This repository includes the code used for the paper https://arxiv.org/abs/1603.03301 to find improved lower bounds for van der Waerden numbers. This was a distributed computing project creating used BOINC. That paper provides full details. This README file provides information on compiling and running the code.
Compiling the code requires checking out the full BOINC repository. However, the code unique to this project resides in a single cpp file, uc2.cpp. There are two versions of this code. One, vdw/vdwDaniel/src/uc2.cpp, employs the method of Rabung. This code compiled for Windows can be found in the file vdw.exe. Run this file in a directory that also contains the file "in" with the contents "2,1000" indicating the range of numbers from 2 to 1000+2 to be checked for primes that yield lower bounds for van der Waerden numbers with various numbers of colors and length. It will produce the file "out", with the first line indicating the range "2,1000", and the remainder of the file a table in csv format indicating primes which give a lower bound for a given number of colors and length.
The other, uc2with zipping.cpp, employs Herwig et al's Cyclic Zipper Method as with faster code for checking developed by Rabung and Lotts. This code compiled for Windows can be found in the file "vdw with zipping.exe". Delete the file "out" produced by the previous run, and run the file "vdw with zipping.exe" in a directory with the same "in" file to produce an "out" file renamed here as "out with zipping", where primes that give a lower bound when zipped once are shown multipled by two. For instance, the 7th row has the number 1642 in the first column, indicating that the prime 821 gives an improved lower bound with 2 colors and length 8.
To compile the code, check out the BOINC repository, replace the file uc2.cpp in samples/example_app, and compile example_app using Visual C++ 10 Express, and the compiled file is win_build\Build\Win32\Release\example_app.exe.
The code in work_generator.cpp runs on the server side to create work for the clients, e.g. a file with the name "in" with the entries "1000,250" to check whether any primes in the range from 1000 to 1249 generate any better primes. The code in assimilator.cpp runs on the server side to receive "out" files uploaded by clients, and adding any better primes in these to the servers running tally in "output.txt" for the best primes for a given number of colors and length.