Integral Evaluation in Quantum Chemistry”, J. P. Kenny, C. L. Janssen, E. F. Valeev, and T. L. Windus, J. Comp. Chem. 29, 562 (2008);
- intv3 -- the intv3 ordering (yyy, yyz, yzz, zzz, xyy, xyz, xzz, xxy, xxz, xxx) used the by IntV3, the default integral engine of MPQC; use this to make Libint and IntV3 engines in MPQC interoperable;
- gamess -- GAMESS ordering (xxx, yyy, zzz, xxy, xxz, yyx, yyz, zzx, zzy, xyz)
- orca -- ORCA ordering (hydrid between GAMESS and standard);
- bagel -- BAGEL ordering;
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--with-shell-set=SET The library will support computation of shell sets sets subject to these restrictions:
- standard -- standard ordering (default). For (ab|cd): l(a) >= l(b), l(c) >= l(d), l(a)+l(b) <= l(c)+l(d). For (b|cd): l(c) >= l(d).
- orca -- ORCA ordering. For (ab|cd): l(a) <= l(b), l(c) <= l(d), l(a) < l(c) || (l(a) == l(c) && l(b) < l(d)). For (b|cd): l(c) <= l(d).
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this will produce a tarball of libint library that is suitable for independent distribution (it will have its own configure, etc.):
- make export
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Compilation of the generated library is straightforward:
- Unpack the library: tar -xvzf libint-2.x.y-stable.tgz
- cd libint-2.0.0-stable
- ./configure --prefix=.... CXX=... CXXFLAGS=....
- make
- make install
It is very important to use the C++ compiler and compiler options that are appropriate for the given platform. It is impossible to provide specific recommendations for specific platforms. We recommend to use a vendor compiler (e.g., Intel) before trying clang++ and g++. In some situations, however, clang++ and g++ are known to outperform the x86 vendor compiler, so we recommend trying several compilers.
Other important configure flags are described in the next section.
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Besides --prefix and CXX and CXXFLAGS, the following configure options may be necessary/useful:
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--with-real-type=TYPE specifies the data type used by the library. The default is "double" (double-precision floating-point real). The following values are also valid:
- "float" -- single-precision floating-point number;
- "libint2::simd::VectorSSEDouble" -- vector of 2 packed doubles that can be used with SSE2 instructions available on all x86 platforms;
- "libint2::simd::VectorSSEFloat" -- vector of 4 packed floats that can be used with SSE instructions available on all x86 platforms;
- "libint2::simd::VectorAVXDouble" -- vector of 4 packed doubles that can be used with AVX instructions available on recent x86 hardware (Intel Sandy Bridge and AMD Bulldozer);
- "libint2::simd::VectorQPXDouble" -- vector of 4 packed doubles that can be used with QPX instructions available on recent PowerPC hardware (IBM Blue Gene/Q);
- "libint2::simd::VectorFP2Double" -- vector of 2 packed doubles that can be used with FP2 (Double Hummer) instructions available on older PowerPC hardware (IBM Blue Gene/P).
N.B. When SIMD data types are used by Libint, integral sets will be computed in sets of 2 (4). To activate support SIMD it may be necessary provide additional compiler flags -- please refer to your compiler documentation.
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refer to Libint Programmer's Manual for (brief) information on how to use the library in your code.
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- Apple clang++ and MacPorts g++ (4.8) both work with -std=c++11 flag
- MacPorts gmp package works fine