David Vanderschel first learned of Golomb Rulers over a decade ago, and at that time wrote a program to search for OGRs. It was his first "C" program -- called NANT.C -- but it was an order of magnitude better than anything else published at the time.
Mark Garry read the Scientific American article in 1994 (yes, the 1989 article --don't ask!) and used a Fortran program to search up through 16 marks. His posting of a query in the num.analysis newsgroup in mid-1995 led to correspondence and a collection of links to work that others had done.
Combining the works of the two programs into one resulted in a "C" program that searched (exhaustively) faster than any other known programs. Sample solution times on a Pentium-133 pc using GVANT* are:
Number of marks = 13 Solution in 1 minute (48 seconds)
14 Solution in 8 minutes (461 " ")
15 Solution in 80 minutes (4817 " ")
16 Solution in 15 hours (52958 " ")
17 Solution in 2.6 days (225393 " ")
18 Solution in 3.8 days (329488 " ")
19 Solution in 36 days (3 mil " ")
20 Solution in 110 weeks (67 mil " ")
This is a graph of the completion times.
This graph has been adjusted to compensate for different CPU speeds.
We are looking to the internet with "open arms" hoping that there are others out there who might want to get involved either running the current program (written in C) or improving it.
As of 1998, we have met both of these goals! We have a large support base, with people helping to run the programs, others who host required files, others running mail lists, more offering help in the form of golomb distributer servers, and to top it all off, we've had a lot of support on the programming side. For instance, with Rado's help, we revamped some old bitmap code used in Rankin's thesis to run several orders of magnitude faster, so much so, that it runs 2-3 times faster (5 times faster with 64 bit OS's). The new program is offered for download (source code and all) to all interested parties ... look for GARSP** on this web site!
Despite meeting our goals, we find this project to very rewarding, and continue to watch it grow in support as more and more people discover it. FYI, we are a volunteer effort, and follow the policy that nothing being done here is "proprietary" ... rather, it is all open, and all source code remains open to the public to review. So feel free to join our effort if you like, or just peek around at what we've got.
:) The Management
*Garry/Vanderschel ANTenna placment program; **Garry's Adaptation of Rado's Searching Principles