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Double Match Triangulator - Version 1.4 - Fri, 20 Jan 2017

DMT is a semi-finalist in the #InnovatorShowdown at #RootsTech 2017. This is a new version of the program with several improvements.

You can get the new version on my DMT page. It is freeware to help you do  autosomal DNA segment analysis.

Now Works with Older CBR files

My own FamilyTreeDNA results came in 11 days ago. When I downloaded my Chromosome Browser Results (CBR) file and ran it through DMT, it didn’t find any triangulations with anybody. That’s because my results were brand new. The other CBR files I had did not know about my results because when they were downloaded, my results weren’t in the system yet.

DMT used to check that Person a’s file had matches with Person b and Person b’s file had the equal matches with Person a. If not, DMT wouldn’t use the a-b matches. So there would be people who Double Matched, but nobody would Triangulate.

To handle this situation, Version 1.4 now only needs the a-b matches in either Person a or Person b’s file. Now you won’t need to update all your older CBR files whenever you get a new tester in your family. Of course, you’ll only Double Match with Person c people who got their results after the older of your Person a and Person b files. Eventually you may want to update your older CBR files with newer ones, especially if there’s a particular Person c missing from the analysis. But updating your files is no longer necessary.

Prevents the Same Person from being used Twice

This was annoying. If you had several CBR files for a person, downloaded on different dates, and you ran By Chromosome to combine everything, then the person would be included as Person b multiple times.

Now DMT checks the names of the Person b people. If the same name shows up, it will only use the last file when ordered by filename alphabetically, which should be the one with the latest date.

This way, you can download new CBR files and leave them with their older ones for comparison, and DMT will only use the newest in its By Chromosome runs.

Excludes non-matches from the By Chromosome Analysis

Originally, I thought it was okay to include all the Chromosome Browser Results files in the By Chromosome analysis. I thought that even if Person b does not match Person a, the Double Matches should still be meaningful.

Yes that is true, but …

This will yield to false interpretation if Person b actually does match Person a on some segments, but they are below the threshold of FamilyTreeDNA to consider them a match. The segments that were a-b matches would then incorrectly show up in DMT as Missing a-b Segments rather than as Triangulations. This is very bad because Double Match Theorem 1 would get you to conclude that this segment is on the other half of the Chromosome pair than it really it. That would make you conclude that this is a paternal match when it is really maternal, and vice versa.

So that had to change. Non-matches are excluded in the By Chromosome Analysis.

Better Handling of Duplicate Segments in CBR files

FamilyTreeDNA unfortunately downloads matches in its CBR files by match name rather than kit number. If two people have the same John Smith, or if one person tested twice under the same name, all those matches will be in the CBR file mixed together looking like one person.  DMT puts a  “##” before the name of people with this problem, so that you will be aware when you use those segment matches.

Duplicate segments will be because a person tested twice. In most cases, all the segments are duplicated (or even triplicated if someone did 3 tests). This case is easy to detect and remove all the extra entries. Then this Person c can be used without worry. DMT now fixes this for you and there is no “##” before these people’s names.

For the overlapping people, if you really need to fix one or two because they are critical in your analysis, you can go to FamilyTreeDNA’s Chromosome Browser and look that name up. You’ll see more than one person. You can download their individual matches and manually doctor up your CBR files, but you’ll have to make up a different name for the other, e.g. John Smith and John Smith2. This is messy because your CBR file for Person b will also have its John Smiths together, and your John Smith2 won’t match anyone in Person b’s file unless you fix that file as well. Ugh!  Better to wait for FamilyTreeDNA to fix this problem, if anyone knows how to let them know about it.

Improvements to the People Page

This is likely the most visible improvement. It is on the People page for individual Double Match runs, and for the By Chromosome run. The two have been made more consistent.


And now all segment matches use consistent notation for the largest Single Matches between Person a and Person c on each Chromosome, 1 to 22 and X (sometimes referred to as 23)

If a-c Triangulate on that Chromosome, then the largest length in cM of any a-c segment that Triangulates is prefixed by the letter "T" and is shown in green so it can be easily picked out, e.g. image

If a-c does not Triangulate on that Chromosome, but does Double Match, then the largest length in cM of any a-c segment that Double Matches is prefixed by the letter "D", e.g. image

X matches will be shown in column ACX with red text and the prefix after the letter "T" or "D" will be "X", e.g.  image or image

Also all Triangulating people are shown first, ordered highest to lowest in their total a-c cM, so the closer relatives will be listed earlier on.


I found that I needed the above changes once I downloaded my own data. I’m sure they’ll be useful to you as well if you use DMT.

It took me 6 days to make these changes. I know I worked hard to get this working over that time. So I was curious and I counted up the number of DMT runs that I had to do to implement, test and debug all this. I was able to total up the number of DMT log files that were created each day. They counts were:

Sunday, Jan 15 - 48
Monday, Jan 16 – 33
Tuesday, Jan 17 - 30
Wednesday, Jan 18 – 80
Thursday, Jan 19 - 73
Friday Jan 20 – 33

Wow! I thought I worked hard on this, but I never expected that it would have taken me 297 runs of Double Match Triangulator to get the changes in this version working.

In total I’ve got log files for 1,668 Double Match Triangulator runs dating back to my first prototype run on June 26, 2016 when I first added the log file.

2 Comments           comments Leave a Comment

1. geniaus (geniaus)
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Joined: Tue, 20 Mar 2012
8 blog comments, 0 forum posts
Posted: Sun, 22 Jan 2017  Permalink

You’re really putting your heart and soul into this - hope it goes well at Rootstech.

2. Louis Kessler (lkessler)
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Joined: Sun, 9 Mar 2003
213 blog comments, 224 forum posts
Posted: Sun, 22 Jan 2017  Permalink

Thanks, Jill.

My motivational goal is really wanting the program to be able to figure out how some of these 7,000 DNA-relatives of mine are actually related to me.

I think ultimately, I can get the program to do it. Slowly getting there.


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