Example programs

Here you can find example programs that demonstrate the usage of Ginkgo.

Some examples are built on one another and some are stand-alone and demonstrate a concept of Ginkgo, which can be used in your own code.

You can browse the available example programs

1. as a graph that shows how example programs build upon each other.
2. as a list that provides a short synopsis of each program.
3. or grouped by topic.

By default, all Ginkgo examples are built using CMake.

An example for building the examples and using Ginkgo as an external library without CMake can be found in the script provided for each example, which should be called with the form: ./build.sh PATH_TO_GINKGO_BUILD_DIR

By default, Ginkgo is compiled with at least -DGINKGO_BUILD_REFERENCE=ON. To execute on a GPU, you need to have a GPU on the system and must have compiled Ginkgo with the -DGINKGO_BUILD_CUDA=ON option.

Connections between example programs

The following graph shows the connections between example programs and how they build on each other. Click on any of the boxes to go to one of the programs. If you hover your mouse pointer over a box, a brief description of the program should appear.

Legend:

Example programs

The simple-solver program	A minimal CG solver in Ginkgo, which reads a matrix from a file.
The minimal-cuda-solver program	A minimal solver on the CUDA executor than can be run on NVIDIA GPU's.
The poisson-solver program	Solve an actual physically relevant problem, the poisson problem. The matrix is generated within Ginkgo.
The preconditioned-solver program	Using a Jacobi preconditioner to solve a linear system.
The three-pt-stencil-solver program	Using a three point stencil to solve the poisson equation with array views.
The external-lib-interfacing program	Using Ginkgo's solver with the external library deal.II.
The custom-logger program	Creating a custom logger specifically for comparing the recurrent and the real residual norms.
The custom-matrix-format program	Creating a matrix-free stencil solver by using Ginkgo's advanced methods to build your own custom matrix format.
The inverse-iteration program	Using Ginkgo to compute eigenvalues of a matrix with the inverse iteration method.
The simple-solver-logging program	Using the logging functionality in Ginkgo to get solver and other information to diagnose and debug your code.
The papi-logging program	Using the PAPI logging library in Ginkgo to get advanced information about your code and its behaviour.
The ginkgo-overhead program	Measuring the overhead of the Ginkgo library.
The custom-stopping-criterion program	Creating a custom stopping criterion for the iterative solution process.
The ginkgo-ranges program	Using the ranges concept to factorize a matrix with the LU factorization.

Example programs grouped by topics

Basic techniques

Solving a simple linear system with choice of executors.	The simple-solver program
Using the CUDA executor	The minimal-cuda-solver program
Using preconditioners	The preconditioned-solver program
Solving a physically relevant problem	The poisson-solver program, The three-pt-stencil-solver program, The custom-matrix-format program
Reading in a matrix and right hand side from a file.	The simple-solver program, The minimal-cuda-solver program, The preconditioned-solver program, The inverse-iteration program, The simple-solver-logging program, The papi-logging program, The custom-stopping-criterion program, The custom-logger program

Advanced techniques

Using Ginkgo with external libraries.	The external-lib-interfacing program
Customizing Ginkgo	The custom-logger program, The custom-stopping-criterion program, The custom-matrix-format program
Writing your own matrix format	The custom-matrix-format program
Using Ginkgo to construct more complex linear algebra routines.	The inverse-iteration program
Logging within Ginkgo.	The simple-solver-logging program, The papi-logging program, The custom-logger program
Constructing your own stopping criterion.	The custom-stopping-criterion program
Using ranges in Ginkgo.	The ginkgo-ranges program