I completed this project as part of the Advanced Practical Programming for Scientists module at the Technische Universität Berlin.

This project uses an improved Steiner graph heuristics proposed by Takahashi and Matsuyama (1980). Parallelisation is also implemented. The Steiner graph problem for graphs of size ~2.0gb can be solved in under 30s.

Specifically, the code computes the best Steiner Tree for a given number of starting terminals (default is 100) and a given graph file.

• Compile: make THREADS=XX, where THREADS=XX specifies the number of threads to be used in the parallel section of the code.
• Compile and run: make THREADS=XX FILE=YY test, where FILE=YY is the graph file to execute right after the target is compiled.
• Run: ./steiner_solver <graph filepath> [# of terminals] [-s]. [# of terminals] is the number of starting terminals to check through to obtain a best objective value. Include the [-s] flag to print the edges of the Steiner subgraph.

• make check runs the cppcheck static analysis check.
• make coverage runs gcov coverage test with lcov results output in folder result/.
• make doc compiles doxygen documentation in folder html/.
• make cleancoverage cleans all files related to coverage test, except the results folder.
• make clean cleans all files created by the Makefile, including the coverage-test related files.

To compile without Makefile:

1. Compile utils.cxx: g++ -std=c++14 -O3 -march=native -pedantic -Wall -c src/utils.cxx -o utils.o -lboost_timer -lboost_program_options -lboost_system -fopenmp
2. Compile heap.cxx: g++ -std=c++14 -O3 -march=native -pedantic -Wall -c src/heap.cxx -o heap.o -lboost_timer -lboost_program_options -lboost_system -fopenmp
3. Compile steiner.cxx: g++ -std=c++14 -O3 -march=native -pedantic -Wall -c src/steiner.cxx -o steiner.o -lboost_timer -lboost_program_options -lboost_system -fopenmp
4. Compile checker.cxx: g++ -std=c++14 -O3 -march=native -pedantic -Wall -c src/checker.cxx -o checker.o -lboost_timer -lboost_program_options -lboost_system -fopenmp
5. Link and output: g++ -std=c++14 -O3 -march=native -pedantic -Wall src/utils.o src/heap.o src/steiner.o src/checker.o src/steiner_solver.cxx -o steiner_solver -lboost_timer -lboost_program_options -lboost_system [-fopenmp]. Include -fopenmp to enable parallelization.