A simple lattice QCD library.

The library itself is only composed of header files located in the qlat directory.

The major dependencies are included in the distfiles directory.

There are scripts used to install all the dependencies, which are located in the scripts directory.

The build.sh will install everything into the $prefix directory by running all the scripts in the scripts directory. For example, the following command will install everything into DEST_DIRECTORY.

$ prefix=DEST_DIRECTORY ./build.sh

If $prefix is not set, the default value in setenv.sh is used, which is $HOME/qlat-build/VERSION_NUMBER.

A sample Makefile is provided which can compile and run a simple program using the library. The Makefile assumes that the library and all its dependencies are installed in their default locations.

There are also example programs provided in the examples directory. Once the library is completed installed, one can run the following command to compile all the examples:

$ make -C examples run

const int DIMN = 4;
struct Coordinate : public std::array<int, DIMN> {};

struct GeometryNode {
  bool initialized;
  int num_node;
  int id_node;
  Coordinate size_node;
  Coordinate coor_node;
};

struct Geometry {
  bool initialized;
  GeometryNode geon;
  int eo;  // 0:full; 1:odd; 2:even
  int multiplicity;
  Coordinate node_site;
  Coordinate expansion_left;
  Coordinate expansion_right;
  Coordinate node_site_expanded;
};

template <class M>
struct Field {
  bool initialized;
  Geometry geo;
  std::vector<M> field;
};

template <class M, int multiplicity>
struct FieldM : Field<M> {};

The state of the generator is effectively composed of the history of the generator encoded as a string.

To generate random numbers, one computes the SHA-256 hash of the string. The hash result is viewed as a 8 32-bit unsigned integers.

The 8 32-bit unsigned integers are merged into 4 64-bit unsigned integers. These 4 numbers are treated as the random numbers generated by this random number generator.

Relavent source files: qutils/rng-state.h.

Relavent examples: examples/rng-state-tests, examples/field-rng-tests.