This section gives an overview on the basic usage of the sparse solvers in STRUMPACK. Many STRUMPACK options can be set from the command line. Running with --help or -h, will give you a list of supported run-time options.

An example Makefile is available in the examples/ directory. This is a simple manual Makefile, with certain variables set during the CMake configure phase, see Installation and Requirements.

STRUMPACK is written in C++, and offers a simple C++ interface. See C Interface if you prefer a C interface. The STRUMPACK sparse solver has three different solver classes, all interaction happens through objects of these classes:

StrumpackSparseSolver<scalar,integer=int> This class represents the sparse solver for a single computational node, optionally using OpenMP parallelism. Use this if you are running the code sequentially, on a (multicore) laptop or desktop or on a single node of a larger cluster. This class is defined in StrumpackSparseSolver.hpp, so include this header if you intend to use it.
StrumpackSparseSolverMPIDist<scalar,integer=int> This solver is fully distributed. The numerical factorization and solve as well as the symbolic factorization are distributed. The input is now a block-row distributed sparse matrix and a correspondingly distributed right-hand side. For matrix reordering, ParMetis or PT-Scotch are used. Include the header file StrumpackSparseSolverMPIDist.hpp and call MPI_Init[_thread].

The three solver classes StrumpackSparseSolver, StrumpackSparseSolverMPI and StrumpackSparseSolverMPIDist depend on two template parameters <scalar,integer>: the type of a scalar and an integer type. The scalar type can be float, double, std::complex<float> or std::complex<double>. It is recommended to first try to simply use the default integer=int type, unless you run into 32 bit integer overflow problems. In that case one can switch to for instance int64_t (a signed integer type).